# Elmer's Tiny in 1/4 scale.



## ttrikalin (Nov 15, 2009)

After building my first ever runner (Elmer's Tiny) and my second ever runner (Elmer's Tiny in 1/2 scale) 

http://www.homemodelenginemachinist.com/index.php?topic=6231.0

I decided to build Elmer's Tiny in 1/4 scale... So I was in serious need of new tools... Feedback in my first post suggested that the task is not trivial... 

BTW, plans are found in this wonderful site... as most of you know  ... go to engine #23...

http://www.john-tom.com/html/ElmersEngines.html

A few weeks back I bothered your graces with my log for the stereomicroscope mount... 

http://www.homemodelenginemachinist.com/index.php?topic=6383.0

So now that I got a set of small drills from HF and a set of mini endmills from EBay I decided to start with the column... 

First, hacksaw to part a small piece of steel... Which I then milled to make square surfaces.







Mill on the floor, lathe on the desk... Mounted on the 4 jaw. This is a Taig 4" chuck that fits my Sherline... It's a bit bulky... I need to get a smaller one... I centered the piece with the indicator, mounted on a home-made base that holds it to the center of the spindle.






Then I turned the stock down to start forming the column... The diameter at this point is 0.189" - it will be turned down further later.






Lathe on the floor, mill on the desk. Indicating a good reference for the Y axis. 






Mounting the piece directly on the mill table. So exciting... 







... and so dummkopf... the screw of the mounting gear (step block) gets in the way... 






... but also the milling collet is practically sitting in the spindle and the headstock does not go so low... so the whole setup was in vain. Anyhow, milling vise. Here I drill the hole that will accommodate the bushing for the crankshaft (and the crankshaft). I started with a #80 drill (why??? - not shown) and then enlarged with a #67 - shown.






Then drill to size with a 1/16". Note that I do not make everything to scale. First I have no tools, second, I think that the shafts will be too feeble if I make them 1/4 scale... Third I could not care less. ;D ;D ;D. I'm sure Elmer Verbung would approve :hDe:






Then I started drilling the hole for the cylinder pivot thingie (shaft). This is a #80 drill, can you see it going all the way through? . I enjoyed drilling with these small drills... it was completely unnecessary though... I made the final hole a #66. Do not ask why. Because. 






Then I milled a small flat where the steam ports would be, and I center-drilled (not shown) the first of the 2 steam ports (not shown). I did not use a jig, as Elmer does. I trig'ed out the location of the holes and did them manually. I aimed to make the holes now that the column has not been turned down to final diameter and is thus more rigid... 

I decided that the holes should be #80. The centers of the 2 steam ports (intake/outtake) are in a 0.023" distance... There is not a lot of room for larger diameters... This thing will need some serious air pressure to run.. if it ever runs... 


AND THEN THE S**T HIT THE FAN. :fan: BIG TIME th_wtf1 !!! The freaking #80 drill broke in the port. I guess I was too drilling-happy... 

Anyway, tried to salvage the part by... taking the broken drill out. *bang*

You know the routine. Mill on the floor, lathe on the desk. 

I put the stereomicroscope on. This is an image of the problem.

You can see the #66 hole for the pivot of the cylinder on the left, and the small flat I milled to facilitate drilling of the steam ports. You see the port with the drill broken in there. The photo does not do justice to the microscope image... I could see the little bugger in there... :redface2:






Since the current diameter is 0.189" and the final diameter is 0.109", there is some meat on the column I can turn down... Do i decided to start turning down to get close to the outer part of the broken bit. 






and then I started eating away the distal wall of the hole, trying to free the broken bit... At this point I could not get the broken part out with a tweezer or anything I have... But running the lathe at highest RMP, it threw the broken bit out. Sweet :-* . (In the photo, the broken drill is still in there.)







After that I turned down the column to its final diameter (for the column "head") of 0.109" and went on to drill the port holes, and the side hole from which steam will come in. 
Again, lathe on the floor, mill on the desk. Here I mill the flats on the column. On one of the them (flats) the cylinder will sit. 






I do not show how I drilled the steam ports (I did). But after being guided by the force and drilling all the holes and the flats without really seeing wtf i was doing, I decided to inspect...

Mill on the floor, lathe on the desk. After mounting and centering on the 4-jaw, a few peeks through the stereomicroscope... 

It is a small bugger.






Here is the hole for the bushing/crankshaft. 






This is the flat from the side of the cylinder. Note that the bigger hole on the left does not sit on the center of the flat... I messed up a tad. Also, the flat is wider on the right and narrower on the left, suggesting that the column was not horizontal when I milled it... OK, I'll fix with fine grit wet dry paper. But LATER. The other two holes are the steam ports. When I center-drilled for the one on top I went a bit down, so there is a chamfer there. Oh well. at least the other one is OK. More or less. For done without really seeing what was done... Enough excuses. Next.






This is the other side, the other flat. Again, the bigger cylinder pivot hole on the left and the outtake steam port on the right. (The other port is a blind hole that meets an ipsilateral steam input side hole.) I know, the flat is not good. It bothers me and I'll fix it. LATER.






This shows the side hole that meets the (blind hole for the) input port. The input port is barely visible on the flat, top right side of the photograph. 






This is how the input port meets the side hole. Bottom right, on the flat you can barely see the outtake port (essentially a through hole). 






And this shows where the intake port stops in the bottom of the well of the side hole...






The column is not complete... I have to fix the flats, clear burrs and turn down a small region in the middle of the column a bit more, as per plans... but this will be done next time. Probably in a couple of weekends... I have a friend visiting and he'll need the room where the home shop is... 

Any advice on how to correct the flats welcome... 

take care

tom


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## 4wheels (Nov 15, 2009)

Hi Tom,
I suppose 1/8 is out of the question? It would be a really small bu88er, eh.
I very much admire your micro engineering and hope one day to build a working steamer on a small brass thimble I bought specially for the task. That was years ago and no doubt it will be years before I attempt an engine. I don't have a clue as to the realitive size of your 1/4 or the 1/2 compared to a "thimble" engine. I'm kinda hoping it's about 1/1.
Anyway keep up the good work and not too more broken drills.
I will be following with much interest.
Cheers,
Brian


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## vlmarshall (Nov 15, 2009)

Lathe on the floor, mill on the table,
I can't see those parts. With a 'scope you are able.

Mill on the floor, lathe in it's spot,
thanks for this thread, showing what's what.

Lathe back again, mill put away,
I'm glad the snapped drill didn't ruin your day.

Now the lathe's gone too, both machines are at rest,
and your workbench becomes the bed for a guest.
 ;D :big:



Anyway, 'gotta love the little Sherlines for portability. Thanks for sharing the many steps you've gone through so far. I'm envious of your stereomicroscope. I use 'em at work, and wish I had one at home, with a ring mount for my camera on the monocular eyepiece.
Also, I see you're using the popular folded waycovers... I've actually made a set, but realized at the last minute that I'd lose a bit of Y travel with them in place...so I'm working on a modification. ;D

Great thread, keep up the wonderful updates.


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## 90LX_Notch (Nov 15, 2009)

Tom,

First off, great start. :bow: Keep up the great work.

I felt the same pain two weeks ago when I snapped a #80 in my column. Since then I haven't had any time to work on mine. (My daughter was born last Friday.)

Where I blew it was trying to do it with the jig. I spent too much time making it only to have it break the bit. I had resolved my self to the notion that I have to remake the column but after reading this I'll give spinning it a try.

To help people understand what you are doing here's a picture of the piston, column, cylinder and bushing. They are all to scale except that cylinder is still attached to the parent material. It is bored and the pivot pin hole is drilled. Also, the rod part of the piston is beefier. 

Secondly, geez I wish I had a microscope. You have the way to go there. The thought of remaking the column has really shelved my desire to finish this.

Bob


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## ttrikalin (Nov 15, 2009)

Bob, 
The daughter is the important piece of news!!! Kudos! th_wav 

I am not skilled so the microscope makes all the difference in the world. I cannot mount it on the mill though. I'm exploring alternatives (e.g., a cheap USB camera with near zoom???) -- Some looney out there has solved the problem... Give spinning a try. I would chamfer the entrance of the hole to remove burrs that hold it in... and get a good magnifier glass or an eyepiece to see if it's out... 



Brian,

I'm sure that Jerry Kiefer (one or two "f"s? :hDe can do the 1/8 with his eyes closed and both hands tied behind his back - but I do not think it's for me, my skills or my toolset. (But I do have a couple of friends who are microsurgeons... I guess that these guys are up to this task...)


Vernon, 

Nice poem - I'll print and hang on the wall. 

Sherlines are great. Pretty accurate for money, very light to carry around, ideal for 30-year old lazybones like me... Also, Anastasia (wife) wants me to do small "metal thingies" -- less swarf oh: . 


tom


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## ttrikalin (Nov 15, 2009)

Vernon  said:
			
		

> Also, I see you're using the popular folded waycovers... I've actually made a set, but realized at the last minute that I'd lose a bit of Y travel with them in place...so I'm working on a modification. ;D



Yes I have this complaint from the popular design too... What mod are you thinking... do you want to post a how to? (and some G code   )


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## vlmarshall (Nov 15, 2009)

ttrikalin  said:
			
		

> ...exploring alternatives (e.g., a cheap USB camera with near zoom???) -- Some looney out there has solved the problem...
> 
> Nice poem - I'll print and hang on the wall.
> 
> Sherlines are great. Pretty accurate for money, very light to carry around, ideal for 30-year old lazybones like me... Also, Anastasia (wife) wants me to do small "metal thingies" -- less swarf oh: .



I've seen a kid's educational toy... called an "EYEclops" I think, that is a USB camera with macro lense, that I've thought about using for miniature work and painting...

The poem... I was half asleep. ;D Seemed like a good idea at the time. Yep, I'm really happy with my Sherline mill, and hope to add a lathe soon.

Lastly, my wife has me making "little metal things" for her, too. ;D


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## mklotz (Nov 15, 2009)

How about a USB microscope?

http://www.thinkgeek.com/gadgets/electronic/9955/

and only $350.


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## Deanofid (Nov 15, 2009)

That's pretty small, Tom! It's a neat undertaking, reducing the size so much.  Making tiny parts like this is where my sins become evident. Every thou counts.

What a nice stroke of luck that the broken bit came out by spinning it. You must be living right.

I have one of the Taig four jaw chucks too, and have owned the Sherline equivalent. The small amount of increased mass of the Taig unit actually works to your advantage. A little extra dampening, and a little more fly wheel effect, which is good for small machines like the ones we use, (Sherline or Taig lathes).

Keep up the tiny work!

Dean


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## vlmarshall (Nov 15, 2009)

mklotz  said:
			
		

> How about a USB microscope?
> 
> http://www.thinkgeek.com/gadgets/electronic/9955/
> 
> and only $350.


 the Eyeclops "Bionic Eye" does 200x too http://www.eyeclops.com/

You just have to pull it out of that goofy eyeball-shaped housing it's in. ;D



			
				Deanofid  said:
			
		

> I have one of the Taig four jaw chucks too, and have owned the Sherline equivalent. The small amount of increased mass of the Taig unit actually works to your advantage. A little extra dampening, and a little more fly wheel effect, which is good for small machines like the ones we use, (Sherline or Taig lathes).


Good point... I'l remember that.


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## ttrikalin (Nov 15, 2009)

Vernon  said:
			
		

> the Eyeclops "Bionic Eye" does 200x too http://www.eyeclops.com/
> 
> You just have to pull it out of that goofy eyeball-shaped housing it's in. ;D



Or, play it kinky or artsy and keep it as is ;D :big:


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## ttrikalin (Nov 18, 2009)

OK, guys and gals... I make the following observations and I try to decide between starting from scratch or adapting... 

Picking up the previous thread... I turned down the lower part of the column. You can see the flat on top, and that the cylinder pivot hole is not centered... I made this observation in the original post and thought that the flats were not perpendicular to the (supposedly centered) hole.






So i decided to use 600 grit wet-dry sand paper to "fix the flats". The distance of the flat surface on the column from the wide surface of the solid block from which I machined the column is 0.139".

It happens that a pair of parallels, 2 layers of 3M double-sided tape and a 600 grit wet-dry paper get to 0.140".






and therefore i have a nice and easy setup to put a great flat on the column. 






The more I applied the paper, the more obvious it becomes that the flat is parallel to the block surface... but the hole is unfortunately not centered. I overdid it here and there is a bit of a flattening on the round part of the column below the column head... (BTW there's no endmill marks -- the surface is great. )






Measuring with a digitizing software (Engauge Digitizer, http://digitizer.sourceforge.net/) the hole is eccentric by approximately 0.012". This is a very suspicious number. It is very near to the displacement of each of the port holes from the centerline. So I mess up when drilling. The whole set of holes is eccentric by 0.012"... 

So the question is... if I make the pivot of the cylinder eccentric by the same amount, do I solve this problem... I think yes, but did not use pen and paper to verify. Not in good mood now .


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## ttrikalin (Nov 18, 2009)

A correction. The holes are eccentric 0.006" to the left... not 0.012". I misstated.






The green line is .109". The blue is 0.007" and the red 0.019".

thanks again, 
tom


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## NickG (Nov 19, 2009)

Tom, 

Wow that is small!

If the crank and the cylinder pivot hole were on the same centreline and they look to be that's good. But the problem looks like it could be your port holes. The centreline doesn't run right between them, 1 looks further from that new centreline than than the other.

I think you may solve the problem by drilling the cylinder port off centre line by the same difference the column ports are away from the crank centreline if that makes sense? Not sure if drilling the pivot off centre would do the same as that - hard to envisage isn't it! Do you have access to 3D CAD? that could tell you. If you give me all the dimensions I could mock up a quick model that should tell you.

Nick


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## ttrikalin (Nov 19, 2009)

Nick, thanks for offering... 

... but I think I got it. It _will_ work by offsetting the cylinder pivot by 0.006" to the correct direction. The whole complex of pivot hole and port holes is eccentric. :- 

Next in line is the _bearing_ and the _crankshaft_... 


Normally I should post these few photos in the booboo section  ... but I think what the heck, my new mess-up is part of the build... :big:
So I turned two bearings out or brass, and I'll have to turn a 3rd one... Well, my bearing number one I kind of lost *club*... It fell on the floor... after 15 minutes of inspection and methodic search I could not find it... 

Till now I realized that when I mess up and my work goes down the drain :toilet: it's better to let it go, and go for a beer... *beer* 

But I had to turn another one... I polished it with 400 grit paper, and I accidentally dropped it on the floor. I put it in a small zip bag I had leftover from some transistors, but it had a hole in the bottom as big as its opening on top... But this time I got it right next to my desk's foot (in the middle, between the 2 strings of swarf): 






Then started turning the crankshaft out of a steel bar I got from home depot. Really bad stuff. Difficult to get a decent finish. I aimed to turn the whole crankshaft from solid. 






To make a long story short, I tested the fit of the bearing to the shaft. I knew it would be tight (hole 0.033", shaft 0.0335") and I press-fit (_*why?*_). I managed to get the bearing stuck on the shaft and to bend the shaft as well.  *club* *club* *club* *club*... the whole thing is scrapped. Anyway... it's a real build with it's ugly turns and the occasional success... next time I'll nail the little mother down...*knuppel2*






*beer*
cheers, 
tom


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## zeeprogrammer (Nov 19, 2009)

I sure hope this doesn't come across wrong...

It reminds me of a few of my evenings...the ones punctuated with 'crap'...'crap'....'crap again'...'fooey'...I sometimes get the feeling that if someone were watching me..it would be a great laugh...like watching Laurel and Hardy.

I sometimes forget myself...but there's no reason why making boo-boos can't be fun either.

I don't have the skill to answer your question about correcting the eccentric...but I can tell you I'm enjoying the posts and the learnings.


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## ttrikalin (Nov 19, 2009)

zeeprogrammer  said:
			
		

> I sure hope this doesn't come across wrong...



I does not come across wrong Zee... I feel the same way... Actually sharing the booboo and the poopoo has a ... cathartic effect (pun intended). 



			
				zeeprogrammer  said:
			
		

> It reminds me of a few of my evenings...the ones punctuated with 'crap'...'crap'....'crap again'...'fooey'...I sometimes get the feeling that if someone were watching me..it would be a great laugh...like watching Laurel and Hardy.



I had this same feeling a few hours ago...  

take care, 
tom


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## ttrikalin (Nov 21, 2009)

Today is another day. The sun would shine in the morning were it not for the clouds, the birds would sing along to my humming were it not for the rain and the cold, and I would get home earlier that I did were it not for a few fires at work.  

What is for sure, is that I had all the motivation in the world to attack the little mother that gave me a hard time yesternight... :-*

So here's tonight's adventure with the little bugger... Second attempt to make the bearing and the crankshaft, and also the opportunity to _correct my blunder_ that was described in previous posts. Briefly, I misplaced the lovely holes for the cylinder pivot and the steam ports by 0.006". 

First, I turned the brass bearing. It downed on me that the best way to align all holes is to _move the crankshaft hole_ by 0.006" in the direction of the error. Therefore, I decided to make an _eccentric_ crankshaft bearing. Eccentric by 0.006", the amount of the error. 


First, I chucked a piece of brass in the 4 jaw, faced, and surfaced it. I center drilled and drilled a 0.033" hole deep enough (>0.125"). Then, I offset the piece horizontally by 0.006", as shown below. Starting position is 0 (do not mind the shadow of the indicator)






and ending position at 0.006":






Then I turned down the external diameter to size. 0.0625" for the rightmost part, 0.081" after the step to the left.






Then I parted off to length (0.125"). A problem was that after parting off a sizeable burr was left on the part. So I ... chucked on the 3 jaw and faced... :shrug: This is after the facing. (My Sherline is huge after all...)






And this shows the eccentric hole that corrects my previous error. 






Now on for the crankshaft. The home depot steel bar I was using yesterday was awful. So I tried a steel nail, which I turned down. I will machine the crankshaft out of the solid. 

This is the shaft, turned to final diameter, with the bearing on it. The bearing fits nicely, with not perceivable play, and slips in and out without sticking. 






Then I parted the crankshaft allowing for enough meat to make the crankshaft disk and the crankpin.






The next step is to put this on the lathe shaft first and turn the crankpin that is eccentric by a few thou. Now I do not have any collets... so I will improvise. I have an idea... I plan to make a one time "collet"... 

1. Sandwich two flat pieces of ally or Delrin together and chuck on the 4 jaw.
2. Drill right where they meet a 0.033" hole, and without unchucking
3. put the shaft in the hole, perhaps with a dab of glue.
4. machine the crankpin eccentric to the shaft by the proper amount
5. separate the parts of the "collet" and clean in acetone. 

I fear that If I do not do a sandwich it will never come out of the "collet". 

What do you think? Am I on for yet another booboo?


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## Russel (Nov 21, 2009)

Do you have a pin vise?

Many pin vises are designed to be mounted in a chuck. Also, and your mileage may vary, rather than facing the bur off of your offset bushing I would have put the part in a pin vise and honed it with an oilstone or maybe 1000 grit wet or dry sand paper and some thin oil.

Just a couple of ideas that you may fine helpfull.

Russ

P.S. I admire you for taking up such a challenge! It's microscopic!


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## hammers-n-nails (Nov 21, 2009)

while were talking about micro-steam i found this a while back http://steamtraction.farmcollector.com/Steam-Engines/Smallest-Steam-Engine-in-the-WORLD.aspx how will the overall size of yours compare?


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## NickG (Nov 21, 2009)

This thing is amazing! Keep up the good work.

Nick


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## ttrikalin (Nov 21, 2009)

hammers-n-nails  said:
			
		

> while were talking about micro-steam i found this a while back http://steamtraction.farmcollector.com/Steam-Engines/Smallest-Steam-Engine-in-the-WORLD.aspx how will the overall size of yours compare?



Hammers-n-nails, 

The simple engine in this build cannot rival the very complex one in the link you posted. The link said the other one has 150 parts made of silver and gold... mine has approximately 10 (I turn some from solid to simplify things and gain strength -- as I hope it'll run)... 

But in terms of sizes, and excluding the base, I have a bigger quarter.  You can see a bit of my other build f Tiny on the right, in 1/2 scale...







Google Jerry Kieffer to see top notch micromachining. He is finishing a fully functional early model Harley Davidson bike in 1/6 scale, with everything scaled down (to the bolt) -- it will have a functional odometer!!! The engine has been finished and it runs!!!


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## zeeprogrammer (Nov 21, 2009)

Good grief that is small.
I'll be you have a fear of sneezing.
Very nice work.


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## ttrikalin (Nov 21, 2009)

Russel  said:
			
		

> Do you have a pin vise?
> Many pin vises are designed to be mounted in a chuck. Also, and your mileage may vary, rather than facing the bur off of your offset bushing I would have put the part in a pin vise and honed it with an oilstone or maybe 1000 grit wet or dry sand paper and some thin oil.



I did not have a pin vise but I bought one today. This is a great little tool and so cheap... I'll make a small adapter so that I can mount it on the lathe (MT1 holder with/out a drawbar). Thanks for the pointer, Russ...


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## ttrikalin (Nov 21, 2009)

Today was mill tramming day. 

Chief Webmentor Jerry G wanted all class members with a mill to learn to tram it correctly... I was delayed in this homework  -- so I had to do it today. 

Because it is the first time I do it correctly (I think) I made a documentary which I'll upload in the Tips and Tricks section. I'm sure most of you know how to do it, but for me it was a whole morning... 

Take care, 

tom


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## Deanofid (Nov 21, 2009)

Glad to see you're still going with the blow-by-blow on your build, Tom. Little setbacks can be discouraging, but you seem to have it under control!

I forgot who it was that had the brass bed Sherline. It's you! 
Nice one.

Dean


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## NickG (Nov 22, 2009)

I'm getting pretty tempted to make a couple of standard tiny's for peoples christmas presents - however, I tried this last year and didn't quite get 1 finished! That was designing my own engine though. The tiny looks pretty simple as there are so few components, I guess keeping the tolerances to let it run is the hard bit!

Tom, how was it doing the 1/2 scale one? Don't think I'd cope with stuff that small! Did you do a build log on that or can we have some more pics?

Thanks,

Nick


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## ttrikalin (Nov 22, 2009)

NickG  said:
			
		

> I'm getting pretty tempted to make a couple of standard tiny's for peoples christmas presents - however, I tried this last year and didn't quite get 1 finished! That was designing my own engine though. The tiny looks pretty simple as there are so few components, I guess keeping the tolerances to let it run is the hard bit!
> 
> Tom, how was it doing the 1/2 scale one? Don't think I'd cope with stuff that small! Did you do a build log on that or can we have some more pics?
> 
> ...




That is a neat idea. 

Unfortunately I do not have any pics from the build of the 1/2 scale -- I made it before joining this family... It was quite a bit of work for me, as it was my second ever engine. But my 30 year old mildly myopic eyes did not need the microscope for that -- OK was pushing it a bit. I could post figures of the 1/2 as it is now if it helps...

Bob [nickname 90LX_Notch] has built a beautiful 1/2 scale -- shown in his avatar next to his 1/1 scale -- he may have pics of the build... 

Bob are you around? Or are you playing with your baby daughter all day? (who can blame you?     )

take care, 

tom


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## 90LX_Notch (Nov 22, 2009)

Nick: My first engine was your design.

Here's the link to the Tiny 1/2 scale build:

http://www.homemodelenginemachinist.com/index.php?topic=4524.0

Tom: Thanks for the compliment. My daughter is keeping us busy, but work is keeping me even more. I just finished a 70+ hour week. I'm starting to get the desire to pick back up on my 1/4 scale build, but as you know you, at this scale it takes a lot of focus and I'm just too tired. I briefly tried spinning mine in the lathe to get the bit out but it didn't work. I'll have to try to debur it and give it another shot. Keep up the good work. You're getting there with yours. Cripes, I started mine in June and you'll be done ahead of me. 

Bob


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## NickG (Nov 22, 2009)

Oh yes, of course Bob, I remember you starting the Tiny after you made my simple engine, didn't realise you'd done a 1/2 scale aswell! Nice 1, they look excellent. I will have to read your build log, the wife is nagging though! I don't think I'd wake up all the following week if I'd done 70 hours! :bow:

Nick


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## ttrikalin (May 28, 2010)

Almost June 2010. Almost good weather outside the half-opened window in our little apartment near the northern end of the orange line. Almost scrapped the almost finished crankshaft from near 6 months ago... 

I'm trying to turn the crankshaft for the 1/4 scale version of Elmer's Tiny from the solid... The modified plans with the scaled down version are in pdf file format here (link in the 2nd line of the narrative):

http://web.me.com/ttrikalin/Machining/Elmers_tiny_1_4_(a).html 

This is the half-finished crankshaft from last November... I intend to turn the crankpin by holding from the shaft (0.032" diameter -- beefed up, not to scale) by off-setting by 0.023"






I decided to mount a piece of delrin in the 4-jaw, and open up a hole that snuggly fits the half-finished crankshaft... like a home-made collet... (_seriously - delrin?_ *bang* ) 






Heres a peek through the stereomicroscope... It is a snug fit... the shafts diameter is a few tenths of a thousand larger...






I will turn the crankpin by offsetting by 0.023. Therefore I turned a reference surface, concentric to the initial hole that holds the crankshaft-to-be. This will help me indicate the offset. 






A small dab of silicone to secure the connection... you may be able to see it spill out where the derlin and the crankshaft meet... 






Next step, offset the crankshaft by 0.023 to turn the crankpin. Start at 0, indicating on the reference surface I turned earlier... 






and finish at 0.023"...






Using derlin was a stupid idea... the connection is not strong enough, and the tool digs in and practically ruins the part... The photo says it all... another difficulty is that with such small parts the machine is relatively huge and there is little sensory feedback while you turn the dials... So i did more damage to the part than needed... but it is salvageable I think...
See the ugly turning job below... from within the stereomicroscope...






Any pointers welcome... 

Oh well... next time... 

take care,

t


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## 90LX_Notch (May 28, 2010)

Go Tom Go!!! Better you then me! I've been wanting to restart on mine, but I can't get that motivated. 

Bob


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## ttrikalin (May 28, 2010)

Bob, I do not really know what to do... 

oh: McGruber time once more... I'm thinking of making a collet holder for a #9 collet that could hold the shaft and then mount it on the 4 jaw to go on with the eccentric turning of the crankpin... 

 :shrug:

too much work to turn a freaking crankpin!


----------



## 90LX_Notch (May 28, 2010)

Tom,

I never finished my crank (3 pc). I have the crank disk: faced, turned to diameter and the holes drilled, but it is still attached to the parent material. 

I thought of doing a one piece crank. My problem is I want to keep it to scale. So at .016 diameter it becomes a little insane.  

Since I don't have a four jaw this how I would attempt it.... 

For a one piece crank I would make an offset bushing out of round stock and hold it in the three jaw. I would use a set screw(s) to hold the crankshaft and then pray to the metal gods for their blessings.

Bob


----------



## GailInNM (May 28, 2010)

Tom,
I built the original Micro HOSC and Steve built an improved version of it. Here is a photo of Steve's.





I don't remember how he built his crankshaft, but I made a split collet of brass. It was 3/16 OD as I recall and I drilled the 1/32 hole for the crankshaft in the mill by offseting the part in the mill. Then I split it almost to he hole with a slitting saw and finished to the hole with a jewelers saw with a 0.006 wide blade. I don't have a photo of it, but it looks like this only on a smaller scale and being so small it did not need the second relief hole. 






Steve is active here most days so you might ask him how he did his. His member ID is: 
stevehuckss396 if you want to PM him.

His plans for the micor HOSC are also in the down loads section at:
http://www.homemodelenginemachinist.com/index.php?action=tpmod;dl=item145

Gail in NM


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## stevehuckss396 (May 28, 2010)

I made all my HOSC cranks the same way. Brass disk with shafts pressed in. My crank for the micro had a .0625 shaft and a .020 arm.

I turned the disk and drilled it. Pressed the shaft in. Then drilled the hole for the arm and pressed that in.


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## ttrikalin (May 28, 2010)

Thanks Steve and Gail and Bob... 

I decided to turn from solid because I was worried that a built-up design (with press-fitting) will not hold if it ever runs... My crank disk had diameter 0.094" and width 0.023"... the shaft had a length of 0.125" 0.196" and diameter 0.032"... 

I write "had" 'cause I foolishly destroyed it in the last few thou of turning the crankpin because the cutter was too low relative to the dimension of the part... I removed the bit to hone it on an oilstone and never centered it precisely... th_wtf1

Too bad... 

Here's making the home brewed "collet" (sandwiched)... the 0.005" brass shims were removed so that the M5 bolt could pinch the shaft... 






and here's the broken-off part, RIP on the "collet", near the screw head ... the still thick end is the crankpin at 48 thou diameter - that broke on it's way to 0.032"... 






I may build it up with press-fits... but I'll give it another try to turn from solid... tomorrow... tonite I have to drawn the sorrow... *beer*


----------



## ttrikalin (May 29, 2010)

*knuppel2* I nailed the little mother... 






Turned from the solid in a single setup... More in a while... going for errands... 
Thanks to all for the pointers... 

take care

t


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## ttrikalin (May 29, 2010)

I started once more to turn from the solid... If this failed Id build it up using press fits... 

First I centered (dead centered) all my tools by taking face cuts on a piece of brass mounted on the 3-jaw... Shown is a microtool holder that I made using Luis Allys (goes by tryally on YouTube) instructions (he is the One). 






I started from a 1/8 steel shaft from a broken #80 carbide drill centered in the 4-jaw. The shaft is not carbide, only the drill is... BTW it machines beautifully... Im happy that I know my machines by now and that I can generally machine within 0.0005... 
When machining such small diameters you have to step it down from left to right in small increments... if you do the whole length at once the tool will deflect the part and youll be turning a taper... Joe Martins book details how to do this... 

Heres the bearing, fits very nicely (as did the previous)... Note that the hole of the bearing is eccentric by 0.006 as stated above... to correct a mistake when making the column. 






Here I have offset the shaft by 0.023 in the 4-jaw... and start turning the crankpin... with very light passes and constant honing of the tool... 






I was angling the microtool to be able to plunge it with the corner... 






I then ground the microtool as a mini left hand tool that is also thin... 






This diameter of the crankpin is 0.032 using the Mitutoyo calipers... cannot mike it in there... (it was OK in the end...)






Parting off...






Success!






Success! Miking it I see that I have the correct dimensions... A photograph blowup and measurement suggests that the eccentricity of the crankpin is 0.022" -- good enough... Here in assembly with the bearing... 






Next is the cylinder...


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## GailInNM (May 29, 2010)

Thm:
Congratulations Tom.
Gail in NM


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## Deanofid (May 29, 2010)

Nice work, Tom! Next time you build something big, it's going to seem so easy.

I've watched some of Tryally's videos in the past. That feller really knows his onions.

Keep up the good work. Don't be a stranger!

Dean


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## 4156df (May 29, 2010)

Tom,
Very nice work. You've proven the old adage: If at first you don't succeed, try, try, again. Also, thanks for the lead on "tryally".
Dennis


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## 90LX_Notch (May 29, 2010)

Tom,

Congratulations! That's awsome man.

Bob


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## Blogwitch (May 29, 2010)

Tom,

I have to applaud your perseverance to get the job finished, and really I should have butted in long ago when I first saw you struggling to get it done.

I only have a large lathe, but small sizes can easily be turned on it. I had a job a few years ago where 0.005" diameter by 3/8" long was required, with a sized head on one end, 50 of them. I had no idea what they were for, I just made them.

The secret is not to fine cut down to size, that usually ends up breaking the pin. What you do is cut down to a much larger diameter, in your case, until you had no interupted cut after doing the offset. Once that stage is realised, you then hit it with one large cut that takes you down to finished size. Doing it that way, you have the support of the large round pin all the way back to the crankdisc. This is a common method used when cutting soft plastics, as if you fine cut down to size it turns out all shapes and sizes because of flex in the material, by doing the 'one hit', you find you can cut them perfectly parallel, time after time.

Bogs


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## ttrikalin (May 30, 2010)

- All, thanks for the encouragement... 

- Indeed Luis Ally is a very good teacher, for me at least... I enjoyed his videos and he seems a cordial fellow... 
(My wife even knows of him "as that dude from Brazil" and she even watched some of his videos with me...)

- Bogs, 
thanks for the advice - you should've chimed in earlier and could've saved some frustration ;D  so take it to the finished diameter with a heavy cut.
I'll follow this when cutting the air tubes... 

t


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## ttrikalin (May 30, 2010)

The cylinder... complete but still on the parent material... Will be parted of in the lathe when the time comes... Will post how it was built... a bit later... 

The cylinder fits in a mental box of 0.078" x 0.094" x 0.114"... bore is 1/16"... Note that it is rounded on the lower part... On the upper surface I put 2 holes, one for the pivot pin (0.032" -visible) and one for the steam ports (0.014" -barely visible, distally by 0.059" from the aforementioned one... ). 







Now I have to go watch sex and the city II with me wife... Getting ready ( *beer* ) 
Any of you seen it? ;D If so did you like it? 

take care, 

t 

ADD-ON MESSAGE:
:-[ back home after the film th_bs - good grief  oh:


----------



## ttrikalin (May 31, 2010)

OK, this piece I CNC-ed. The first run was a disaster, as the X axis of the mill had 7 thou of backlash and this ruined the part. To take the back lash out I had to disassemble the below covers and get to the anti backlash nut and I was postponing it... I had learned to work around the backlash manually. 

After adjusting all axes, I am at <2 thou of backlash (Sherline suggests 3 to 5 thou) and I decided that the cylinder can live with that, especially if I program the CNC to approach from the same direction (which I never did). Funny though how this backlash is extensive for the size of the part. 

Start by using a broken #80 drill (I have plenty of those - broken) as a pointer to position the head approximately to the centre dimple of this faced 0.250 stock. 






The round surface is concentric to the cylinder bore (to mill accuracy) and would suffice to center the cylinder using the 4 jaw on the lathe. 
The flats are perpendicular or parallel to the cylinders flat (the distal face, not shown), and equidistant from the axis of the bore (again to mill accuracy). They will be used to position the cylinder for the pivot pin and steam port holes. 
I admit that I couldve machined the part much better, taking off the 1-2 thou of the backlash with a bit more careful programming... 
next time... 






Out of the vise... 






Drilling the steam port (#80 carbide drill). The piece rests on a parallel and pinched in the vise. I did not square the vise before doing that -- but luckily it was close enough, and to such small distances the error is negligible... I used an edge finder to indicate on the flat surfaces...






A laser pointer shines through the bore -- and through the 0.014" steam port that is exactly at the bottom of the bore.  
Do you see the yellow/red dot just below the point of the drill? This is the shine through the port... Wish I had a better picture... 






Cylinder on the parent material, indicated and with holes drilled...






Coming next the pivot pin that will be press fit on the cylinder... and perhaps a video of the CNC cut... 

take care

t


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## ttrikalin (May 31, 2010)

The pivot pin. The diameter is 0.0005 wider for 0.020 in the left end, from where itll be press-fit in the cylinder...






Press-fitting the pivot pin... on the mill... McGyver moments once more oh:






By 0.020... 






take care, 

t


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## kcmillin (May 31, 2010)

t, sorry to hear about the movie experience, *bang*. 

I am really interested in this tiny little engine, pretty cool stuff.

Kel


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## zeeprogrammer (May 31, 2010)

I've been following along.
Working on stuff this small takes a lot of patience and skill. Good work.

I heard about the movie from daughter...she went with girlfriend and 'boy'friend...dressed up like the cast. They looked great.

That's right. I meant what I said.


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## SAM in LA (May 31, 2010)

Tom,

Your build is very interesting. I can not imagine making anything so small with my lathe. Keep up the good work.

SAM


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## ttrikalin (May 31, 2010)

This is a video of the cut... 

[ame]http://www.youtube.com/watch?v=pcU6Sqx9AZ8[/ame]


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## ttrikalin (Jun 1, 2010)

Thanks to all for dropping a line... Yes, the film was pretty horrendous... :-\ for our (anastasia's and mine) tastes that is... but we're not from the states and there's likely a cultural barrier that prevents us from enjoying it. I'm sure it's full of cultural refs : and pointers that we're oblivious to... Yeah right... Enough with the th_bs ... 

I am not happy with the cylinder, and I will make a new one. 

1. I want to programme the cuts so that the 1 or 2 thou of backlash of the Y or X axis have minimal effect (approach from the same direction and what have you. 
2. I want to bore the cylinder's inside to clean up the shavings of brass that the press-fitting of the pivot pin pushes in the cylinder, and to have a great surface... So I'll change the bore to 0.047" instead of 0.063" (current)... this will make the walls a bit beefier... 

I am getting close to finishing the little bugger and I wish it will run... 

Oh well, we are still a bit far away from that...


----------



## kcmillin (Jun 1, 2010)

Having never seen the movie myself, I can say it has nothing to offer :big:

I'm pulling for ya. These little steamers seem to be quite the challenge. But you are off to a great start. and CNC, shoot, you got it.

Kel


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## ttrikalin (Jul 3, 2010)

Found some time to get to the little engine... How easily did this thread slip to the 5th page... people are very active... 
I had to make the cylinder 6 times... :-[ This is the 6th...
Following advice from Jerry G I used blue loctite to secure the pivot pin and then drilled the cylinder's hole (bore). 

Then I cut off the cylinder with the slitting saw, mounted on the home made arbor.






Cylinder with pivot pin on the pink ruler...






A better view through the microscope...






The orifice of the hole (0.044)...






Observe this setup... the laser pointer is mounted on the green vise and shines the assembly of the column and the cylinder/pivot pin... 






In fact the beam is reflected on the base of the column and into the hole of the cylinder. 
In the next photograph you can see the red light through the outlet port of the column (a through hole), which aligns perfectly with the port of the cylinder... :-*






The red light you see through the outlet port is the shine of the distal wall of the cylinder interior...






If you change the angle of the cylinder, no light...






Next, the piston... and then the flywheel... and then we're almost ready for a test... then tears :'( then *beer* ... 

Take care, 

tom


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## SAM in LA (Jul 3, 2010)

Tom,

You are working in a completely different world than most of us.

I am truly amazed with the precision and the smallness of the parts you are making.

SAM


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## ttrikalin (Jul 3, 2010)

Hardly, Sam, hardly...
Thanks for watching... If this runs I'll start on an IC engine perhaps the Lobo Pup that Gail in NM designed... 

t


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## ksouers (Jul 3, 2010)

Tom,
Amazing stuff.
Way too teeny tiny for me.

I've suspected for some time now that you were a doctor.
Now I'm thinking of amending that to arthroscopic surgeon.


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## Blogwitch (Jul 4, 2010)

Tom,

Now you are getting to the air in stage, maybe a little pointer on the way I achieved mine.
If you have access to syringes, the needles are a perfect job for the inlet stub.

For the very fine flexi tube, I used the tiny sized silicon tube used by European fishermen as shock leaders when using what is called a 'pole'. In the US try here.

http://www.smallparts.com/Medical-G...383597011&pf_rd_p=1261382302&pf_rd_s=center-3

The stuff we can get goes down to minuscule sizes, and is fed onto the needle inlet and wrapped with a couple of turns of very soft wire to keep it in position. Another more robust connection was made well away from the engine to drop the tubing size down to the one going to the engine, this kept the model itself looking more presentable.
Available here, second one down.

http://www.tidaltackle.co.uk/prods.asp?cID=2&sscID=52


You can see what I mean on this vid, although this is a lot larger than the one you are making, the air inlet was one of the major problems.

[ame]http://www.youtube.com/watch?v=76_TtDfYPCo[/ame]


Bogs


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## ttrikalin (Jul 4, 2010)

kevin,
I am an MD but not a surgeon - in fact I do more theory and mathy stuff and do not see patients -- researching under the aegis of a Boston establishment... So no professional skills at work - evident from the number of parts I've scrapped till I get a relatively good one... 

bogs, 
I did have some thoughts on supplying air... I like your solution very much and I'm sure it'll work... I was going to apply lessons learnt from McGyver moments of times past. I shall post an example in my next reply... Is this tiny your own design? Beautiful and so smooth a runner... 

tom


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## ttrikalin (Jul 4, 2010)

This is the schematic of the planned air supply... I have to change the CAD settings (re: number of points drawn) -- see that circles are rendered as polygons... But that's fine... 







This is the 1/2 scale of the tiny where I came up with the idea... Air is pumped into the hole in the base, and then goes up in the vertical tube and then through a bridge to the inlet... 






I'll try to turn the tiny metal tubes out of brass -- If I cannot I'll resort to syringes... 

Now I'll admit that I did shy away from my original plan, which was to drill a hole from the base upwards, to meet the blind hole of the inlet port... In other words, 'replace' the vertical column with a hole that is _in the column body_ a few thousands below the surface... It is theoretically possible, I can draw it, can't I? oh: The neat thing would be that that version would leave you scratching your head to see where the air comes from...
Oh well, we know what to do in version 2... 

thanks for your pointers gents,

take care, 

tom


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## Blogwitch (Jul 4, 2010)

Tom,

Not my own completely. I took the port and crank positions from Tubal Cain's 'Jenny Wren' and made mine around those.

This is the 'Jenny Wren', a combined boiler and engine (not mine, just one I found on Youtube). The engine part without the flywheel is about the same size as a filter tip on a cigarette.

[ame]http://www.youtube.com/watch?v=6wIpXQlH6Ek[/ame]

The whole lot was made in less than a day in the shop, winging it as I went along. The main column and engine backplate is all one piece and the circular base is in fact a 1 Euro coin, to give it a bit of value. A rather large bore of 0.125".
Apart from the air feed problem, getting a cylinder spring small enough was another. I think mine came from a stripped down disposable lighter. And yes, it runs like a Swiss watch on a couple of PSI, any more and the cylinder gets blown off the port face.

Your idea for air feeding externally is very feasible, unfortunately, it might just be me, it makes the engine look a lot larger, and really defeats the object of making it so small in the first place, other than for your satisfaction knowing you can do it. 
It is an age old problem with tiny engines, getting the feed to them in some sort of scale as the engine itself.

Bogs


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## ttrikalin (Jul 4, 2010)

Bogs, 

Thanks for the reply. I do have a question that I have not solved and your post reminded me of that. 
I cannot see me making a spring this small. (We are talking about the spring that makes the cylinder stay in contact with the column... )

I saw somewhere (Dean's website? http://www.deansphotographica.com/machining/taig/soigotataig.html ) a tutorial for making springs on the lathe, but here we're talking quite small... Not sure I'm up to the task... 

I managed one for the 1/2 scale, but for the 1/4 scale I was thinking of experimenting with small pieces of rubber band of various thicknesses... 

Any pointers welcome... 

take care 

tom 

ADDITION

PS. I cannot find the _make-a-spring_ tutorial in Dean's website... So it may be somewhere else I saw it...
Your Graces will forgive me for the false pointer... but Dean's website is worth many visits...


----------



## ksouers (Jul 4, 2010)

Tom,

Dean had two threads on springs. He might not have put them on his web site, but he did the tutorial here.

Here is the one for thin springs:
http://www.homemodelenginemachinist.com/index.php?topic=8253.0

And for thicker ones:
http://www.homemodelenginemachinist.com/index.php?topic=8258.0


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## Blogwitch (Jul 4, 2010)

As I said Tom, it might pay you to buy a couple of disposable lighters and strip them down. Get the ones with filler valves in the base, you should be able to get a couple for a buck. I always pick up discarded ones in the street, when the dog is taking me for a walk. There are usually a least a couple of tiny springs in them.
Springs are one of the things I do keep when stripping things down for recycling.

Or if you can find a small enough tension spring, just overstretching it will turn it into a very useable compression spring at these sorts of sizes. 

You should get away with a small piece of wide elastic band with a hole thru it, then a small washer followed by two nuts. As you are only using air there are no problems with heat, but the nuts would have to be very finely tuned to ensure you don't have too much friction.


John


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## ttrikalin (Jul 4, 2010)

Yes Kevin this is what I had in mind.
John, I'll follow what you say. 

t


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## Deanofid (Jul 4, 2010)

Hi Tom;
I don't know what happened to the link to the spring making pages on my home page. Just disappeared!
I'll work on it. In the mean time, the ones that Kevin has are the same thing.
Also, the link to the pages on my website is still active:
http://www.deansphotographica.com/machining/projects/springs/springs.html

Dean


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## Deanofid (Jul 4, 2010)

Oh! I found the problem, Tom. You're using the link that originates from my camera repair home page,
or the one from Nick Carter's web page. That one is supposed to point to my main macining page, but for some reason it's going to a back-up page, which is slightly out of date.
Sorry!

This is the correct link to my main machining page, which contains the spring making page, too:
http://www.deansphotographica.com/machining/projects/projects.html
Glad you brought it up. I need to update the back-up page!

Dean


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## ttrikalin (Jul 4, 2010)

Yes you are right. I got there through the photogrphy site... 

Awesome stuff I may say ... .


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## shred (Jul 5, 2010)

I ended up using a couple tiny o-rings as the spring on my Jenny Wren. They aren't the prettiest, but work ok. You're working another big step down the size range, so I'm not sure you can even get O-rings that tiny. Another option might be to take a slice of some springy plastic tubing and drill it cross-wise, making a double leaf-spring. Or maybe even rip apart an old relay and make a spring out of the bronze contact leaf-- that might look better on a metal model.


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## ttrikalin (Jul 5, 2010)

Nice ideas, thank you shred.


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## ttrikalin (Jul 10, 2010)

T'is the day for the piston... the diameter is 0.044". The length is 0.168". The hole for the crankpin is 0.031" and pretty well located I dare say. : Beefier than the exact 1/4 dimensions... But who cares... Low magnification... 






Higher magnification... 






It fits very well in the cylinder hole, with nice clearance... 

take care, 

tom in MA


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## ttrikalin (Jul 10, 2010)

Here's where we are at this point... 
- one piece crankshaft out of steel (from a broken bit) is on the guy's chin 
- brass piston on the back of the guy's head
- brass bearing on the neck 
- assembly of steel column and brass cylinder/steel pivot pin just shy of the ponytail






We still miss the flywheel and the spring-- or whatever contraption I'll use to keep the cylinder pressed on the column, as per advice received above... 

take care, 

tom in MA


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## Blogwitch (Jul 11, 2010)

Tom,

I have been thinking of your spring problem at this size, and have maybe come up with a simpler solution, requiring less parts.

If you look at the attached C-o-C, you will see you just have a stub into the pivot hole, and a tiny shim spring to hold the cylinder in place. The screw could be mounted on the back face if needed. You could fine tune by just bending the shim spring until the correct pressure is obtained.


Bogs


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## ttrikalin (Jul 11, 2010)

John 
this is a very smart and elegant solution. Thank you, I shall definitely explore this. 

tae care, 

tom


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## kcmillin (Jul 11, 2010)

Extraordinary Work Tom.

Them part are absolutely minuscule.

Well Done Thm:

Kel


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## SAM in LA (Jul 11, 2010)

Tom,

I am amazed with how you can make such tiny parts.

I would be interested in seeing the setup you use while machining.

Keep up the good work.

SAM


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## Deanofid (Jul 11, 2010)

This is every bit as much a 'wow' thread as any of the larger builds here. 
Excellent sub-miniature machine work, Tom!

Dean


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## NickG (Jul 12, 2010)

Unbelievably small, nice work! :bow: Good idea with the spring Bogs.


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## ttrikalin (Jul 13, 2010)

thanks all for input, ideas and encouragement. 
Last sunday I made a booboo while drilling the column... :wall:
I will have to repeat the part or repair... will post photos... and ask for advice...

take care, 

tom


----------



## ttrikalin (Nov 28, 2010)

More than a few months later, this morning I was able to finish all the parts of Elmer's tiny in 1/4 scale. On with assembling the parts...

I had to machnine the airducts. Because the engine is so small, I have to supply the air through the base. 

These are 2 parts that will form the ascending airduct (My drill is a tad short, and I had to build the duct up from 2 parts). The part that is laying down is 0.285" long, with a stem of 0.044" diameter. The upright part is the lower portion of the ascending airduct, has an external diameter of 0.0531" and it's upper part has a hole at 0.0445" to receive the other 







The two parts loctited together






And with the horizontal bridge that will connect to the main column of the engine. 






This is how it fits the main column of the engine. If you were following the thread you may remember that my mill has had an extensive 6-7 thousands of backlash which I mistakenly did not account for when drilling the ports and holes, which ended upp 6 thousands off center. To correct the geometry I made an eccentric bushing for the crankshaft - eccentric by 6 thousands. :-*






Crankshaft in place, cylinder and piston assortment on the left.






They fit...






Note the long pivot pin -- it is meant to have a tiny spring to hold the cylinder in place... Instead of a spring I'll use another solution (thanks Bogs)...






Another view...






Another view...






With the flywheel...






Another angle... 






Together with the 1/2 size of Elmer's tiny I made last year... 






And together with the full size of the tiny...






Next week, perhaps, I'll implement Bogs' solution to replace the string... and test if it runs... 

till then take care, 

tom in MA


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## NickG (Nov 29, 2010)

Wow! I'll have to look at the sizes again to get an idea of scale, it's deceptive! :bow:


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## arnoldb (Nov 29, 2010)

Great job Tom - that really is a small little engine. I can't wait to see how you retain the cylinder - and to see it run!

Regards, Arnold


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## ttrikalin (Nov 29, 2010)

Yes, it's been a trip... even if it does not run in the end, I couldn't care less. I learned so much, made new tools to make the parts, tuned my lathe and mill to watchmaker precision... I enjoy it. Next weekend I'll try to run and trouble shoot. 

tom in MA


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## mklotz (Nov 30, 2010)

Nicely done, Tom, but if you're going to show us such fine miniature work, flaunt it! Put some common object in your pictures that establishes the scale of your work.

I've built Tiny so I know just how difficult it would be to build it in quarter scale but others unfamiliar with the engine won't grasp just how small it is.


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## kjk (Nov 30, 2010)

I'm trying to get my head around how small this is and having now looked at the plans for the original "Tiny", I am absolutely amazed.

a 5/32 diameter flywheel on a 1/64 inch axle. Wow! this thing is small.


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## NickG (Nov 30, 2010)

Wow, those sizes really tell the story - if possible it'd be good to include something in the pic to give an idea of scale (picture is worth 1000 words!) e.g. an m&m or coin to name two items that have been used!

Well done again tom, as you say, even if it doesn't run it's still a great achievement.

Nick


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## ttrikalin (Nov 30, 2010)

Ok then, perspective... 






and a close up using a reference unit...






Regarding size, I would not be able to machine the parts without a stereomicroscope. It is a bit rough in manual rotation, the bore is most likely not smooth... damaged during fitting? :-[ I'll see next weekend... :-X


take care, 
tom in MA


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## kustomkb (Nov 30, 2010)

Amazing work Tom, very impressive. I hope you get it running.

Just a thought, when you shoot a video, try to leave no reference of scale in the frame and after it has run for a bit move in with your finger. They'll say "Bawaaa!?"


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## BlakeMcKee (Nov 30, 2010)

Wow thats a tiny engine, nice job!


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## NickG (Dec 1, 2010)

Wow - other than that I'm speechless!


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## Maryak (Dec 1, 2010)

Tom,

I can barely see it let alone make it. That's amazing. :bow: :bow:

Best Regards
Bob


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## Groomengineering (Dec 1, 2010)

I make swarf bigger than that...  (but not as nice). Amazing work Tom!

Soooooo..... 1/8 scale next? ;D :hDe:

Cheers

Jeff


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## ttrikalin (Dec 3, 2010)

We _do not_ have a runner . Near the top dead center the piston stops as if it hits a ridge in the bore- you can turn it with force and it overcomes it... but I think that we need an overhaul :big: . 

So tomorrow, I'll probably make a new cylinder out of steel. There is not enough meat on this one to rectify the bore (and it'd take too long to set up... longer than cutting a new one... another cylinder in the scrapbox.... all this material I throw away... Rof}). 

 

till tomorrow then

tom


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## NickG (Dec 4, 2010)

Nearly there Tom - what a waste of material though :big:


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## ttrikalin (Dec 4, 2010)

OK, started machining the cylinder out of steel on the 4-jaw... manually this time, not CNCed. I want the pivot pin and the cylinder machined out of the solid. This will allow me to pursue a bigger bore, and increase the likelihood it'll run. If the cylinder and the pivot pin are not one piece, you need a thicker cylinder wall to press-fit or loctite the pin in it. If the assembly is one piece, you can afford a bigger bore. 

Starting from a 0.250" piece of steel I machined the pivot pin, which is 0.0315" in diameter. It is eccentric to facilitate later setup. 






Digging in the corner where the pin meets the face with a sharp cutoff tool. I undercut a bit, to ensure that the faced surface will be flush on the column when the cylinder is done. 






I offset by 0.059" and drilled the port hole, using the tailstock adapter to center the drill. 






And here is the drilled port hole 0.016", at a depth of 0.047".






tomorrow morning mill time. 

take care, 

tom in MA


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## NickG (Dec 5, 2010)

That probably is the way to do it for this one Tom - what you've said makes sense, not easy though :bow:


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## ttrikalin (Dec 8, 2010)

An update... Overhaul completed last weekend... A new one piece steel cylinder and pivot pin replaces the previous brass cylinder and steel pivot pin. I did not round the corners of the new cylinder. Also the bore is a bit bigger (0.055"). You'll see it in the next photos. Attempt to implement John's solution... Here is a piece of brass shim, flattened out... 






and this is the shim holding the cylinder on the column. It will sit on the centerline of the pivot pin. Here it is approximately positioned. 






Another view... 






Another view... 






It did not run, but I think I'll make it in the end. 

1. The piston moves smoothly and with nice clearance. It may be a bit tight for this size, but the movement is smooth all around.
2. The geometry of the ports is correct. When I position the piston over the intake port and start the air, it moves to the bottom dead center, but the flywheel is small, stores too little energy and cannot self-start. 
3. I will have to use an electric starter motor to turn the flywheel until the engine starts under air.. It is very small, I can not give it a flip with a finger nor a string. 

take care, 

tom in MA


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## arnoldb (Dec 9, 2010)

Thanks for the update Tom  - I get the cylinder retention method now :bow:

Regards, Arnold


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