# A raw beginner attempts an Elmer's 25



## clivel (Apr 23, 2012)

It didn't take long for reality to set in before I put aside my plans to build a 5" gauge loco in favour of something more suited to my limited equipment and even more limited experience.
A rummage through the storeroom-cum-garage-cum-workshop soon unearthed a box containing two sets of rusty castings; one set each for a Stuart 10V & 10H that I had been given a few years back. Heading over to the lathe I whiled away a pleasant few hours experimenting with holding the castings in the lathe chuck or on the milling table in various configurations, but I just couldn't work up the courage to actually attack those expensive and now hard to obtain castings with a cutting tool. So the castings were once again packed away and a decision was made to attempt a relatively simple engine that I could possibly complete successfully which could also be constructed from easily replaceable stock material. A perusal of the web turned up a wealth of possibilities of which I eventually decided on a little oscillating engine - Elmer's #25.

My "workshop" consists of: a workbench in the corner of the garage, a Unimat PC Basic lathe/mill, and the miscellaneous hand tools, measuring instruments and other odds and ends that I have managed to accumulate over the years.







The wooden rectangle in the middle of the bench on which can be seen the embryonic bits of my budding engine, is a cover for a 9 x12" granite surface plate. There is nothing too remarkable about the cover other than the brass screws I first tried assembling it with. These were bought at one of the big-box DIY stores, no country of origin on the label, just marked imported, three guesses as to where they were made?




And that was after I had pre-drilled the holes in the soft wood used for the sides!

-------------------

Actual engine construction started with a piece of 1/4" thick aluminium that was soon destined to become both the frame and the base. I initially planned on using the mill to machine the frame to shape, but never having used a mill before I instead opted for a hacksaw and some files. On the whole I am happy with how it turned out, but the inner curved corner does have a slight kink where it joins the straight.

The frame was then followed by the rectangular base. This time I threw caution to the wind, mounted the milling vice on the mill table and milled it to size ... eventually ... on the third try. What was not immediately apparent to this novice, is that when the table is traversed, that unless both vice and table are scrupulously aligned to the lathe axis, nothing comes out parallel.

Next puzzle to solve was how to align the frame and base for drilling the fixing holes. After marking out and drilling the two holes in the base to tapping size, I eventually hit on clamping the frame to the base, aligning it correctly, turning over and then clamping the clamp in the drilling vice.





For some reason figuring this out (and I am sure there is probably a better way), something that is probably trivially simple to an experienced machinist, gave me an enormous amount of satisfaction.

After drilling the crankshaft bearing and pivot pin holes in the frame, the port drilling jig was made up out of a strip of steel with three carefully placed holes. The next item, was my first real turning job - the 'locating pin'. This is used in combination with the port drilling jig to place the port holes in the frame as can be seen from the next picture.
Prior to this I had only really experimented with the lathe i.e reducing scraps of metal to swarf. Now I was faced with turning something a close fit. On my first attempt I completely overshot the mark, but my second attempt was much more successful. This probably had something to do with the realisation that those markings on the hand-wheels are actually useful and accurate!






That's it for today, so far it has been fun  But what came as the biggest surprise to me is just how little time is spent actually machining in comparison to marking out and setting up.

The other thing that surprised me is just how much arithmetic is involved in machining a part to size. The plans are in fractions of an inch, the digital vernier in decimals both inch and metric (which also makes it a handy tool for converting between the two) and the lathe dials are metric. I don't want to get into a metric versus imperial debate, but as someone who is comfortable with both systems, I found metric with its consistent use of decimals so much simpler to use as a beginner when compared to the dual format fractions/decimals used with inches.

Clive


----------



## 90LX_Notch (Apr 23, 2012)

Clive-

Welcome to the madness! You're off to a great start.

-Bob


----------



## AlanHaisley (Apr 23, 2012)

Clive,
If you want to use those brass screws (regardless of planet of origin), try two thing. First, after drilling the pilot hole, insert a steel screw of the same size as the brass one. Second, before inserting the brass screw, apply a little bee's wax (never soap) to the threads.
In fact, if the wood is a hard wood, you will probably want to wax the steel screw to put it in.

(If you have trouble finding bee's wax, you might have luck with a :toilet: bowl wax seal, although they are compounded a bit softer than the straight wax.)

Alan


----------



## mklotz (Apr 23, 2012)

Clive,

Congratulations on opting to work up to castings and locomotives gradually. You'll relish the wisdom of that decision in the future.

If you're buying brass items at the big box stores, be sure to carry a magnet with you. Don't buy any of the magnetic brass. You'll be surprised at how many items are nothing but brass plated steel.

As you learned, aligning the vise to the mill traverse is critical. Most of us use a tool called a DTI (Dial Test Indicator) to do this job and many other alignment tasks common in the shop. 

I started out with a Unimat. I had no DTI nor was there headroom under the spindle to use one. I made a T-shaped strip of aluminum and bolted it to the mill table doing an eyeball alignment. I then took a cut across the end of the T crossbar and, _voila_, I had a reference edge parallel to the table motion. Using this I could align accessories by butting them against the rail. Later I added another T-rail so I could align in both directions of the table movement.

Your observation about the ratio of setup time to machining time is right on the mark. While the novice might take slightly longer setting up, even experienced practitioners spend far more time on preparation than cutting metal.

Despite living in the last holdout of the Inferial system, I have to agree that the metric system is far superior, and not just for machining.


----------



## b.lindsey (Apr 23, 2012)

Nice choice for a first engine Clive and a great little set-up you have there too...wish mine was as neat and orderly :big: 

Bill


----------



## Sshire (Apr 23, 2012)

Welcome Clive
I find that the most interesting aspect of this whole madness is devising ways to setup and hold parts. It's a wonderful mental exercise.
Keep at it. I made my first engine entirely on a mill since I didn't have a lathe at the time. Ask questions. You'll get responses from folks with years of experience who are anxious to help.
If you haven't found them yet, you might enjoy mrpete222 (aka Tubalcain) videos on Youtube. I believe there are more than 150 at this point.
Also the MIT machine shop videos have loads of useful tips.
Best
Stan


----------



## arnoldb (Apr 23, 2012)

Nice start on Elmer's wobbler Clive Thm:

On the Elmer's engines I've built so far, I just took the plans and converted all measurements to metric and jotted down the values on the plans. I noticed you also converted threads to metric; that's just dandy. I just look up the closest metric thread and substitute it. Rounding off to 0.02mm for the measurements are just fine in most cases, but I tend to round them to 0.01mm and try and machine to that.

Looking forward to your progress 

Kind regards, Arnold


----------



## purpleknif (Apr 23, 2012)

The fun is definitely in figuring out how to do it. The actual cutting is kind of a let down.


----------



## Blogwitch (Apr 24, 2012)

Clive,

A wonderful start into your journey of trials and tribulations. I just hope that you really catch the bug and carry on.

As you have most probably found out yourself, finding ways to actually get the shape you want is 90% of the exercise, and of course, if you do hit a problem, don't be afraid to ask, as I am sure there are many people on here that will have hit the same problem, and they will willingly share their knowledge with you.

Just keep up the good work, and don't rush things. Don't forget, make one good part at a time and you can't go far wrong.


John


----------



## lazylathe (Apr 24, 2012)

A great start Clive!!! ;D

Like you the problems i am having is how to hold/clamp things and the order of operation.
Having never done this before i can visualize the finished part and the steps required
to get there, just the order gets me everytime! ???

It is a slow process but as long as you are having a good time that is all that counts!!!

Looking forward to following you on your journey!

Andrew


----------



## clivel (Apr 24, 2012)

Thanks everyone for the great advice and words of encouragement  
If anything this forum illustrates what a wonderful sense of camaraderie and general helpfulness there is amongst this community.

@Alan, thanks for the beeswax tip definitely something to keep in mind for the future.

@Marv, the T-shaped guide for the milling table is an excellent idea. Although I do have a little indicator I had some difficulty in using the round bar lathe bed as a reference surface for the magnetic stand. I think in the end me getting the milling vice traverse parallel was more luck than skill. From looking at other builds it would seem that a better way to go would be to mount the indicator on rod held in the mill chuck. But as none of the attachments that came with my indicator seemed suitable I will have to try and rig up a better arrangement next time


----------



## clivel (Apr 25, 2012)

Once the frame and base were completed I decided to make the crankshaft bearing. Made from brass this proved to be fairly straightforward. This was successful at first attempt and although drilled, not reamed, it is a nice sliding fit on the 3/16" drill rod to be used for the crankshaft.






Emboldened by my success I expected the next part which was to be the crankshaft to go off without a hitch. But as they say pride goes before a fall.
Having previously decided that I could avoid learning the black art of tool grinding by sticking to indexable tipped tools, I mounted a RH tool in the toolpost, carefully checked it for centre height and then chucked up a short length of 3/4" cold rolled steel which was to form the crank disc.
A light skim off the face was met with disappointment. The surface was horrible - as rough as barbed wire. A skim along the length was no better, no matter how slowly I traversed the carriage or how light the cut, I just couldn't get a smooth surface.

I double checked everything was tight, I tried a straight tool, I tried faster, I tried slower, I tried with and without cutting fluid, but to no avail I just couldn't achieve a satisfactory finish:





Eventually after taking the lightest cuts possible, very slowly and then followed up with a file I managed to achieve a barely acceptable finish.

The bar was then transferred to the bench vice so that a slice could be sawn off. The plan was to reverse the chuck jaws to hold the machined side while the sawn face was faced to the correct thickness followed by drilling a central hole for the crankshaft.
But what I hadn't realised was that with the jaws reversed the chuck couldn't close down enough to grasp the disc. With the disc now too thin to grasp securely any other way I could see no other alternative than to remake it, but this time with the crankshaft hole drilled at the first turning.

However I didn't want to remake something and still be unhappy with it. There had to be a better way, so after a little research I decided to order a diamond tool holder.
When the tool arrived a few days ago I mounted the bit in the supplied grinding jig, turned on the newly purchased bench grinder and 30 seconds later had what appeared to be a correctly sharpened tool bit. I mounted the tool holder and bit on the lathe and using the same material as before proceeded to turn a new crank disc. I was stunned at the result. The finish was excellent. After turning to size, and drilling the crankshaft hole, the disc was fitted to the end the crankshaft with a dab of loctite.

Twenty four hours later, once I was sure that the loctite had set the crankshaft was grasped in a collet chuck so that the disc could be faced to the correct thickness:






Last night I fitted the crank pin, again with a drop of loctite to keep it in place, and this is the result:






Having it sitting on my desk all day I have been hard pressed not to give it the occasional twirl. Actually I have twirled it so many times, it's touch and go as to whether my thumb and forefinger or the bearing will wear out first 

Tonight I plan on starting work on the cylinder - a rectangular block of brass with a 3/8" bore. I still haven't figured out how I am going to bore it out, but a thought did cross my mind, and there is probably a very good reason why not to, but couldn't a two fluted 3/8" endmill be held in a tailstock chuck and used to plunge "bore" the cylinder?


----------



## ProdEng (Apr 26, 2012)

A two flute milling cutter is usually called a slot drill. The difference between a slot drill and an end mill is that the slot drill has a cutting edge on its face that goes all the way to the centre so it can drill; an end mill will not drill. Either way the result of using a milling cutter will be similar to using a drill, a hole that is not very circular and not particularly straight. For a cylinder bore we would like a hole that is parallel to the port face else the engine will probably lock up as the crank goes around. One answer is to use a boring bar to get within a few thou of size and then ream or lap to get a parallel bore with a nice finish. I usually drill close to size and then bore and lap.


----------



## thayer (Apr 26, 2012)

Hello Clive,

Welcome to the wonderful world of Elmer's Engines. I started the same as you, with his #25. My results are my avatar at left. Keep picking away and you will be done soon. I don't recall, but think I might have done as you suggest and used a 3/8 end mill for the final cut after drilling out most of the cylinder stock.

Here is mine in action.
[ame]http://www.youtube.com/watch?v=AcOpUwI-v70[/ame]

and the follow on, which honestly, I think took less time to build.
[ame]http://www.youtube.com/watch?v=NLKUff-7xZo[/ame]

Thayer


----------



## arnoldb (Apr 26, 2012)

Good going Clive Thm:

I'd advise against just plunging in only with slot mill held in the tailstock chuck. The brass will want to grab it and will easily pull the chuck out of the tailstock.

First prize would be to make up a boring tool, and drill and bore the cylinder to size. 
You can also make up a D-bit reamer; it's not difficult. The problem with the reamer is getting the last bit in the cylinder done, as there will be a cone left from drilling. You could simply drill and ream right through the cylinder, and then turn up a cylinder head and solder it in. If you're only going to run the engine on air (not steam) you can even Loctite the cylinder head on.

What you can also do is to drill the cylinder out to depth just under size with a normal drill. Then with the slot mill clean it out to size; run at high speed and feed in very slowly; take care on the last bit where the slot mill has to remove the cone left by the drill. Also when retracting, do it very slowly; that should leave you with a bore with a finish plenty good enough for this engine and no need to lap afterward.

Kind regards, Arnold


----------



## clivel (Apr 26, 2012)

Oh what lovely engines Thayer, and what a high standard to aim for 

Arnold & ProdEng, thanks for the advice. It seems that I really should try boring the cylinder the correct way - using a boring tool. And as I intend making the flywheel with a deep recess on the front, that will probably need to be bored as well.

I do have an indexable tip boring bar, but as it has a minimum hole size of about 12mm I will probably have to bite the bullet and try and make something smaller. In the book "Model Engineers Workshop Manual" George Thomas describes some small hole boring tools that don't look too difficult to make so I think that I will give one of his a try unless someone has a better suggestion.

When I get to making the flywheel I can picture how one would use a boring tool to turn the bottom and outer edge of the recess, but how would one normally turn the inner edge, a left-hand boring tool?






Thanks,
Clive


----------



## thayer (Apr 27, 2012)

Clive,

Thanks for the kind words. It was a lot of fun to build those engines and I am looking forward to doing another soon. As for the flywheel question, if there is room, I would just come into the hub area with a conventional RH cutting tool once you establish the inner face.

Thayer


----------



## clivel (Apr 27, 2012)

I spent the evening attempting a boring bar as per Geo Thomas's description.

I chucked a length of 1/4" drill rod in the four jaw chuck, offset by about it's diameter. I then turned down the middle bit for about and inch. Initially I found the eccentric turning quite alarming. I was convinced something would break, but I gritted my teeth and persevered:






(Sorry about the quality of the pictures, the camera just wouldn't cooperate tonight).

After removing the bar from the chuck I filed the tip flat to a fraction over half its diameter followed up by filing front and side clearance. I expected it to be a difficult job but it went surprisingly quickly. The filed surfaces were then finished off with emery cloth wrapped around the file.






At this point, it was far too late to start playing with fire, so tomorrow evening evening I will try hardening and tempering the bar. I just have to figure out what "cherry red" actually looks like.


----------



## clivel (Apr 27, 2012)

thayer  said:
			
		

> As for the flywheel question, if there is room, I would just come into the hub area with a conventional RH cutting tool once you establish the inner face.


Oh of course  thanks Thayer.


----------



## Maryak (Apr 27, 2012)

clivel  said:
			
		

> I just have to figure out what "cherry red" actually looks like.



Like a red cherry ;D

Seriously the above is pretty accurate but the colours are normally stated as being those you would see in daylight in a well naturally lit room. Not outside in the sunshine or in a dark dingy corner.

Hope this helps.

Best Regards
Bob


----------



## ausdier (Apr 27, 2012)

Just a quick model of the engine with a few little personal touches.
Hope you don't mind the post here on your thread.


----------



## clivel (Apr 27, 2012)

Thanks Bob 

That model is excellent ausdier, what software do you use?
I installed the trial version of Alibre but it was during a particularly busy few weeks so the trial expired before I had spent more than a few hours playing with it. But even that short time was enough to convince me that the learning curve is rather steep.


----------



## ausdier (Apr 28, 2012)

Thankyou clivel. 

I currently use either Inventor Pro 2012 or Solidworks Premium 2011.
This was done in Inventor. (which I prefer)
Not wanting to hijack this thread but if you want to see some of my work look here http://grabcad.com/darren.simpson


----------



## clivel (Apr 28, 2012)

Wow Darren, those are amazing   thanks for adding the link. 

It must have taken an enormous amount of perseverance to get to that level of expertise.

 :bow:


----------



## clivel (Apr 28, 2012)

Yesterday evening after work I hardened and tempered the boring tool. My wife was baking a steak pie for dinner, if she noticed the little tool being tempered in the corner of the oven while it cooked she never mentioned it 

After finding that the tool performed satisfactorily on a scrap of steel, I touched it up on a hone before using it to bore the flywheel recess. I had decided on a deep recess so that it could be held to the shaft via a grub screw through the hub.

The flywheel was screwed to a scrap of wood with a 45 degree mitre. After starting the hole with a tiny centre drill it was drilled and tapping for a 3mm grub screw.






More by luck than design, the hole came out in the correct place rather than breaking out the back of the flywheel.


----------



## Lesmo (Apr 30, 2012)

This is progressing very nicely Clive and looking good. As you can see there is plenty of advice on offer if you get stuck, my only advice, given my newbie status, would be to read back through the threads on this site as there is a goldmine of valuable information just waiting to be soaked up. Incidentally I too am a fan of the diamond cutter its rather expensive compared to indexable tools but well worth it for its simplicity to sharpen and keep sharp, not to mention the good finish you can achieve. Keep at it I will be following. 

Cheers Les


----------



## rhitee93 (Apr 30, 2012)

Nice work on the flywheel. It looks like the boring bar worked well.

I have used the oven for a number of "Off label" uses, but never while the wife was cooking in it. that takes it to a new level


----------



## bearcar1 (Apr 30, 2012)

'sneaking' a piece into the oven when old what's her name is preparing a meal ..........

The man has stones ...... nuff said.  STONES i tell you.
 ;D


BC1
Jim


----------



## clivel (Apr 30, 2012)

bearcar1  said:
			
		

> 'sneaking' a piece into the oven when old what's her name is preparing a meal ..........
> 
> The man has stones ...... nuff said.  STONES i tell you.
> ;D
> ...



Yeah ...
  and she keeps them in a bottle on the kitchen window sill


----------



## bearcar1 (Apr 30, 2012)

Rof}


At least you know there being stored safely and out of harms way ;D


BC1
Jim


----------



## clivel (May 6, 2012)

Unfortunately life had conspired to keep me out of the workshop for a few days, resulting in no progress until today when work began on the cylinder.

The plans called for a block of brass 1/2" x 5/8" x 1 1/8". Only having 5/8" square, I skimmed it to size in the 4 jaw chuck with the one pair of jaws reversed:





Next was drilling a hole large enough to get a boring bar in. Adjusting the 4 jaw chuck for centring the punch mark took ages, but the drilling itself took even longer, anything but the slowest feed of the drill would cause the lathe to jam and stall, even though I used a series of drills slowly increasing in size. I have read that one should smooth the cutting edge off the drill with a stone when drilling brass, but not being too sure what to smooth and only having one set of drills I skipped that step 
A bigger problem was judging how deep to drill to the correct depth. The tailstock dial was no use as I kept losing count of the number of turns, which turned out to be pointless anyway as the depth of the hole was slightly beyond the tailstock range. So in the end I put a dab of marking blue on the drill shaft and marked the depth on it - barely visible in the next picture.





As soon as the hole was barely large enough to accommodate the boring bar, using a clamp as a saddle stop, I bored the hole to the correct size with the little home made boring tool. This went really well, once it reached a fraction of a millimetre under size, without moving the crossfeed, I traversed the saddle back and forth a number of times. After which the size was spot on, and the finish appears to be silky smooth. Not having a reamer, I am hoping that this finish will be good enough.





Although purely cosmetic, as per the plans I turned the open end of the cylinder into a tube, and then bevelled the edges of the square with a file. I thought it would look more balanced if the closed end of the cylinder was also tube shaped, so turned that round as well. I was really pleased with the way the completed cylinder turned out as seen here:






But then, holding the cylinder in position against the frame trying to picture the completed engine, my heart sank into my stomach .......
In my enthusiasm, I had turned away the flat part of the cylinder where the port should go :redface2: 
so ... tomorrow I will have to remake the cylinder from scratch


----------



## ProdEng (May 6, 2012)

Sorry to hear about your trial but similar things happen to everyone 

The issue of drills for brass is explained nicely here by Deanofid http://www.homemodelenginemachinist.com/index.php?topic=6474.0. It works very well and I now have two sets of drills. Even if you buy just one additional drill for brass it will help a lot. Good luck with version two.


----------



## Groomengineering (May 6, 2012)

One thing you could do is turn up a couple of rings maybe 3/4" dia and loctite/solder them to the ends. Mill the face flat and viola, someplace to drill the port and an interesting spool shaped cylinder. ;D

I just hate to scrap brass for any reason. 

Nice work so far! Thm:

Cheers

Jeff


----------



## stevehuckss396 (May 6, 2012)

clivel  said:
			
		

> In my enthusiasm, I had turned away the flat part of the cylinder where the port should go :redface2:
> so ... tomorrow I will have to remake the cylinder from scratch



Done that!

When you get the part roughed to the basic size, use a sharpie to mark where holes and surfaces will be. It helps me from getting confused. Keeps me straight as to where the front or back is, where holes go ECT.


----------



## 90LX_Notch (May 6, 2012)

I agree with Steve. Been there done that. Sharpies are your friend.


----------



## thayer (May 6, 2012)

Clive,

Don't despair quite yet. There are a few options here. First, how much did you turn down on the sealed end? That will affect the plan of action.

The very first thing I would do is look at the geometry and consider if you can move the pivot point on the cylinder to accommodate a "new and improved" port location that aligns with the frame porting. No, you don't want the port coming through the cylinder wall partly down the piston at TDC, but nothing says you have to drill that port perpendicular to the pivot face to catch the top of the bore. If you decide to go this route, I would very carefully spot the port location with either a prick punch to catch a small center drill and/or use a 1/16 end mill to start the angled hole.

One complication is that you will also need to lengthen the connecting rod by the same amount that you move the pivot or the piston would not get anywhere near the end of the cylinder bore, greatly reducing the expansion ratio. As drawn the #25 has an ER of 17:1. Moving the pivot point .125 inches will drop that to 4.2:1. The piston will also protrude from the cylinder at BDC by the amount you move the cylinder block which may cause some binding near BDC. Simply extend the connecting rod by the same amount you move the pivot point to address this. 

Moving the pivot point will affect the running balance of the engine as well, but I wouldn't worry. My limited experience has been that these little engines all shake a bit anyway.

You could also turn and solder on an oversized sleeve and mill it flat on one side as suggested, or all 4 if you choose. With this approach the port could then again be drilled perpendicularly to the port face. The new part could be made from bar or plate stock. The seam would become a fine accent line once you cleaned up the joined parts. If you turned off enough, you could also leave a gap between the added part and the main cylinder body, effectively creating one large cooling fin on the cylinder head. That might look interesting.

Were it not for the issues of running aluminum against aluminum, I would say make it out of a piece of aluminum and press it place for a different look.

No matter what, I would first carefully draw the proposed changes based on the geometry of your part, either with CAD or to an enlarged scale with paper and pencil and find the new dims and angles to help sort out a plan of action. If you want some assistance with that I am pleased to do so. I have the #25 drawn in CAD so it would a snap to revise my drawings accordingly.

At the very least, don't scrap the part you have. Set it aside for later. I am sure that you could design a new engine around it after a build or two.

Keep the faith!
Thayer


----------



## ausdier (May 6, 2012)

Hi Clive.
I agree with Jeff's idea, I think it goes something like this ?
Live and learn, we all learn by our mistakes.


----------



## clivel (May 6, 2012)

Thanks everyone for the words of encouragement and advice.
My initial thought was to scrap the cylinder and start again. But after all the good ideas here I am going to at least try to salvage it before going that route.

ProdEng thanks for the excellent link, I am definitely going to try that the next time I drill brass.

Jeff and Thayer thanks for the thoughtful ideas and the excellent illustration by ausdier. It will be a few days before I will be able to to get back into the workshop so I have plenty to mull over in my mind in the meanwhile.

And last but not least, thanks to Steve's and 90LX's advice I stocked up on some sharpies today. Hopefully they will save me from too many more self inflicted learning exercises in the future


----------



## thayer (May 7, 2012)

One cool thing I noticed early on is that you can press a sharpie into the sherline spindle. I used this a few times during my early CNC days to do a rough layout on the stock and also check offsets were going in the right direction.

Thayer


----------



## Groomengineering (May 7, 2012)

ausdier  said:
			
		

> Hi Clive.
> I agree with Jeff's idea, I think it goes something like this ?
> Live and learn, we all learn by our mistakes.



Just like that, only I'd probably stop after step 2. ;D If you look at other Elmer V. engines he uses a lot of cyls with "rings" on the ends and square centers.

Cheers

Jeff


----------



## thayer (May 7, 2012)

You could even scribe a thin separation line and simulate a head that was bolted on with micro hardware. H 00-90 hex head or nut should be about .078 across the flats, so 6 of those on the end could look pretty cool. You would want an .035-in drill bit to tap the holes and a .052 for a close fit clearance. Personally I would go with the larger bit and a drop of CA on a toothpick to secure them. No need to be breaking micro taps.

www.scalehardware.com is one source for real and simulated nuts and bolts in micro sizes and Google turns up a bunch of others.

Thayer


----------



## Groomengineering (May 7, 2012)

Ooohhhh, little chrome acorn nuts would be slick. ;D

Cheers

Jeff


----------



## clivel (May 9, 2012)

The little nuts and bolts are a nice idea, but I need to ease up on the creativity, that was what got me into trouble in the first place 

 ... so taking the more conservative approach, I opted for fitting a ring around the end of the cylinder.
 But after rummaging through the meagre contents of my scrap box and not finding any suitable material, it dawned on me that all that is required is a small filler piece wide enough to cover the port holes in the frame when the cylinder is rotated to top and bottom dead centre.

I hacked off a little chunk of brass from the remaining piece of bar that had been used for the cylinder and then filed a little half round indentation until it was a close-ish fit to the end of the cylinder.
I thoroughly cleaned both the cylinder and filler piece with alcohol before carefully applying flux to both parts with a tooth pick. Not too sure of how to hold the structure together for soldering my eyes fell on some stranded picture hanging wire which was easily hand twisted to hold the parts together. Three tiny pieces of silver solder were placed at the joints, the propane torch lit, and the cylinder gently heated. Nothing happened. Being over cautious and never having used silver solder before, I had the torch turned down far too low. I slowly turned it up and then in an instant the solder liquefied and as if by magic was sucked into the joints.
Here it is cooling down, the rough looking projection at the back is the filler piece that started out far too thick:







I was a bit disappointed when it cooled down, I hadn't expected it turn out quite so messy, but nothing ventured, nothing gained, so I dropped it into some citric acid solution and left if for a few hours. After which, other than being a little duller, it looked as good as new again 

I then skimmed the back of the cylinder in the four jaw chuck to level the filler piece flush with the back:







Followed up by skimming the bearing face, and then fitted the pivot pin:






Current state of play - waiting for piston, connecting rod and airline barb:


----------



## ProdEng (May 9, 2012)

Well done with the repair, it looks good and you have a unique cylinder


----------



## rhitee93 (May 9, 2012)

Nicely done. If you ask me, it looks like it was supposed to be that way. Thm:


----------



## b.lindsey (May 9, 2012)

Nice save Clive...as already noted...look like it's supposed to be that way. The project is coming along quite well and I am still following along with interest!!

Bill


----------



## thayer (May 10, 2012)

Clive, that really looks the part and quite honestly, it is rather more elegant than the solutions I was envisioning as well!

Thayer


----------



## Groomengineering (May 12, 2012)

Very nice save! Thm:

Cheers

Jeff


----------



## clivel (May 16, 2012)

The lovely spring weather of the past few days had one unfortunate side effect. By managerial decree I was presented with a box of seedlings and banished to the wide outdoors for a spot of gardening. But in the end, with fresh mud still under my finger nails I managed to grab a few hours to myself which I spent in the workshop.

First task was the piston rod seen being turned here. I left it long enough for the little bulge closest to the centre to be removed prior to threading 3mm. The thicker part closest to the chuck was destined to be cross drilled for the crank pin.






To say that the cross drilling was not too successful is an understatement. I aligned a far too large V-block under the drill. The little piston rod was dwarfed by the stirrup clamp and the only way I could get it fixed in place was by interposing a piece of scrap between the clamp and the rod in Heath Robinson fashion. Needless to say something slipped once drilling started and the drill entered off centre. When it grabbed on exiting the piston rod freed itself from the clamp. Attaching itself to the drill bit it did a remarkable impression of a Sikorsky chopper. It seemed about to take off by the time I managed to hit the power switch. Fortunately no injuries and no damage, not even to the bit.
There is definitely something to be said for beginners starting with low powered machinery :hDe:

Next I decided to make an airline barb. After looking at pictures I was somewhat puzzled as how to turn the taper on each segment when it dawned on me that a tool of the correct width rotated to the desired angle could be plunged straight in which is what I did with a parting tool:






Buoyed by my success with the barb, I milled the sides of the piston rod flat and assembled the engine which can be seen here, now almost complete except for one last item, the piston.






Not obvious from the photo is just how off centre the crank pin hole in the piston rod is. It is definitely going to have to be remade, but as I am keen to see the engine (hopefully) working, I think I will do the piston first and replace the rod after that.


----------



## vcutajar (May 16, 2012)

Clive

Slowly but surely you are getting there. Keep it up.

Vince


----------



## clivel (May 18, 2012)

Thanks Vince


----------



## clivel (May 18, 2012)

Last night I made the piston. 

Turning it down to size was a fairly protracted experience because somehow I just can't seem to get consistent readings with the digital calliper when measuring a diameter - no two readings are the same. It is not the calliper it is me 
So to ensure that I didn't make the piston too small, once it was close-ish to size I progressively reduced it by taking cuts of half a division - 0.025mm checking against the cylinder between each cut. When it was only just too large to go into the cylinder I switched to a parting tool for the oil grooves. After which I slowly reduced the piston diameter by wrapping a loop of emery cloth around it while rotating the lathe at high speed until the piston slid smoothly into the cylinder.
As a result the piston now appears to be a nice close fit, dropping it vertically into the cylinder while covering the inlet/exhaust hole causes it to descend very slowly, unblocking the hole causes it to drop rapidly.

Here the piston has been drilled threaded and attached to the piston rod:





Clearly visible in the photo is the badly offset crank pin hole.
Undeterred by this "cosmetic" blemish I assembled the engine all ready for its first test run. But I was disappointed to find that the engine binds at one spot when rotated. After checking the crank pin and crankshaft for squareness, I guess the off centre hole is the most likely culprit. So the engines maiden voyage will have to be postponed until after I make a new piston rod, hopefully this weekend.


----------



## mklotz (May 18, 2012)

Calipers are the wrong tool for measuring diameters on the lathe. Get a micrometer and you'll get more accurate and more repeatable measurements.

Not to be a nanny but since you're a self-admitted novice...

Be very, very careful when using emery strips on the lathe. Wrapping them completely around the work can easily trap a finger and do you great damage. Never wrap a loose end around any part of your anatomy. 

Far better is to wrap the emery strip over a stick or a file and use that as a very fine file on the work. One simple and cheap method is to use a piece of yardstick or a wooden paint stirrer and two binder clips.


----------



## clivel (May 18, 2012)

mklotz  said:
			
		

> Not to be a nanny but since you're a self-admitted novice...



That isn't being a nanny, it is excellent, and most welcome advice, thank you 

and thanks for the tip on the micrometer, I hadn't really considered one as I had naively assumed that the modern digital calliper was a catch all replacement for most measuring instruments.


----------



## mklotz (May 18, 2012)

Calipers need technique to get accurate measurements. Practice with a micrometer standard or a gage block/pin - something with a precisely known size. The jaws must sit flat on the work and pressure is applied directly to the jaws using two fingers - not the little roller thing for moving the movable jaw quickly.

Naturally, the jaws must be scrupulously clean. Even with all these dicta observed and assuming high quality calipers like Mitutoyo, you'll be hard pressed to measure more accurately than a thousandth.


----------



## Lesmo (May 19, 2012)

Nice recovery on the cylinder Clive. Whilst the recovery advice given was excellent its always nice to be able to come up with your own solution to the problem and it looks as it was meant to be like that. Good one.

Cheers Les


----------



## clivel (Jun 22, 2012)

Well I hadn't quite abandoned my build 
More like a broken lathe drive belt had put my machinist ambitions on hold for a few weeks.
The lathe uses off the shelf timing belts but the particular sizes and pitch can't be too popular as I had a really hard time getting hold of these. After I eventually found a US company willing to actually mail a few of these tiny belts to Canada in a padded envelope, I then gained first hand experience at just how inefficient the US postal service is. It took nearly three weeks for the envelope to arrive. In contrast tools and other items ordered from the UK with comparable shipping costs typically arrive in four to five days.

Once the lathe was up and running, the first thing I did was to remake the piston rod. This time taking a considerable amount of care to ensure that the crank pin hole was centralised. Once the new rod was fitted, I was pleased to find that any hint of binding had disappeared and the engine now turned over smoothly.
Not having a source of compressed air, I had to wait until last night when I visited a friend with a compressor to try it out and was stunned to find that it WORKS !!! :big: :big:

Here the completed engine:




Although my engine is far from perfect, and I made a number of mistakes along the way, I think this only added to what was an incredibly valuable learning experience.

What's next ?
Having followed so many of the excellent builds on this site, paying particularly note to the set-ups and procedures used by others, I have it in mind to try and improve the workshop facilities by making a few tools.
To start out, I spent the last two evenings making a centre finder to a design published in "Model Engineer" a few years back. Here it is, the individual pieces, and then assembled:


----------



## 90LX_Notch (Jun 22, 2012)

Clivel-

Congrats on your first runner. Well done.

-Bob


----------



## arnoldb (Jun 22, 2012)

Thm: Well done Clive ;D

Your engine looks just dandy, and you handled the little set-backs along the way really well 
It's the learning experience and fun along the way that really counts - as I'm sure you found out 

I'm raising a glass to you right now; Bottoms Up *beer*

Kind regards, Arnold


----------



## ProdEng (Jun 22, 2012)

Good job getting your engine going Clive, watching an engine run is the best encouragement. The centre finder is a tool I can't do without and the first one I made. Will be interested to see what engine you chose next.

Jan


----------



## rebush (Jun 22, 2012)

Clive: Congratulations on an engine up and running. It's a great feeling. Must be something in the air like Jan and yourself a center finder was the first tool I built also. I'm sure you've already got a few plans that you'd like to do next. What'll it be? Roger


----------



## bearcar1 (Jun 22, 2012)

Well done Clive and nicely executed. woohoo1 Thm:

BC1
Jim


----------



## clivel (Jun 25, 2012)

Thanks for the kind comments everyone 
Clive


----------

