# Three cylinder Radial



## Russel (Nov 4, 2009)

I have started my first complicated project. I have done a little wobbler, and a few simple odds and ends, I think it is time to dive into a more advanced. I decided to build a three cylinder radial engine. If you follow the this link and scroll down to engine 11, that is the one.

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

I decided to start with the crankcase. I figure that it is going to be the most difficult part for me to make. Hopefully, things will get easier from there. 

The day before yesterday, I believe, I cut the basic stock and faced the two ends for the crankcase:






Yesterday, I bored out the inside of the case and drilled and reamed the quarter inch hole in the back.





Today, I had a little mishap with the DRO wires on my Sherline 2000 mill, so I didn't get the turning fixture completed. But, I did get the milling done on it so I can start with the lathe tomorrow.

If you are interested in my little mishap with the DRO wires follow this link:
http://www.homemodelenginemachinist.com/index.php?topic=6619.0

Anyway, here is what I got done today:




 I'll post more as thing progress.

Russ


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## Deanofid (Nov 4, 2009)

You're headed in the right direction, Russ. Getting started is sometimes the biggest step.

Dean


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## cfellows (Nov 4, 2009)

Great choice! I've been tempted to build that engine for some time now. Metal Butcher built a customized version of this engine. Here's the thread.

http://www.homemodelenginemachinist.com/index.php?topic=4364.0

Chuck


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## Russel (Nov 4, 2009)

Metal Butcher did an amazing job on his radial build. I hope I can make one that looks as good!

It's nice to get an idea what the parts really look like. The plans have photocopied photographs in black and white that aren't very clear. Metal Butcher's radial engine posts are a good motivating factor for me!

Russ


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## Russel (Nov 5, 2009)

I didn't get much time to play today, but I did get a little done on the turning fixture. I tried and tried, but I couldn't get the turning fixture straight flat against the four jaw chuck. I could center it, but couldn't get the back square toward the headchuck. So, changing gears in my head, I decided to use a faceplate. Man, what a difference! I marked, drilled and tapped holes in the faceplate to hold the part. Then put the faceplate on the lathe and gave it a couple light passes with the cutting bit to true it and screwed down the part. Worked like a charm. I just spent more time than I thought it would take to rig it up. Anyway here are the photos:

Here with the not so perfect four jaw chuck:





and here a close up of the faceplate with the turning fixture mounted on it:


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## Deanofid (Nov 5, 2009)

Russel  said:
			
		

> Worked like a charm. I just spent more time than I thought it would take to rig it up.



This is the life of the machinist, Russ. Setting up is often the bigger part of the job. Many times it an hour and a half dialing in and squaring the job for a 10 minute cut. 
I'm surprised you had trouble with the Sherline four jaw. I had one at one time. Was a well built piece of kit.
You usually can't go wrong with the face plate though. Face it off and you know it's square!

Keep up the good work!

Dean


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## Brian Rupnow (Nov 5, 2009)

Looks like a neat project. I did some serious studying on Elmers 3 cyl. radial to figure out how all those connecting rods met on a common hub before I designed my 5 cylinder radial engine.---Brian


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## Russel (Nov 6, 2009)

Deanofid  said:
			
		

> ...I'm surprised you had trouble with the Sherline four jaw. I had one at one time. Was a well built piece of kit....



The chuck works great for long parts, or parts that you can mount right against the face. But the one I have seems to have about .0015" difference in the height of the jaw steps. To be honest, I thought the chuck was the easy answer and that the face plate was an old outdated part of the lathe. Through my own recent experience I have learned that the face plate is a very useful part of a lathe system. (I see custom faceplate plans forming in my head.) Just like turning between centers with a dogleg. I thought that was outdated by the chuck until I needed to lathe stuff with as much precision as my little Sherline lathe could muster. I learned respect for turning between centers that day. Experience is a good teacher.


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## Deanofid (Nov 6, 2009)

Oh you bet! Turning between centers is the way to go at it if you want straight shafting. Great for when you need to do work on both ends of a piece too.  You can flip a piece over and over and know it will be on centers every time. 

Sherline has a follow steady that they sell for their lathes that will come in very handy for you if you are going to turn long pieces of round stock. Lots of neat stuff in their catalog to try to find a use for..


Dean.


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## Russel (Nov 7, 2009)

Today I got the flats of the crankcase machined. I don't know if I did it the best way, but the method I used seemed to work well enough. Instead of using a locating pin and machining the flats with a lathe I used a CNC rotary table. Lots of set up here! mount the RT to the vertical support and align mount the vertical support to the table and align Y axis and Z axis. Use a DTI on the round part of the rectangular turning fixture and center it on the RT. Then I made X axis passes in three stages with a final pass slightly cutting into the turning fixture to catch the little bits that the X axis passed didn't get. I'm tired, but happy!

Here is my humble little milling setup:





Here is a little closer so you can see the CNC RT:





And finally, a close up of the crankcase still mounted to the turning fixture:


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## cfellows (Nov 7, 2009)

Nice work, Russel. Lots of work, but a job well done!

Chuck


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## zeeprogrammer (Nov 8, 2009)

Nice project and thread! Keep the pics coming.


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## Metal Butcher (Nov 8, 2009)

Russel  said:
			
		

> I'm tired, but happy!
> 
> MB wrote:
> 
> ...


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## Brian Rupnow (Nov 8, 2009)

For what its worth---This is the model I built of the engine you are working on when I was figuring out how the con-rods all ended on a common "plane" when I was designing my radial.----Its not complete---just layed in enough stuff to study the part I was interested in.----Brian


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## Russel (Nov 9, 2009)

Thank you for the encouragement everyone! 

Brian, that's a cool 3D model of the engine.

Well, I managed to get a little done today and learned a little in the process. I think I have the Sherline boring tool worked out.






One problem I had was keeping the lower part of the boring tool in contact with the cutting adjustment screw. I solved that by using a newspaper rubber band to hold the lower part again the adjustment screw. Worked like a charm. My left hand on the Allen (hex) wrench to unlock and lock the lower part of the tool and my right hand to turn and hold the adjustment while locking the setting. The other problem I encountered is that the adjustment screw would unscrew many turns while the tool was in use boring the hole. So, I used another rubber band to hold the adjustment screw and keep it from unscrewing while the boring tool is cutting. One other problem that I encountered before was an inconsistent adjustment from the screw. I solved this problem a while back by drilling and tapping a block of brass and using that as a jig to make the end of the screw flat. Originally it was concaved with an inconsistent surface.











Not that I have figured out these little enhancements, I am very happy with the consistent results that I get boring a hole with the boring tool. Up to today, getting a hole the size that I wanted seemed elusive enough that I prefered not to use the boring tool unless I absolutely had to. Now I feel confident I can machine a hole to within a thousandth of and inch. I spot drilled the cylinder bore in the crankcase then drilled it with a small drill bit, just about as big as the flute width of a half inch drill. Then, carefully, at about 200 RPM, I drilled the case with a sharp half inch drill. Afther that the boring tool finished the job to the required size.

In order to tap the threads for the cylinder mounting screws, I made a 1.15" diameter tapping handle for the tap and used the drillchuck as a guide for the back of the tap. I also made a small cutting oil applicator, much like a watch oiler only bigger, to apply cutting oil to the tap while tapping without flooding everything with oil.






Here is the crankcase with one of three sides bored, drilled and tapped....two more to go.






You can see a couple of minor screw ups that I did in this last photo. I used a center drill that was too big to spot drill the bottom right cylinder mount screw. Not a real problem, there are plenty of threads deeper in the hole. If I have to, I can repair it. And the lower left edge between the side I bored and it's adjacent side you cans see where I didn't back out the endmill enough as I advanced the RT to the next facet while machining the flats the other day. As I invest more time in this part I find myself triple checking everything...I don't want to start over now! Anyway, two more side to drill tap and bore, then three holes to drill in the end and I'll be ready to start the next part.

Russ


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## Deanofid (Nov 9, 2009)

You're getting along nicely, Russ, especially since you had tool troubles.

I had a little airplane once that ran on a rubber band. I didn't know they made boring heads like that too!

Dean


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## zeeprogrammer (Nov 9, 2009)

Great pics Russ. Believe it or not...I think they're very helpful to us newbies.


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## Russel (Nov 10, 2009)

Deanofid  said:
			
		

> You're getting along nicely, Russ, especially since you had tool troubles.
> 
> I had a little airplane once that ran on a rubber band. I didn't know they made boring heads like that too!
> 
> Dean



Thanks, we learn from our mistakes!

It's kind of funny because it's not the tools problem that I don't have three arms. But, the rubber bands did the trick...good for little air plains, and Sherline boring tools. (Oh yeah, good for the morning paper too.)



			
				zeeprogrammer  said:
			
		

> Great pics Russ. Believe it or not...I think they're very helpful to us newbies.



Hey, I'm one of those newbies! I've learned quite a bit from the posts, especially with photos, so I figured I would do my part and post things with this little engine as they develop. That way maybe the next guy won't make the same mistakes as me. Besides, you guys are great motivators!

Russ


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## Russel (Nov 10, 2009)

Got another side of the crankcase ready for a cylinder. Things when much quicker that the other day when I was playing with rubber bands and making a tapping handle for my 2-56 tap. I am really enjoying this now that I feel like I have a better handle on my little machine tools.

Anyway, here is a photo of the tapping handle, ready to tap a 2-56 hole. The tap is loose in the drill chuck so that the chuck acts like a guide. 






After drilling and tapping the cylinder mounting holes and steam port, I drilled the case for the cylinder to a half inch so that I could use the boring tool. The 4 Jaw self centering chuck comes in handy in this operation.






The setup almost looks comical. I find that if I pre-drill a hole just about the size of the flute thickness on the half inch drill bit, and use a good sharp 1/2" drill bit at about 150 to 200 rpm I get pretty good results without overworking my little machine.











I was so pleased with the smooth progress today that I felt the need to clean the crankcase and take a more aesthetic photo:






One more side to bore drill and tap...


Russ


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## joe d (Nov 10, 2009)

Looking good, Russ.

I know that I always enjoy it when a part starts looking like a part instead of raw material :big:

Cheers, Joe


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## Deanofid (Nov 10, 2009)

Still moving right along, Russ. It's looking good.

The small hole you drilled in the crankcase, followed by the larger drill bit is the norm for many of us, especially those of us with small machines.  (The little hole is called a pilot.)  Often the pilot will help the larger bit make a straighter hole. There's some controversy about that, but I usually drill a pilot when I have a large hole to drill. Yeah, it does look kind of funny.

I have a suggestion, but please don't take it as criticism. In the interest of safety, you should ditch those rags you have covering the lead screw, or whatever you are using them for. One stray chip off that drill bit will grab that rag and suck it into the works so fast you won't know what happened. In doing so, it will fling chips all over your shop, and on you, and the rag whipping around can do quite a bit of damage when it catches on something, (like the work piece, or worse, a finger). 
Just a thought.

You can use heavy construction paper to make gaiters to cover those lead screws, and it won't pose any safety issues.

Keep up your good work! Thanks for sharing the build with us.

Dean


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## Russel (Nov 10, 2009)

Dean,

Suggestions and criticism are always welcome! You are correct, I really shouldn't have shop rags that close to the action. Even with the little machines that I am using I have seen some pretty long chips! I will take your advice and use construction paper, or maybe paper towels, to cover the lead screws until I get a chance to make some better accordion covers. 

Thank you for the safety tip!

Russ


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## Deanofid (Nov 10, 2009)

Russ, paper works pretty well, and is easy to work with. You can buy them too. I've seen them a few places on the web. Maybe at Little Machine Shop.

These are about six months old on my little Taig mill, similar in size to your Sherline. Can't see the back one, but is the same as the front.







Dean


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## Twmaster (Nov 10, 2009)

Bellows cover:

http://www.littlemachineshop.com/products/product_view.php?ProductID=1431

or 

http://shorterlink.org/6329


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## Russel (Nov 10, 2009)

Thank you Deanofid and Twmaster! I found this video on folding a bellows, but wasn't sure what to use for material. Now I know where to get the material.

[ame]http://www.youtube.com/watch?v=EV-eHIGzMPg[/ame]


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## vascon2196 (Nov 11, 2009)

Nice job with this engine! This is yet another engine I've been wanting to build but only modeled it and animated it in SolidWorks.


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## Russel (Nov 11, 2009)

Well, more of the same today. I finished one more "facet" of the crankcase. Nothing you haven't already seen. Everything went very well and I enjoyed myself confidently drilling tapping and boring. 

Following Deanofid's advise, this time I didn't use a shop towel to cover the lead screw. I made some bellow covers out of regular 8.5" by 11" paper. The funny thing is that it is not only safer (check out those chips in the photo) it worked much better at keeping the leadscrew clean! Thank's Deanofid!

Russ


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## Metal Butcher (Nov 11, 2009)

Very clever! They are also very simple and inexpensive to replace!

I have chip deflectors on my lath, mill, and band saw made of corrugated cardboard!

Their not much to look at, but they work great!

-MB


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## Russel (Nov 18, 2009)

It has taken me a few days to get back to this project. You know how those little side projects pop up sometimes.

Today I drilled and cut threads for the foot of the crankcase.





Then drilled the steam ports that connect with the cylinder steam ports.






Then, and this took the most time, I mounted the rotary table to the mill table, mounted the crankcase jig that I used before and with the help of a DTI centered the jig to the rotary table. Then I mounted the crankcase to the jig with a single 10-32 screw in the middle and centered it to the rotary table with a DTI. When that was done I used the DTI to sweep one of the case facets with the DTI to align the side of the crankcase with the mill X axis. I set up 6 divisions on the CNC rotary table controller and proceeded to center drill, drill and tap the crankcase cover screw holes.
















So far, that's 18 2-56 holes drilled and tapped and 2 5-40 holes for the base. Only 6 more 2-56 holes to drill and tap and the spot for the vent.

Russ


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## zeeprogrammer (Nov 18, 2009)

That looks great Russ.
I sure hope you didn't jink things with that last statement about 'only 6 more 2-56 holes'. :big:
Did you make that 'handle?' for the tap?


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## SBWHART (Nov 19, 2009)

Hi Russel tracked you're radial build down.

Great work

Stew


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## Russel (Nov 19, 2009)

zeeprogrammer  said:
			
		

> That looks great Russ.
> I sure hope you didn't jink things with that last statement about 'only 6 more 2-56 holes'. :big:
> Did you make that 'handle?' for the tap?



Thank you for the praise. Tapping the holes isn't really difficult, just very time consuming. I made the tap handle disk earlier in the project with my lathe and bench drill press. At the time I had the crankcase carefully mounted on the mill and didn't want to disturb it. The other day, while I had the rotary table squared up on the mill, I was looking for anything else I could machine with it and gave the tap handle disk a little embellishment. I've use the thing almost enough (it seems) to polish it with my skin! The new grip works well and using the 1/4" drill chuck as a guide keeps everything straight, so I'm not concerned about jinksing myself. (Oops, there I go again!)



			
				SBWHART  said:
			
		

> Hi Russel tracked you're radial build down.
> 
> Great work
> 
> Stew



Thank you Stew! I'm almost done with the first part.


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## NickG (Nov 19, 2009)

Russ that really is going well, great photography too

Nick :bow:


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## Deanofid (Nov 19, 2009)

Nice documentation, Russ, and the crankcase is looking good!
That's quite a few tapped holes for one piece. Hold your mouth right..

Dean


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## Russel (Nov 23, 2009)

Thank you for the kind words gentlemen. 

I've gotten a little side tracked with some small tool projects and such, so it has been a few days since I've worked on the little radial. I spent a couple hours working on the crank case today and finished the drilling and tapping with the exception of the vent. I am going to move on to some of the other parts after today and leave the finish (bling) and vent for later. I wanted to complete the most difficult tasks on the most complicated part and I think I have done that. So, here is the case with the valve side case holes drilled and tapped. I won't bother to explain the process because it is basically the same as when I did the other side of the case earlier.

Here it is still in the jig.





The threads look pretty good. It's not like I've had any practice or anything 





Here is the crankcase:










More to come...


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## Artie (Nov 24, 2009)

Russel, watching with interest and waiting (impatiently) for more. Looks good mate keep it going... Artie


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## Deanofid (Nov 24, 2009)

It's looking very good, Russel. The tapped holes are just fine. Almost any tapped hole that doesn't have a tap broken off in it looks good!

Keep it up!

Dean


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## Russel (Nov 25, 2009)

Deanofid  said:
			
		

> It's looking very good, Russel. The tapped holes are just fine. Almost any tapped hole that doesn't have a tap broken off in it looks good!



That's true! 

It's just that it got to the point with this part that after tapping the first dozen 2-56 hole, I felt like I should bring a book to read while I was doing it. 

I was planning to start on the crankcase covers today, but ended up doing some much needed cleaning and reorganizing in the shop. When that was done I was ready for a beer. I should be working on the covers tomorrow.

Russ


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## Russel (Nov 25, 2009)

I got started on the crankcase cover today. First I hack sawed off about a half inch of 1.75 aluminum rod.






Then, I put the most flat end against the chuck and faced one side.






Then center drilled and drilled for a 10-32 screw to go through it. I am going to make a bushing for the quarter inch shaft that will pass through this part. In the mean time I just need a center hole to hold it up against a jig so that I can machine it. So, I face the other side up to the fastener that is holding it to the jig.






Then machine the part that fits into the crankcase. Then take it off the jig, mount it to the chuck and face the center where the fastener held it to the jig.






I flip it over, mount it back to the jig and machine the other side.






Then, after cleaning oiling and putting the lathe back on it's shelf, mount the cover to the RT on the mill using the original crankcase jig and zero it in.






I centered the part with a edge finder, set the X axis offset and programmed the CNC RT controller for 6 divisions. Center drill, drill and bevel the edges on the holes and Ta Da! After spending days on the crank case, I can hardly believe that I almost finished a whole part today. It just need the bushing machined out of brass and the center of the cover bored for the bushing.











It's starting to look like something! More to come...

Russ


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## Deanofid (Nov 26, 2009)

Looks real nice, Russ. Lovely.
Nice old Starret DTI, too. Or maybe it's new. They haven't changed much!

Dean


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## Russel (Nov 26, 2009)

The DTI is a few years old and hasn't been used very much until recently. I sure do love Starret tools! Some of the Starret stuff is overpriced like their venier calipers, but the DTI and the edge finder I have are bargains considering how well they work. Needless to say, they are well cared for.

Russ


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## NickG (Nov 26, 2009)

Nice work Russel.

I have a set of Starret vernier calipers that my grandfather gave me - god knows how old they are. They are good put a pain to use compared to modern digi ones! Think I have a 1-2 starrett micrometer too that was picked up for a couple of squid from a car boot sale!

Nick


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## Russel (Nov 26, 2009)

I've had people ask me why I use a vernier caliper instead of a dial or digital caliper. I just like the fact that a vernier caliper is very durable and doesn't require a battery. Now that I'm beginning to use my machine tools and actually make things, I find the vernier caliper quick and easy to use. 

A lot of what I have learned here is that your brain is one of a machinists most important tools. I find myself planning how I am going to make a part, constantly consulting the calculator for working out dimensions (some of that is starting to happen in my head without the need for the calculator), figuring out how much potential error is present in my method and how much accuracy I really need. Compaired with that, using a vernier is childsplay. But, I didn't always think so.

Russ


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## Powder keg (Nov 26, 2009)

I like Vernier calipers because you can "see" how much further you need to go. You don't have to add or subtract anything in your head or on a calculator.

Engine is looking nice!!!


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## Metal Butcher (Nov 26, 2009)

Russel  said:
			
		

> I've had people ask me why I use a vernier caliper instead of a dial or digital caliper. I just like the fact that a vernier caliper is very durable and doesn't require a battery. Now that I'm beginning to use my machine tools and actually make things, I find the vernier caliper quick and easy to use.
> Russ



Hi Russel, you project is coming allong extremely well.

I had a vernier caliper in my collection of tools. I couldn't use them very well due to my bad eye sight.

My next set were dial calipers that read 0-100-0, spacing was a little small and I didn't care for them all that much.

My third set was a 0-100 and I liked them the best. Unfortunately a hammer fell of its perch and annihilated those.

My present set of calipers are inexpensive import digital (LCD). At first I didn't care for them all that much, and I missed watching the needle circling the dial. But after a few weeks of use they became a part of me and I don't think I would go back to using a dial caliper. Yes, the battery needs to be replaced, but they are inexpensive if ordered online. They do offer some nice additional features. With a push of a button the become metric calipers and also provide exact conversion. With the "zero out" button they do handy calculations.

Use the tools that you feel comfortable with, and don't concern yourself with being pressured to use a tool or techniques that doesn't suit you.

I use paper and pencil. I been told many times "why don't you use a calculator". I prefer to use pencil and paper that will leave a trail to follow. With a calculator there is no trail and I make entry mistakes caused by again poor eyesight.

The goal here is making accurate parts and assembling them to make a running engine, and there are many ways to reach that goal

-MB


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## Twmaster (Nov 26, 2009)

Like MB I too use a digital caliper as my eyes are also going to hell and tiny little tick marks are really hard for me to read on small mikes and things.

It doesn't matter whether you use a yard stick or a Starrett micrometer. As long as your project ends up the way you want it.

Your engine is coming along nicely. Bravo!


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## cfellows (Nov 26, 2009)

Really fine work, there, Russell. I really like what you're doing here.

Chuck


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## Russel (Nov 27, 2009)

Thank you for the compliments, Dean, Nick, Power keg, Metal Butcher, Twmaster, and Chuck! I am really enjoying this project! 



			
				Metal Butcher  said:
			
		

> I use paper and pencil. I been told many times "why don't you use a calculator". I prefer to use pencil and paper that will leave a trail to follow. With a calculator there is no trail and I make entry mistakes caused by again poor eyesight.
> 
> The goal here is making accurate parts and assembling them to make a running engine, and there are many ways to reach that goal
> 
> -MB



Yes, the one drawback of using vernier calipers is that I need reading glasses and/or a magnifier to read them. Of course, I need some magnification to see what I'm doing with the machine tools also, so no "extra" equipment is required.

I use a calculator quite a bit, but I also repeat calculations sometime to be sure that I remember the number correctly...no paper trail. 

Reading some of Bogs posts, I ran across one where he mentioned that he writes down cuts as he goes sometimes to keep track. Well, after cutting too much a couple times I started doing that and found it a great help, especially if you are getting interupted sometimes.

Pencil and paper isn't a bad method. 

Russ


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## Russel (Dec 9, 2010)

Wow! I had to dig a little to find this thread. My apologies, it has been over a year. It is amazing how sidetracked you can get at times. I haven't abandoned this project, just sidelined it for a while.

Anyway, I've machined the cylinders. I didn't take photos during the machining process, but here is the cylinders after machining. I think the cylinder heads will be next. More to come, soon...


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## Blogwitch (Dec 9, 2010)

Russ,

This engine is a slightly different take on Westbury's Cygnet Royale. Stew built one of those a while back, and I built the same one from castings a few years earlier, and if care is taken, they are so smooth while running, there are hardly any vibrations at all. They WILL reverse, after a fashion, if you make up a control valve to swap over the inlet and exhaust. Easily done after you get the engine running.

With regards to using notebook and pencil, I use them all the time to keep a check not only of what I have done, but before I even start to cut, I usually plan and write down the whole cutting sequence beforehand. Then once I go thru it a couple of times and double check things as I go, when I actually come to do the cutting, it is like I have done it all before, and things go very smoothly indeed. This is a very handy system to use if you have to make multiple parts, you always know which stage you are up to, and all the parts come out the same. The only trouble is if you get your calcs wrong, you can make multiple bad parts, all having the same fault. I have never done that yet, but I can guarantee it will catch me out one day.

Yours is coming along very nicely indeed, and I am sure you will end up with a great running engine.


Bogs


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## Russel (Dec 9, 2010)

Hello Bogs,

I never knew of Westbury's Cygnet Royale, but after looking it up on the internet, I have to agree that the radial I'm machining is very similar. I'm using plans from john-tom.com, the Elmer's engines page, the #11 Radial. I really like the reversing valve on the Cygnet Royale! I may have to add one to my little project.

It is kind of ironic that you mentioned using a notebook and pencil in reference to my older post because after having to start over, machining a couple parts this last year, I have gotten into the habit of using post it notes to keep track of calculations while machining. It seem like once I got started using simple notes to keep track of the numbers the whole process got easier. Best of all, I don't find myself re-calculating because I forgot a dimension.

Russ


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## ruzzie (Dec 9, 2010)

Hi All
Here is a Cygnet I finished earlier
http://www.homemodelenginemachinist.com/index.php?topic=11191.msg122488#msg122488

"http://www.youtube.com/v/E_UTqFTS-VM&hl=en_US&feature=player_embedded&version=3"
Cheers 
Paul


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## Russel (Oct 11, 2011)

Wow, I started out OK, but it is really taking me a long time to complete this project!

Anyway, I figured out how to calculate the cuts to make spokes on a flywheel. So, I made the flywheel for this little radial engine. One thing that I found helpful, an extra fine sharpe fits into the spindle my sherline mill. That allows me to check the cutter path on the part before removing metal.


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## thayer (Oct 11, 2011)

Nice looking parts Russel. FWIW, I have used my mill as a plotter as well, though with a conventional fine sharpie. Black for the part outline and red to check the offsets.

Thayer


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## mklotz (Oct 12, 2011)

Russell,

Re flywheel calculations: you may want to check out the FLYWHEEL program on my page (url in my sig below).


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## Russel (Oct 12, 2011)

Thanks Marv,

Unfortunately, your program doesn't seem to work with the operating system that I'm using. I'm running Windows 7 Home Premium 64 bit, service pack 1. When I try to run the program I get the dialog you see in the post attachment.

It's funny, I kind of feel like you were reading my mind. I also think that a tapered spokes give flywheels a more elegant appearance. My next step is to figure out the math involved with cutting tapered spokes, so your post was right on the money!

I should be able to figure out everything using the Flywheel Calculations diagram that you included with the flywheel calculator program that you wrote. To calculate the straight spokes I used Google Sketchup to mock up a flywheel diagram and figure the cutting radius for the inner and outer edges of the cut outs. Then, again using Sketchup to measure the needed angles, converted from polar to rectangular coordinated to get the offset and cut distance for the side of the spokes. I made the curved cuts by moving a CNC rotary table with a simple program so that I could make a .020 deep cut (1/8 cutting mill bit) then move to the next spot and make another cut, continuing until I made it all the way through the flywheel. (See second attachment) After completing the inner and outer curved cuts, I used the hand wheels on the mill and moved the flywheel as needed for the spoke offset and cut the sides of the spokes. 

If there is a simpler way, I'm all ears (or eyes and the case may be.)


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## mklotz (Oct 12, 2011)

Use DosBox to run my programs on Windows 7/64. I've tried it on my wife's laptop and it works swimmingly.


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## Russel (Oct 12, 2011)

Thanks again Marv!

DosBox did the trick! After working everything out manually for straight spokes, using your program feels like cheating! I guess we got to save time where we can.

Russ


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## mklotz (Oct 12, 2011)

One of the advantages of enciphering all these computations in the form of a program is the fact that programs have perfect retention over infinite periods of time.

It's not unreasonable in my shop to go several years between the making of two consecutive spoked flywheels. My chances of remembering how to lay out the computations and do the rounding for rational values are vanishingly small. I'd have to rederive everything again. Even if I had committed the derivation to paper, studying it and re-connecting with it would take an hour or two.

The program, OTH, remembers perfectly how to do it and can perform the calculations and produce a results summary ready for printing in a few tenths of a second. And it never makes a math error in the process of doing so.


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## Russel (Oct 26, 2011)

I've gotten a little more done on this project. At this rate, I hate to even estimate how long it will take me to complete it. But, I must say, I'm learning a lot and really enjoying myself.

Anyway, I machined the base and base spacer. Pretty simple work with a mill. Then the cylinder heads. The slight complication with the heads what the round part that fits into the cylinder. While machining the basic part on the mill, I center drilled the center point for the cylinder so that I could locate it with the lathe. The tricky part was clamping such a thin part in the 4 jaw chuck so that I could machine it out to the edge. I used a method from one of Bogstandard's posts, the flywheel one I think, where you use parallels between the part and the chuck face. After locating it in the lathe chuck and clamping it down snugly, I was able to slip the parallels out and machine the round spot without much trouble.

At the bottom of the first photograph you can see one of the cylinder studs. I cheated a little on that part, I used some old 2mm stainless steel bicycle spokes to make it. As it turns out, 2mm is a little undersized for a 2-56 thread, but after threading and trying it, it worked fine.

The screws for the crankcase cover were a bit of a challenge for me. In order to cut the screw driver slot I had to machine about a half inch of quarter inch steel and drill and thread it so that I could use it to hold the screw while I cut the slot with a slitting saw. I did to use the threading tool I made a while back and was very happy to see that it worked well. The screw heads still need a little work on the finish, but the basic screws came out OK. It's funny how I can spend hours making six little screws and get so much enjoyment out of the process. Heck, I could probably buy six 2-56 x .25 screws for a buck or two, but I wanted to make them myself. Oh, I don't have any photos yet, but I also make the two 5-40 screws holding the crankcase to the base.

Next on the list is to finish making the 2-56 nuts and washers for the cylinders.


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## Russel (Oct 31, 2011)

It seems that I'm getting a little faster...it hasn't been a year since the last part and I've machined something else for the radial!

Anyway, I started today with the nut blanks (as I call them) and a little arbor that I made to hold them for machining the flats. 


















The first thing that I needed to do was thread the nut blanks (refer to photos) Then I cut a screw driver slot in the arbor lock nut so that I could tighten it easily. 






Finally, I zeroed the DRO to the circumference of the nut blank, which is parted off from .250 round stock, and decided on a .250 mill bit. So, I moved the mill bit +.125 on the Y axis, to where mill bit is just about touching the nut blank, then moved in .030 for a rough cut, then a .0015 finish cut. I used an index block in the mill vice so after cutting each side I just removed it, turned it one facet, and put it back in the vice to machine the next facet.











It worked out pretty well, I just need to polish the sides of the nuts a little.
















On a side note: I ran out of Protap oil and opened the spare container that I had. I was surprise when the oil came out clear, so I checked the part number and found it to be the same. I was pleased to find that the new formula works better than the old dark Protap that I just used up.


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