Stuart 10H build

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Great repair! I especially like how you took the time to replicate the casting draft on the new piece.
Thank you Bronson and rleete. To Bronson, just start on the engine! Your skills will improve along the way and in 99% of the cases of a mistake it can be corrected. I can strongly recommend to start a build over here, you will get all the help you need when you are in need for it. Hope to see your progress here soon!

Made some more progress, not so much but better then nothing.

Made an adapter to hold the sole plate in the lathe


Here it is mounted in the lathe, I am surprised how tight the sole plate is clamped with such a simple adaptor.


Again I hit some hard spots in the castings. The shiny surfaces are the hard parts. Broke a tool on this again :-\




To setup the soleplate straight in the vice I use an electronic angle measurement device that I use to adjust the angle of the rotor blades on the RC heli. Its very simple and quick, zero the device on the top of the vice and gently hit the casting until its zero degrees.


Found the middle of the 17mm bore


and used a really nice feature of the digital readout system, it can calculate a hole pattern. You enter the number of holes, X Y middle point, radius and starting angle


graphical overview of the programmed data


and to position the axis a graphical indication of the target positions


Piece of cake to drill the holes



Finally I can start on the crank! Cutted a piece of round 30mm, faced the ends and milled a flat that will be used as reference to drill the 3 center holes on the side




I had a bad surprise when setting up the lathe to work between the centers. According to the documentation it should have a MK5 taper in the main spindle. When trying to fit, it did not fit! An MK4 is too small, so its something in-between…..and something I do not have. :mad: So another challenge arrived unexpected.


Started to set up the top slide to the correct angle in the spindle nose, which is more or less 2 degrees (does anyone have a clue what kind of taper I will be making?)




Cut of piece of round 40mm and clean up one side and start to turn the taper



I tested a lot to not have the taper too small, with a cam lock the chuck is removed quickly and I let the piece chucked up to not loose centricity.


And to my surprise it worked :eek: Its a very nice fit all around, put it in by hand and I cannot remove it without hitting it from the back



Got lazy during turning and missed my auto feed…… So I use my cordless drill to move the top slide back and forward, it worked very well, did not get tired and the finishing on the part also improved by having a constant feed rate.


Time to make the center tip



And we have a lathe ready for turning between the centers! Since the fit was so good, and the machine is set-up I made another 3 for future use


Hope I have time tomorrow to start turning the crank and that I did not tire you will all these pictures. I will keep you posted about probably how to NOT turn a crank :big:

Have fun, regards Jeroen
Interesting setups and tool-making diversions!

What's the device you're using to find the center of the bore (the one with KT 130 on it)?
Hi Simon,

Its a digital edge finder, it came with the DRO. Its a very nice system, you can choose in the DRO what kind of object you want to measure and then you move the finder agains the workpiece. At the moment the finder detects the workpiece it catches the correct coordinate, so no issue with overshoot. I was lucky to find this thing used on internet, new they are just to expensive for a hobbyist like me.

Hope its clear, if not let me know. Regards Jeroen
Made a start with the crank today and things went not really as planned.

Made the center spots and started turning the crank pin



Crank pin finished


Time to clean up the inner sides. I ground a tool with 8mm width and made 2 cutting sides, one on the left and one on the right. Combine this with a tailstock center too much tightened and you get the result below


Ok, take a deep breath and to reset the mind I made a tool holder for a 6x6mm tool bit that I will use for the next one to clean the inner sides.




Ok, take 2. Made a piece of flat out of 30mm round stock. This will stress the material less during turning (because less material to be cut. Further cut away the not needed material in the mill.




Started with the middle center point to shape the crank sides


Took the part back to the mill and used a saw to make a cut on both sides. After turning the crank pin I just need to saw a little piece and will not stress the crank pin too much.


Crank pin finished and side cleaned up and the part is still in one piece!


Sawed away the material not needed anymore


When I was almost trough I got very warm and sweaty… :eek: :'( … oh no…. I sawed away the wrong side, look at the little cross on the bottom…… :mad:


Ok, time to call it a day. Lets see what I will do tomorrow….. I think I will make it a hybrid solution, or have a third attempt….or both....

Regards Jeroen
Hi Jeroen

I feel for you in making the crankshafts, it took me 3 attempts and I was making them from castings, my brother used to work for st back in the 80's so he got me some extras, its not a mistake its a learning experience.
Once you've finished it I'm sure you will proud of it.

Uh oh! Someone else on these forums did exactly the same thing recently, where they cut off the wrong part of a crankshaft :'(

The recommendation was to scribble on the scrap side with a marker to make it obvious which part to remove.
Really enjoying this build thread, lots of instructional photos, and great explanations, I especially like how you were able to do a work around on that hard spot in the casting base, that was a great technique you did to make a new part on the workpiece.

Keep up the great work, and the photo documentations as well.
Very good work. I'm also in the middle of making one of these engines and the techniques are great to compare.
smfr said:
Uh oh! Someone else on these forums did exactly the same thing recently, where they cut off the wrong part of a crankshaft

I believe it was Brian. Just goes to show that even the most experienced of machinsits sometimes makes a mistake.

I have yet to attempt a one piece, as I'm still screwing up on the multiple piece ones.
You are right Rich, I do not see it as mistakes (ok, cutting off the wrong side was stupid), but as a learning experience. Lesson learned Simon, from now on I will put as many as possible marks on the piece of metal needs to be removed. To Terry and RleeteI I can say that I feel that it is not so difficult, its a matter of patience and keeping focussed on your work.
Thanks Hobby, hows your little vice doing in the shop?

Today I made the hybride solution, did not like to trow away the part.

Cut off the outer ends


and drilled and reamed to 7mm


While the lock tide is drying I made an arbor to hold the crank eccentric to clean up the inner side after removing the round 7 between the webs.


drilled and reamed to 7mm, 4.75mm out of center point


Then milled a 10mm wide slot to support the crank during turning


Locktide dried for about 30 minutes, time to bring the webs to dimension


Added 2 pins of 2.5mm silver steel, just to be sure




Cut away the inner part of 7mm stock with a hand saw (at least I removed the correct pin this time) and cleaned up the inner sides of the web using the arbor made earlier


And of course tested it in the frame.


Do not like the pins visible (due to fact that they are from different materials) and also I discovered that the crankpin should be 7 mm instead of the 5mm I have made (took the wrong dimension, just looked at the side view of the crank on the drawing. There it is mentioned 5mm, did not see however that the middle of the crankpin should be 7). So reasons enough to start attempt number 3! I will prepare 2 blanks, one of free cutting steel (shiny one) and one out of C45 construction steel (the darker one).


Have a very good, healthy and successful 2012, and that you may have plenty of shop time!!

Regards Jeroen
KRV3000, maybe a nice way, but for sure not the intended way!

Made 2 pieces of flat out of the round material and marked CLEARLY what part should be removed and start turing





At the time I needed to reverse the crank, the 7mm was too small for the clamp. I made an intermediate from a piece of scrap aluminum.



Below the result of the parts, take number 3 worked!



I cannot notice any difference between the 2 materials, they both seem to be straight.

Have fun, regards Jeroen
Nice job! I like the "scientific" approach of making the crank from two different materials.

How did you make the flat blanks from the round bar? With a slitting saw?
Very nice Jeroen

So you have 3 cranks now? I reckon the first one would look pretty good with the webs painted black, then you wouldn't see the pins.
Thanks Simon. I have used the mill to make the round pieces flat, see reply #44. Then you consider yourself lucky with a big and stable mill, takes cuts of 5mm with 2 fingers in its nose.... which is good because patience is not my strongest point... ::)

Thats a great idea Steve! Never thought of that option. The build up crank however is useless because I made the crankpin 5mm in diameter instead of the required 7.... :-\ So I have just 2 left out of 4 attempts....

Regards Jeroen
Sorry this post is SO late, but I want to build the engine, and would love to download some of the pictures. I'l like to see pictures of the sole plate and the full engine. But for some reason, I can download what appear to be .JPG files, but I can't open them on my system as .JPGs.

Thanks for any help, and again, sorry for the late posting.

I successfully downloaded a couple, viewing image, and then viewing image again. Others still don't work, but I got the two main ones I wanted.

I saved one as a jpg to my system and I can view it just fine. Not sure what your issue can be. Sorry.