Freelance Inline Twin

[yogi]

Thank you guys for the kind comments! It's very much appreciated. 

Perry, the lap I'm using is an Acrolap. The one I have is about 0.05 mm under size. I don't know how far the lap will expand. I had one expanded about 0.2 mm over nominal. It started to get quite "barrel" shape, only cutting in the middle half of the lap. Not ideal, but it worked. They are brass, and can be turned down to whatever size you need.

Brian, the crank pin is locked between the outer crank disc assemblies, which are then located between the front and rear covers. This secures the whole crank assembly axial in the crankcase. The crank assembly is "self aligning". The disc assemblies are allowed to rotate on the crank pin to find their alignment, and once installed in the case, it can't move any more. I have a section view in the first post, that will help to illustrate. I hope I answered your question.

Thank you for your interest in my project,
Yogi

[Brian Rupnow]

Very clever design, Yogi. I looked at that section view the first time around, and missed that.---Brian

[toolznthings]

Looking good ! 

[yogi]

Hello everyone, it's time for an update. Up next, the pistons:

I started with turning a boss to hold the blank in a collet for the subsequent operations. The piston diameter is 32mm, too large to go directly into a 5C collet.



Chucked in a collet, the OD is turned to finish size and the grooves for the rings are cut:



Using a collet block, it is over to the mill to cut the recess for the connecting rod:







Without removing the piston blank from the collet block, the cross hole is drilled and reamed. This ensures the hole is perfectly perpendicular to the milled recess.





The last operation is to turn off the chucking boss. The piston is clamped very gently in the 3 jaw chuck with some paper to protect the surface from getting marked up.





The finished Pistons:




Thanks for following along, and stay tuned...
Yogi

[zeeprogrammer]

I always dread seeing your posts Yogi. Your parts always look so...so...'finished'. 

[Dave Otto]

Nicely done Yogi!

Dave

[yogi]

Thank you Dave and Zee for the kind comments! It's very much appreciated. 

I have a number of components finished and felt it's time to assemble what I have. I don't want to get too far ahead of myself, making parts. If there is a problem, it would be easier addressed now rather than later. And it's always exiting to see an engine taking shape...

A plug is inserted in the camshaft bore to close it off on the back of the engine.



The crankshaft is finished up on the accessory end with a small diameter shaft extension.



The gear installed on the crankshaft:



The connecting rods are assembled with the pistons and needle roller bearings:



The assembled crankshaft is installed and the crankcase closed.



And the assembled engine block:





To give you an idea of the size of the engine, here with yours truly.




I'm very pleased how the engine has turned out so far. Everything is fitting together and works the way I envisioned it when I designed it. I haven't discovered any design flaws (yet). 

Thank you for following along, and stay tuned for more.
Yogi

[Roger B]

Looks wonderful    What's the machine behind you in the last picture? CNC Deckel?

[stevehuckss396]

I agree, looks wonderful. Thanks for sharing.

[b.lindsey]

Beautiful work Yogi!!  Nice to see your mug too 

Bill

[yogi]

Thank you gentleman for the kind comments! 

Roger, the machine is a Maho MH500 CNC mill.

Bill, I couldn't get the grin off of my face, so my wife made me post it... 

[Dave Otto]

Very nice Yogi!

I really like the ball bearing supported crankshaft.


Dave

[yogi]

Thank you Dave!

I'm very pleased how the crankshaft turned out. It's very low friction. I hope this will materialize in the running characteristic of the engine. I tried to take a short clip of me turning the engine over to demonstrate.
I have already ideas of future engines with this kind of crankshaft.

<a href="https://www.youtube.com/watch?v=ps3SC21VXn0" target="_blank">http://www.youtube.com/watch?v=ps3SC21VXn0</a>

[zeeprogrammer]

  Wow.

I saw the earlier picture of you. Nice to meet you. 

[toolznthings]

I'm up to date on your posts now. Great work as always !!