Bruce Macbeth Engine, European Version

[fumopuc]

Hi Per, my CAD model is created by using the original design of Doug Kelly, as published in the magazine "The Home Shop Machinist Nov/Dec 2012".
So I assume that this a proven design, already build by several model engine makers around the world. Jeff Conner, who has build engine #2, nearly simultaneous with the first model of Doug, has given me the tip, to do this machining very accurate and to avoid any clearance.
He explained me, that if possible, a very slight interference fit will be better. That means always using some fitting blocks in each crank shaft web for assembly/disassembly.
Some other models, seen be him at different shows, seems to develop some clearance at this connection over the time.
Nothing worse for the function, but something may be worth to avoid. I will see what I can archive there.       

[Admiral_dk]

OK - I was just worried when I saw you drawing. Here it looks to me like (slightly) less than half the circumference off each crankhalf is supported -> possible vibrations that might destroy the crank.

a very slight interference fit will be better.

Sounds like a good plan - but will you then have to heat the bearing or cool the two crank halves in order to assemble it ...?... 

Let me assure that I only hope you will be successful - I do have a tendency to look for possible trouble - simply just to avoid it, if possible .... 

[fumopuc]

Let me assure that I only hope you will be successful -

Me too.

[fumopuc]

Some, let´s say positive progress, in my understanding.
I have got it managed to archive a very, very slight press fit with both half's of the crank shafts.
The assembly is only possible by a slight knocking with a soft hammer.
Disassembly is really difficult, but I do have a plan. The outer shafts has got a M 5 Thread.
And the lower shown tool will help me to get it out again.
Only disadvantage, I need something to protect the crank shaft during this operation.
The clamp will be made two times than, one for each side of the LH crank shaft.

[Admiral_dk]

Nice progress and good thinking forward, in order to prevent problems 

[fumopuc]

Next little machining was done.
M 5 thread for possible disassembly.
Machining the groves for they keys. The huge cutter is 2 mm.
Nearly forgotten, the spot face for a possible grub screw of the water pump pulley.
Ultrasonic cleaning for the blacking.
The assembly/disassembly helpers in action.
Finally the adjustment of the axial end play for each crank shaft side.

 

[fumopuc]

... and we do have some motion of the, hopefully, final assembled crank shaft with lower gear train.




[youtube1]https://youtu.be/Cbh0e5fdgoY[/youtube1]








And yes, nearly forgotten "Happy New Year"  to everybody.

[Don1966]

Wow that is awesome Achim love to motion...... 



 
Don

[crueby]

Nice and smooth motion, excellent!

[Roger B]

Looking Good     

[fumopuc]

Don, Chris and Roger, thanks for watching and giving friendly and encouraging comments.

Last weekend I have started some work for the cylinders already, again with the help of my mini CNC mill.This time doing it with steel.
I have been surprised by the result and the way how this little motor with 4.000 rev/min cuts the steel.

[fumopuc]

Last Friday, after seeing some pictures of the real engine in the net again, I was impressed by the service platform, which is always visible there.
All the models I have seen so far, do not have it.
So maybe a reason to attack it.
I have started with the CAD model, unfortunately there are something about 42 components necessary.
For orientation, the diameter of the handrails are 2 mm.

[gbritnell]

Really adds a finishing touch to the engine.
gbritnell

[Dave Otto]

That is going to add some nice detail to the enigne.

Dave

[zeeprogrammer]

Love the handrails. It's made me rethink my design for Spinster (spinning wheel model). Looks like quite a job to do!