Bruce Macbeth Engine, European Version

[fumopuc]

 
Don

Don, thanks. Go to know you are still following along.

[fumopuc]

Looking very nice!
What more do you have to do for a test run??

Sid

Hi Sid, thanks for popping in.


Go question, there is a long list:
Pistons is the next to do, followed by a breaking in for the crank drive on the lathe, may be followed directly by a leakage test of each single cylinder.
Cylinder heads are still without valve seats / valve guides.
Valves
Complete valve train with distributor adapter.
.......


But it will be attacked, see below, nearly everything removed to measure the bores correctly for individual piston making first.

[fumopuc]

Hi everybody,  first from the above mentioned to do list, piston making.
I will try to make each piston matched to the relevant cylinder by 0,05 mm clearance.
For a final check I think it will be good to push the liner at the lathe carefully over each piston.
So the engine is nearly complete disassembled now.
The best of my Chinese measurement tools are at the table, hopefully they will be best used.
My line bore should  be 26 mm, the result of measurement written down.
Also the calculated diameter for each piston.
The blanks are prepared too.

[Roger B]

Looking good    I'm glad to see you are following your normal procedure with a couple of spares   

[fumopuc]

Thanks Roger.
These extra blanks has been used quicker than expected.
On set up part was tested first with all operations to check the whole process.
Turning operations has been successfully.
Also a test fit with the relevant liner.
The grooves for the piston rings worked also quite well.
The pockets for the small con rod eye was a CNC job and also quite well so far.
During the first layer milling I have heard a strange nose and stopped immediately the G-code.
After inspection I could find the cutter loose in the collet.
It was pulled out of the OZ collet in the spindle motor and deeply sticking in the piston.
In this case I could fix everything and restart the CNC job.

[Admiral_dk]

Great progress and I'm sure you are happy that the small incident in the mill didn't cost anything but time 

[fumopuc]

Hi Per, thanks.
But this was not the end of the story.
Next piston has had the same issue at the CNC mill, but this time it was not the set up part anymore,  the cutter dived very deep into the material, that it was a part for the bin.
So it was time to start a research.
What I have found is shown in the picture below, a faulty collet.
There is no contact at the surface, where it should be.
The contact is at the upper end only where the force can not squeeze it together.
So again a new experience.

[fumopuc]

Here a short Video about my piston clearance test of the set up parts.
<a href="https://www.youtube.com/watch?v=_M44gsyXwPM" target="_blank">http://www.youtube.com/watch?v=_M44gsyXwPM</a>


Stay safe everybody.

 

[Roger B]

I have no experience of OZ collets. What machine is this on, not the Proxxon??

[Admiral_dk]

Argh - it's always annoying when you can't trust your tools 

Very nice finish and clearance on your piston 

[fumopuc]

Per, Thanks.

[fumopuc]

I have no experience of OZ collets. What machine is this on, not the Proxxon??

Hi Roger, the original Proxxon spindle motor is with an ER20 collet equipped, but since nearly two years all my CNC milling action is done by a Mafell FM 1000 high speed spindle.
But it seems, that this could be history soon.
I am very happy with this high speed milling with the CNC mill so may be a 1,1 KW Teknomotor spindle with inverter could be the next step.
They are cooled by an electric fan and so they are very quite if in action.
The available torque is also an very interesting thing here and sure an advantage.

[fumopuc]

Hi Everybody,
final machining of all pistons was the next challenge.
The next set up in the collet block for drilling and reaming the gudgeon pin holes and first assembly with a con rod of my set up parts.
Family shot of all pistons and cylinders for the engine.
Followed by the rejected attempts.
One with the already mentioned cutter accident and another one whit two gudgeon pin holes one side.
I have to discuss this with the machine operator within the next pay raise discussion.
Finally my way to clamp a final piston for polishing.

[Don1966]

 




 
Don

[fumopuc]

Thanks Don.


Next job to do, some gudgeon pins, followed by the reassembly of cylinders and crankcase. Hopefully finally.
I have got it manage to buy some black stainless steel M 1,6 bolts for the dummy cover of the clean out door.
So some shortening was necessary only.
Also some black SS bolts for the water inlet pipe are available now, unfortunately hexagon cap head screws are the only way her, due to available  space for a socket.
The aluminium plate on top over all cylinders is used as a jig for adjustment only.