Engines > Your Own Design
20cc Four Stroke Diesel
Roger B:
Thank you Per :)
I decided to use the Keats angle plate to make the piston. It is set up so I can clamp a stub of 6mm silver steel in a collet and use it to align the Keats on the face plate. The blank was turned to around 0.5mm oversize, the bulk of the conrod space was drilled out and the skirt was bored. The Keats was then moved to the RT on the mill using the same 6mm centring hole and the gudeon pin hole was started from both sides. I have had problems with the drill being deflected by the conrod hole when working from one side. The hole was then opened out to 7.8mm and reamed 8mm.
Roger B:
And one more
Zephyrin:
very nice angle plate you have Roger, very versatile piece of tooling !
although somewhat heavy on the face plate !
"I have had problems with the drill being deflected by the conrod hole when working from one side"
yes, the tip of the drill tip wander on the internal curve of the opposite hole, and both holes are misaligned.
Roger B:
Thank you :) I do like like that angle plate, it helps me to expand the capabilities of (overload ::) )my relatively small machines. With that set up at 500rpm for roughing there was a little rocking at 250 rpm all was stable.
The angle plate was then moved to the milling table to cut the conrod recess. This was done with a 6mm end mill in 1mm steps. The same set up was used to drill the holes for the gudgeon pin fixing grub screws.
Next the angle plate was moved back to the faceplate to finish the piston diameter and cut the ring grooves. There was very little run out, some of which may be due to the relaxation of stresses in the CI blank.
http://www.youtube.com/watch?v=jFr4XJ9ibto
The piston was then turned to the diameter of the plug gauge I used when lapping the cylinder.
Admiral_dk:
I can't say that it surprices me, to see the small amount off wobble in the short video - it is after all taken off the Lathe and put back on again .... it would require some rather expensive gear to be able to do that and have no run-out afterwards ...!
Looks like you're very close to having a new Piston for the Engine :ThumbsUp:
Per
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