Hi i would like to pick the brains from the experienced. How would you machine this part. I have done a few and must admit it is a pain. You will see from my sketch how i do it from a disc of material twice the size of the actual part, it works, but it is a terrible waste of material. Any...
Here is my Scotty in Elmer's true size. I have a clip of it running but seems to be not of a format recognizable when trying to upload.
Mine has an aluminum piston running in stock standard brass without any rings, just oil grooves as per his drawing and a good sliding fit.
The last two images is video clips of it actually running. I agree there is a fair bit of inbalance, thus causing a bit of vibration. The exhaust vent again through porting on the drive shaft and then out at the back via a drilled port. The reverse lever realy work, i had just to little hands to...
Well was i surprised to have it running the fist time, i thought i might have to fiddle a little with the valve timing. I still need to fit it to a nice wooden base.
Run it about for two minutes and then took the air supply off, was running on a mere breath of air, will measure it sometime.