CHUKY - The Little Licker

[Alyn Foundry]

Hi Jason and All.

Rather than sully your build thread I will mention that we tried a pseudo " Desmodronic " shutter arrangement on CHUK 2.

An old friend, now departed took some cam castings to a local CNC engineering shop and had them Mill the profile about a 1/4" wide into the casting. Using a small ball race fitted at right angles to the operating rod.

This version was successfully built and run by Martin Lorenzo and was clocked at over 1000 RPM. The picture is on my website, the one with the balancing holes drilled into the flywheel.

I thought that if there were any builders with CNC capability this might be an interesting diversion to the use of a spring return system.

Kind regards, Graham.

[Jasonb]

Thanks for the thought Graham

One thing that did worry me a little about this layout is that the spring could loose it's temper being positioned directly above the flame but so far it seems OK. Infact having played with CHUKY some more once upto temp he runs faster with a smaller flame, could be that it is sucked in easier but may also be due to less heat getting to the outside of the cylinder so the cooling effect on what is inside is better.

I think it could be done without CNC, Unlike Andy I did all the shaping of my cam on the rotary table and a groove could be cut in that way too though an easier option is shown in the pics below. The middle of the cam disc could be milled away to leave say a 1mm thick rim and then an infill cam made that when fixed to the main cam disc would leave a track for the follower to run in.

J