Today I was going through some old engines that I had had for many years and found an old KB .35 Greenhead. I decided to clean it up see if I could get it started. When I tried to remove the spray bar it was so corroded that it broke where the spray hole is located. I wondered if I could make one. I checked the threads and they were an odd size .156 od and 40TPI. At any rate I made one and I think it will work OK. The needle valve shuts of 40# of air almost entirely. Very challenging and interesting project.

Keith;

Cutting 40TPI on a .156 dia. is a challenge that most machinists wooldn't want. I know because I am a retired one.

You did very well, you've undoubtly done this before. The finish is excellent. Keep up the good work.

Bill Gruby

I will try to answer everyone in one reply. First off thank all of you for the kind words.

No production is planned. I didn't have to make a needle valve as it was still in good condition

Steps in machining. Fortunately I had a scrap of 1/4 hex brass to start with which saved cuttint the hex. First I turned down the thread portion to .156 then I cut the 40TPI threads. Next I drilled a .063 hole the full length of the finished item. Next turned down the portion up to the hex. Then removed from lathe and drilled the # 58 spray hole, chucked it up in the lathe again and turned down the hose end, leaving the end larger than the main part. Last step was to part off on an angle to form the hose barb.

I bought a lathe about three years ago and I had never done any metal working before that. since then I have added a mill/drill, shaper and horizontal mill to my shop. I first made some accessories for the lathe and then I built a couple of steam engines  from scrap metal. One is a 1/20 th scale model. I am in the process of building another 1/12 th scale engine that is almost completed.

And last, I had no idea that any KB parts would be available, but then I would have missed all the fun of making the part.

A friend do mine recently gave me an old book "Model Making" it was printed in 1927. In the book they have plans for three different model airplane engines. One is a four cylinder designed in a cross pattern. The other two are radial engines one a three cylinder and one six cylinder. They are all steam engines and they use a "flash boiler" the boiler uses gasoline and carries it's own water that is pumped as needed. Here is a picture of one of the engines including the boiler. They run about 3500 RPM so they should be even quieter than an electric