Making a water-cooling coil for a Cox .049 engine

I cut a 10 inch length piece of 1/8" OD soft-copper tubing.. and wound it around a 1/2" twist-drill's "shank".. (which is 1/2" diameter...) I used the drill in my drill-press to drill a hole in a block of wood.. for the same twist-drill to fit in.. to serve as the "winding-post".





It was not a difficult or high-effort job. No hint of creasing anywhere on the tube.





I used some 3/8" drive socket-wrenches with a short extension.. to gradually increase the inner-diameter of the coil.. until until it's just slightly smaller than the outer-diameter of the cylinder/head. The soft copper is easy to work.. once you get a feel for it... (recoil/springy-ness/memory). Once it's close to the right diameter; squeezing both ends backward; spreads the coil open.. allowing the coil to be pushed onto/over the glow-head. When released; the coil "recoils".. and the cooling-fins on the cylinder/head "key-into" the coil-separations to help hold the coil in place. I was pleased with the way it worked out. This is all new to me... and there's been lots of hiccups along the way. It's always a good feeling when something comes together as expected.