Conversion of 4 Cycle Utility Engine to Steam

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micktoon:
Hi vtsteam , a very interesting project , nice work and nice posting too , thanks for showing .
Cheers Mick

DavidF:
VTsteam, you must be a happy guy right about now. Boring deep holes like that is a tough feat to do well. So what's next? Or are you going to make us wait for the next installment?
:hammer:

vtsteam:
Valve calculations! :hammer: :hammer:

vtsteam:
Thank you Micktoon! :beer:

vtsteam:
BTW, I'm very much liking that spade bit steel. It remained absolutely sharp after 2 hours of boring and light cuts, too, which in a sand casting can be rather dulling. The spade bit was hardened full length, too -- when I tried to file the base end, I couldn't.

Considering the cost of tool steel these days a wide spade bit might come in handy for making other tools. I'll have to think about this.

I also think I'll re-do the brazing and clean this one up to be a little more presentable when I'm done with it on this hole -- it's definitely a keeper boring bar. If I choked up on it (baseball bat expression) and the overhang was say 4" instead of 6" it could probably have taken a .010 cut fairly easily and it can fit in a 3/8" hole -- which is tough to do for a bar of any length.

Another nice thing about using a spade bit here was how easy it was compared to the ones I've made out of drill rod. For those I had to heat to cherry, forge a hook in the end, plunge, re-heat and temper, and then grind to shape.

For the spade bit version, all I had to do was grind it to shape -- the other steps had already been done. Plus a top rake cut was already built into the drill bit. I just ground the end of at slightly less than 90 degrees and very slightly radiused the cutting corner, allowing about 3 degrees of clearance under, and carrying that around the radiused end.

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