by Doug Coulter » Wed Feb 02, 2011 8:12 pm
I don't think there's dual-spec, you either get the low carbon or the standard amount, which makes that stuff real hard, and more brittle -- the normal stuff work hardens like nothing I've seen before and it's easy to ruin drills with. I think you'd find working pure Ti a joy, actually, it's real ductile, not real-real different than aluminum, just stronger and higher melt point. Just don't get mixed up with 6Al4V -- that stuff is not going to work real well at all. But pure Ti, (like from McMaster in sheet) is now one of my favorite materials, it punches real cleanly, too, and is dirt-simple to spot weld, a little harder to TIG. Copper should be easy, I think that's where the technique originally got started. At least copper you can anneal between work sessions and it's positively stretchy and goopy after that till you work-harden it again. I use strong ammonia to clean it after annealing, works well, but is hard on the eyes and throat -- best done outside and from upwind.
(.50 bmg copper remover is so strong it's silly, but it's great for this)
I would guess that the critical number for a material is elongation before a rupture. For a lot of materials, if you anneal them, you get a fresh start on that one too.
Nice lashup! Do you just push real hard with the tail-stock to keep the piece in there?
Now I know where to get corona balls for my HV stuff -- have a tesla coil that needs one now!
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.