Originally Posted by
LV2TNDM
Now as far as the home-made thread chaser goes.... Looks like a cool project. However, note that the tool you create (and hopefully from a set of steel BB cups, not Al) will not be actual tool steel, so it will dull quickly and not cut very well. Also, his cuts with the ceramic wheel seemed to leave the slot somewhat rounded. If I were cutting, I'd want the edges either vertical, or even undercut a bit so the tool can pull material away instead of just mash. This is how taps are cut in many cases. Oh, and use oil when you're using it, preferably cutting oil.
If you need to
cut threads, the home-made chaser isn't appropriate. You need an actual piloted tap set to do it properly. But the OP is only considering
chasing threads, for which the home made tool can work quite well. You don't need tool steel (although BB cups are hardened steel) or sharp vertical edges on the slots. The chaser only needs to be able to push rust and debris out of the threads and into the slots.