The only reason people use Ti for drag blocks is that it produces white sparks ans opposed to orange sparks given off by most steels. Ti is not hard to work at all, it is just different when compared to steels or aluminum. Mild steel will wear down very fast when compared to Ti in this situation. THe proper material for this would be a 500 or 700 series stainles steel. It is very tough, and not that expensive, which seem to be the two driving priorities here. Plus, it will also spark white'ish, not like Ti, but whiter than anything else in the same price range. The downside is this stuff will eat drill bits, so you will need to keep you feed and speed slow and use alot of cutting fluid to cool and lubricate the bit.