David - I have asked Carl at Hobby Horse to make a couple of different special tools for me. When completed, he offered them pre-tempered or post-tempered stating that if they needed any tweaking he couldn't really do that after he had hardened them. The tools that you have used lapping compound on, were they hardened already? And how exactly do you go about lapping the tool? I have spun a couple that would fit into my drill, holding various grits of emery cloth around the shaft, but that was largely ineffective on hardened steel.
And I know what you mean about not getting them apart - I knew better one day as I used a bit that didn't quite fit, and jammed down on it just a bit. Had they not eventually separated, that would have been an ugly process trying to drill that bit out of the rack. I think replacement parts would be the only cure.
George
