drive repair tips?

der> I've seen those, though not (so far) in disk drives. der> I have an interchangeable-bit screwdriver whose set of bits der> includes some three dozen "security" bits of various kinds. I der> don't know the names of most of them, but there are der> pin-in-the-middle torx, pin-in-the-middle hexagon ("Allen"), der> something I might call a three-bladed Phillips (like a Phillips der> but with one vane removed and the remaining three vanes at 120?? der> from one another), ... I've seen those used on airliner wings -- 737 perhaps. Don't know the name. der> and what I might call der> "butterfly" bits - I have no simple unambiguous name for the der> shape, but for those who know PostScript or who have a der> PostScript interpreter, "250 500 translate 0 -15 moveto 0 0 50 der> -40 40 arc 0 15 lineto 0 0 50 140 220 arc closepath stroke" der> gives a fair idea of it. Nice description. I think those are "Clutch" bits. der> Plus a bunch of non-"security" bits: regular hexagon (both inch der> and metric), square ("Robertson"), Phillips, ordinary flat, and der> something which I didn't recognize when I got it but thanks to der> an earlier discussion here I now know is called Pozidriv :) - der> all in various sizes. der> No, finding the screwdrivers is unlikely to be my problem. :) Sounds like all you're missing is Bristol Spline. Those seem to be rather old; the only place I ran into them is in a 1950s vintage Collins radio (51J-3). The Xcelite "99" roll pack toolkit has those, and you can get them separately too. A Bristol bit looks like a cylinder with 4 (small sizes) or 6 (larger sizes) square-bottom fairly narrow grooves cut into them. So it's very different from Torx (almost all groove, and round-bottomed) or Allen (hexagon); if you need to undo a Bristol spline screw, you'll need the real tool. paul