There's nothing new about using something (in addition to your fingers!) to hold a screw when you're grinding it or wire brushing it or whatever. The simplest: a pair of pliers. It grips the screw well in one plane but not in others, so it's hard to smoothly twist the screw. The fanciest? Has to be that of the genius Frank Ford, whose tools are bona fide works of art . . . check this out: http://www.frets.com/HomeShopTech/Tooling/CapScrewHolder/capscrewholder.html
I guess I'm sort of in the middle of the road . . . mine is better than a pair of pliers but nowhere near Frank's level. Mine works for me.
The size of the components doesn't really matter -- scale it up or down, the point is the same. It basically involves two parts -- a threaded inserted part ("plunger") and the internally-threaded external part (I'll call it the grip) which is held by the user. For the plunger, I took a spare carriage bolt. For the grip I used some cold-rolled rod. Chuck up the latter, drill a hole sized appropriate to the carriage bolt. Part the grip off at a point beyond the internal hole you drilled, turn it around, re-chuck it, and drill a central hole that will allow the shaft of the cap-head screw (in this case). To use, drop the latter into the grip, then screw in the plunger. It should hold your cap-head screw tightly enough to do most chores at the grinder.
If you want to pretty it up, lathe off the bottom 3/4 of the threads on the carriage bolt. The remaining threads will do the job and it'll take you 1/4 the time to screw the carriage bolt down. Further enhancements . . . mill some flats on the grip and on the head of the carriage bolt and you can apply some serious torque to really grip that cap-head screw. Knurl the grip for a better, uh, grip if you wish.
Obviously you could use a large screw of about any type as the plunger. If you wish, make several grips with varying sizes of holes for varying sizes of screws to be held. The plunger doesn't have to be a carriage bolt -- use what's nearby. I'd post plans except that as a newcomer I don't want to insult anybody . . . this item is very uncritical, dimension-wise, as well as materials-wise.
The critical part is: save your fingers.
I guess I'm sort of in the middle of the road . . . mine is better than a pair of pliers but nowhere near Frank's level. Mine works for me.
The size of the components doesn't really matter -- scale it up or down, the point is the same. It basically involves two parts -- a threaded inserted part ("plunger") and the internally-threaded external part (I'll call it the grip) which is held by the user. For the plunger, I took a spare carriage bolt. For the grip I used some cold-rolled rod. Chuck up the latter, drill a hole sized appropriate to the carriage bolt. Part the grip off at a point beyond the internal hole you drilled, turn it around, re-chuck it, and drill a central hole that will allow the shaft of the cap-head screw (in this case). To use, drop the latter into the grip, then screw in the plunger. It should hold your cap-head screw tightly enough to do most chores at the grinder.
If you want to pretty it up, lathe off the bottom 3/4 of the threads on the carriage bolt. The remaining threads will do the job and it'll take you 1/4 the time to screw the carriage bolt down. Further enhancements . . . mill some flats on the grip and on the head of the carriage bolt and you can apply some serious torque to really grip that cap-head screw. Knurl the grip for a better, uh, grip if you wish.
Obviously you could use a large screw of about any type as the plunger. If you wish, make several grips with varying sizes of holes for varying sizes of screws to be held. The plunger doesn't have to be a carriage bolt -- use what's nearby. I'd post plans except that as a newcomer I don't want to insult anybody . . . this item is very uncritical, dimension-wise, as well as materials-wise.
The critical part is: save your fingers.
