Slotted screw guide

[mklotz]

If you ever have occasion to use a 6" x 1/8" screwdriver on slotted screws...





you'll appreciate this device to keep the screwdriver from slipping out of the screw slot. (There's a special circle in Hell for the idiots who devised slotted screws.)

It's a very simple lathe job. Slim down the tip of some 1/4" brass, drill through to accommodate the screwdriver shaft and enlarge the business end to fit over the screw head. Cross drill and tap 2-56 for a tiny set screw. (These screws require a 0.035" hex wrench. My handled one is shown in the photo.)





Here it's assembled on the driver.





In use it's extended down over the point to seat around the screw head. Rotate driver until you feel it drop into the slot. Tighten set screw and you're good to go. When not needed, store it on the screwdriver shaft up by the handle.

Although intended for miniature work, the idea is easily extended to larger drivers.

[Toolmaker51]

The "special circle in hell" is because they didn't create hollow ground (parallel) bits to drive them with, and originally the slots were filed and or sawn (lacking mill cutters), which nothing worked short of hand-fitting. No question they were filed into an approximation of thickness but tapered, so it only bore on a slots edges.
A good case of which came first, chicken or egg.

Making very good parallel drivers is simple enough math; of bit size desired with rod size and cutter diameter for the offsets. Cut conventional, not climb, with smallest 4-flute endmill long enough for rod diameter. It's easier to index than compensate axis backlash, by repeating same conventional motion.
Do three passes; roughing, finishing after measuring, spring cut.
If it was good enough at the Weatherby South Gate Gun Shop in an Auto-5 Browning with crazy narrow but wide screw heads, well, it's good enough!
Use oil or water hardening drill rod, they'll last you forever once heat treated and drawn back. If it should break, cut off an inch and re-do.

[mklotz]

It's more than having a properly ground set of drivers. I have a good set of gunsmith drivers but, regardless, I'd gladly hammer the nails into the crucifix bearing the inventor of slotted screws. Square or hex drive self-center the driver and eliminate cam out plus can be made to hold the fastener on the driver when working where fingers can't reach.

Don't ask me about Phillips head. If I had the inventor on the boards, I'd use fine pitch sheet metal screws in place of the nails.

[Toolmaker51]

<<<<snip>>>>
Don't ask me about Phillips head. If I had the inventor on the boards, I'd use fine pitch sheet metal screws in place of the nails.

Agreed there, bet that's not his real name either... the certain king of worst drive methods.
Or he went underground, equivalent to witness-protection program.