So, this certainly isn't anything that people couldn't figure out for themselves, but since I took the time to do it, I figured that I'd post up about the tooling/process to convert "standard" (5/16-24 threaded) bolt knobs to be compatible with the ARC bolt knob attachment method.
NOTE - ensure that the bolt knob has the length necessary to support a "cavity" that's .900" deep, PLUS another ~.250" or so for the 10-32 screw that secures the bolt knob to the ARC bolt handle
In any event, here's the tooling that I gathered to complete bolt knob conversions:
In any event, my process is to wrap the bolt knob in some protective tape and get it chucked in the lathe, ensure that there is a .450-ish face on the mating/open end of the knob, use the bolt/guide to drill the #24 hole .250" deep in the "base" of the "cavity", use the bolt/guide to ream the same hole to #21 (.159") size, use the 10mm end mill to sink a .060-ish counter bore in the mating/open face of the knob, then just run the 8mm reamer in until it bottoms out in the hole/cavity. Clean everything out with brake clean/air, insert the drop-in tap guide (which has a .399 shoulder to locate on the counterbore), and use first the plug, then the bottoming tap to cut the threads for the bolt retention screw. One more clean out with brake clean/air, some Loctite on the first few threads of the 10-32 set screw, and in she goes with a 3/32 hex key... nicely snugged and left alone for awhile to let the Loctite set.
The 7.9mm drill bit comes in to play if the "cavity" of the knob isn't deep enough to support the .89x length of the ARC bolt handle from the "flange" to the tip.
FWIW, I figure all of these ops could also be done on a mill/drill press if that's what you have available to you (with the possible challenge of cutting the .450-ish face on the knob if it's not already present; although if you have a flycutter, that'd do the trick there).
Anyhoo, there ya go... good luck, God bless, your mileage may vary, batteries not included, etc...
NOTE - ensure that the bolt knob has the length necessary to support a "cavity" that's .900" deep, PLUS another ~.250" or so for the 10-32 screw that secures the bolt knob to the ARC bolt handle
In any event, here's the tooling that I gathered to complete bolt knob conversions:
- #24 split point drill bit(s)
- #21 reamer
- 10-32 plug and bottoming taps
- 8mm reamer
- 10mm end mill
- 7.9mm split point drill bit (optional)
- 10-32 x 7/16" cup point set screw(s)
In any event, my process is to wrap the bolt knob in some protective tape and get it chucked in the lathe, ensure that there is a .450-ish face on the mating/open end of the knob, use the bolt/guide to drill the #24 hole .250" deep in the "base" of the "cavity", use the bolt/guide to ream the same hole to #21 (.159") size, use the 10mm end mill to sink a .060-ish counter bore in the mating/open face of the knob, then just run the 8mm reamer in until it bottoms out in the hole/cavity. Clean everything out with brake clean/air, insert the drop-in tap guide (which has a .399 shoulder to locate on the counterbore), and use first the plug, then the bottoming tap to cut the threads for the bolt retention screw. One more clean out with brake clean/air, some Loctite on the first few threads of the 10-32 set screw, and in she goes with a 3/32 hex key... nicely snugged and left alone for awhile to let the Loctite set.
The 7.9mm drill bit comes in to play if the "cavity" of the knob isn't deep enough to support the .89x length of the ARC bolt handle from the "flange" to the tip.
FWIW, I figure all of these ops could also be done on a mill/drill press if that's what you have available to you (with the possible challenge of cutting the .450-ish face on the knob if it's not already present; although if you have a flycutter, that'd do the trick there).
Anyhoo, there ya go... good luck, God bless, your mileage may vary, batteries not included, etc...
