Looking for a bit, .022 x .186

[Retired W4]

The strain screw on my American Arms Co. (Boston) top break revolver has a very narrow slot, .022 in fact. I checked with Chapman's and they hit on either side of me but did not have the exact size. Do not recall the length of theirs. The screw is mounted low on the hammer spring and it takes some torque to to screw it down, so I need the full width blade (.186) to fill the slot. Ace was no help and I doubt Home Depot would have what I need.

Any idea of a source for this hollow ground bit that I need?

 

[Protocall_Design]

It might be easier to make the slot wider (.035 to .040) than to find a driver that narrow. The .022 thickness is more likely to shear off than an .032 one. A 3/16 x 1/32 is a standard size in a 1/4" hex bit.

 

[ColbyBruce]

Did you try Fastenal?

 

[Retired W4]

No help from Fastanal. Making the slot wider is easier said than done. The steel the screw is made of is really hard stuff. Couldn't bugger it with the bits I tried earlier. I'm using sand paper in the slot but it's slow going. Don't have a file skinny enough to go in the slot.

 

[Protocall_Design]

You could try an abrasive or diamond cutoff wheel in the Dremel, or send it to me and I'll machine it.

 

[Retired W4]

You could try an abrasive or diamond cutoff wheel in the Dremel, or send it to me and I'll machine it.

Let me try the dremel cut off wheel. With my tremors and neuropathy operations like that are difficult, so I might be taking you up on that offer.

 

[Retired W4]

Cut off is too thick. My hair just grew out after chemo and now I want to pull it out.

 

[ColbyBruce]

If you know anyone who owns O/U shotguns they may have a set of fine blade screwdrivers as most of the European offerings used screws with fine slits.

 

[2152hq]

File a screwdriver blade to fit the screw.
It's the common practice,,or at least was before all the screwdriver sets w/the detachable bits became the thing to have.

A good quality screwdriver blade should have the same hardness as a properly tempered V spring.
You can cut it with a clean, sharp file, but just barely.
Don't make the blade portion much longer than needed to enter the slot and clear the top of the screw before tapering off and into the shank of the tool.
Those long, pretty and thin blades will twist when under heavy torque and just like a spring,,they can only flex just so far and then they will crack (or bend if poor quality).

Lots of Euro guns have slots down into the .020 width and even thinner.

 

[stang1911]

Brownell's 180-1 bit .022 x .176 ?

 

[Retired W4]

All right. I cranked up my RIKON belt/disk sander and went to work on an old Craftsman screw driver and got it to fit the slot.

I want to thank all ya'll for the inspiration to keep going on this project.

BTW, the little switch on the side plate is not for a 1 stage/2 stage trigger. It is a single action device (note the claw and notch at the bottom of the hammer, which is cocked by pulling the trigger. It stays there until you pull the trigger again. With the switch in the aft position it's standard DA.

 

[ColbyBruce]

I am glad you made some progress on that piece.

 

[Protocall_Design]

Congrats on the screwdriver! Do all of those have 2 sets of cylinder notches?

 

[Retired W4]

Congrats on the screwdriver! Do all of those have 2 sets of cylinder notches?

As far as I know that is a standard feature of the model. The trigger pull got much better after I cleaned it. Still too heavy, but smooth.

 

[Kp321]

Nothing better than the Brownells Magna-tip bits.