1911 Thumb safety question


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FullEffect1911
April 29, 2008, 09:35 AM
Normally I wouldn't ask about a part that I think is fine, however since this is a safety issue, I would rather make absolute certain everything is fine.

I fitted a new thumb safety in my 1911. After filing for a while i literally used one final swipe of a file and the safety fit behind the sear. The safety fits in behind the sear snugly, and I can see no discernible movement. After fully assembling the gun, the hammer doesn't drop with the safety on, or drop when the safety goes off, and there is no click when the hammer is pulled back slightly (gun passes the C&S click test).

The only issue I have is that when the safety is engaged the hammer seems to go back just a little. Presumably this is because of such a tight fit between the thumb safety and the sear that I am actually pushing the hammer back just a bit. I did not notice this at first, and i have to hold the gun steady on the table to see it. The hammer does not move at all when the safety is on and the trigger is pulled.

Does this sound fine or will i have to take a bit more off the safety to get zero hammer movement?

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GLOCK45GUY
April 29, 2008, 10:31 AM
It sounds like you have some contact between the TS and the "half moon" cutout in the hammer itself.

I can't say for certain that it's OK from a safety stand point, but I'd fix it just because it bugs the hell out of me that things don't fit together like they would from the factory.

I fit this portion of the hammer to the TS, and not the other way around.

Color the cut out in the hammer with a blue felt tip chisel point marker, fit the two parts together, move them around, disassemble and see where the interference is. Remove a little material from the hammer with a wooden dowel ( or some other round object that fits good) wrapped in light (no more than 320 grit) sand paper and go super slow. You may even get away with only polishing this area.

Maybe I'm wrong and some other real gunsmith will chime in, but this is off the top of my head. Hope all goes well.

1911Tuner
April 29, 2008, 11:34 AM
The point on the safety lug still needs to be reduced a little. It's pressing on the sear's rectangular pad and forcing the hammer past full cock. If you thumb the hammer back a little before engaging the safety, you'll find that it moves into the on-safe position a little easier and more crisply...and probably a little higher, too.

By watching the function with the pistol assembled without the grip safety, you can see exactly where and how much more needs to be taken. Remember that the safety moves in an arc...so the area of removal will change slightly.

FullEffect1911
April 29, 2008, 11:54 AM
boy, sometimes i'm glad i worry about everything. I'll correct the problem tonight and post back here.

I'm gonna go ahead and assume that very little material needs to be removed right?

1911Tuner
April 29, 2008, 12:05 PM
I'm gonna go ahead and assume that very little material needs to be removed right?

Yep. It's down to a "Take a light cut and try it" exercise. You want it to just bear against the pad without actually putting pressure on it.

FullEffect1911
April 29, 2008, 03:27 PM
okay, I think that should about do it. There is about as much contact as the original springfield thumb safety had. There is no sear movement when the thumb safety is on with the trigger pulled.

There is .001" of movement from the hammer when the thumb safety is being engaged and disengaged. There is no movement from the hammer with the safety engaged and trigger pulled. So sayith my dial indicator.

Is this .001" of movement fine as far as pressure on the sear is concerned?

1911Tuner
April 29, 2008, 04:25 PM
Is this .001" of movement fine as far as pressure on the sear is concerned?

It'll wear in and seat itself pretty quickly. Well done, lad! Well done!

FullEffect1911
April 29, 2008, 04:54 PM
thank you Tuner, I very much appreciate the help.

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