1911 safety issue.

[mainiac]

Did a trigger job on a 1911 today,my 1st attempt ar 1911.came out very nice,crisp and 2lb,10oz pull.all safety checks were tried,and all works well,except....safety on,pull trigger,then switch safety off,and the hammer will drop,right past the halfcock notch.why would this do this,or what have i done?
Btw,,,polished all internals,didnt change any angles,,only real stoning was on the hammer hooks,,took them down to .0018,,,

[country gent]

Most likely there is enough "PLAY" in the mechanism that when you pull the trigger the safety is holding but the hammer moves past the notches allowing it to fall when the safety is released.
Another is the sear leg in the flat spring is weak or out of shape.

[1006]

I think you need a new safety fitted. I do not think you caused the problem. The safety was probably never fit as well as it now needs to be. When you polished up the action parts, I think the safety no longer had a tight enough fit to prevent the sear from traveling far enough to slip off the hammer hooks when the safety is switched off after the trigger is pulled with the safety engaged. The sear probably moved just as much during the test prior to your work, but now it is too much.

[DougGuy]

The sear was probably moving forward before you took down the hooks. Afterwards, the same amount of movement had the nose of the sear partially out from under the hammer hooks because the hooks were shorter. You should probably fit a new safety. I TiG welded and refiled the part on mine that keeps the bottom of the sear from moving.

[tazman]

I am not a gunsmith or 1911 mechanic. I had the same problem with a secondhand 1911 I had purchased a while back.
I took it to a gunsmith who was very good with the 1911 platform. It took him less than 10 minutes to fix the problem and he used the original safety.
I don't know what he did but I never had issues with that again.
I would suggest taking the pistol to a good gunsmith who is familiar with 1911 pistols.

[mainiac]

How can it do it,with the grip safety, not depressed,and how does it miss the half cock notch??

[Plate plinker]

Curious about gun brand?

Might buy a Harrison design fire control group.

[mainiac]

Curious about gun brand?

Might buy a Harrison design fire control group.

A ruger with many thousands ofrounds threw it.i may buy a new safety,or tig that edge up,,and file.

[Petrol & Powder]

I concur with 1006 & DougGuy, the safety was likely poorly fitted to start with and after the amount of engagement was slightly reduced, that flaw became evident.

A 1911 manual safety, when properly fitted, locks the sear AND blocks the hammer when engaged.

It shouldn't be too difficult to correct. Worst case scenario would be to fit a new sear and maybe a safety. Without having the gun in front of me, I cannot diagnose the problem with certainty, but the speculation by 1006 (post #3) seems highly likely to me.

[Plate plinker]

A ruger with many thousands ofrounds threw it.i may buy a new safety,or tig that edge up,,and file.

There ya go! Not familiar with ruger internals. Are the part MIM?

[Petrol & Powder]

How can it do it,with the grip safety, not depressed,and how does it miss the half cock notch??

The grip safety only blocks the trigger bow and the grip safety is not in play for the failure you describe in your first post. Once the sear has moved far enough to release the hammer (which you accomplished when you pulled the trigger with the safety engaged) the only thing holding the hammer is the manual safety. (because the safety likely wasn't properly fitted to start with). As for why the hammer is missing the half cock nock on the way down? There could be several reasons but none of them are relevant because the major failure needs to be corrected first. I suspect the sear spring is too weak to push the sear into the half-cock notch as the hammer falls but you need to correct the primary failure of the manual safety before you move onto the secondary problem of the sear missing the half-cock notch.
In the words of Abraham Lincoln, "One war at a time".

Correct the manual safety issue first and then seek out the other failures.

[mainiac]

The grip safety only blocks the trigger bow and the grip safety is not in play for the failure you describe in your first post. Once the sear has moved far enough to release the hammer (which you accomplished when you pulled the trigger with the safety engaged) the only thing holding the hammer is the manual safety. (because the safety likely wasn't properly fitted to start with). As for why the hammer is missing the half cock nock on the way down? There could be several reasons but none of them are relevant because the major failure needs to be corrected first. I suspect the sear spring is too weak to push the sear into the half-cock notch as the hammer falls but you need to correct the primary failure of the manual safety before you move onto the secondary problem of the sear missing the half-cock notch.
In the words of Abraham Lincoln, "One war at a time".

Correct the manual safety issue first and then seek out the other failures.

Thanks,,makes sence!!

[Mk42gunner]

And this situation illustrated why we do the full safety and function checks any time anything is changed in the fire control mechanism of any fire arm.

I agree with the safety needing to be refitted or replaced to correct the initial problem by the way.

Robert

[KYCaster]

Did a trigger job on a 1911 today,my 1st attempt ar 1911.came out very nice,crisp and 2lb,10oz pull.all safety checks were tried,and all works well,except....safety on,pull trigger,then switch safety off,and the hammer will drop,right past the halfcock notch.why would this do this,or what have i done?
Btw,,,polished all internals,didnt change any angles,,only real stoning was on the hammer hooks,,took them down to .0018,,,

Did you put an extra zero in there or you really under .002 sear engagement? If that is the case it surely explains your problem.

Jerry

[Greg S]

You need to tig up your safety or install and fit a new one, the sear stop block is short and allowing the sear to move to the peak of your new shorter .018 hammer hooks.

To verify, assemble without the grip safety. Pull the hammer back and engage the safety. Look in the safety and see where the nob on the safety blocks the sear. How much does the sear move when you pull the trigger before it gets stopped by the sear block nob on the thumb safety. If the sear moves at all, it is too much. Build up the nob where the sear hits the thumb safety by tig welding and refit until it just goes into position.

If you don't have access to. Tig welder, buy a new one from Brownells.

Did you replace the steel trigger? Is this a Colt or a series 80 style fp block system.? The potential for the pistol to inertia fire with a steel trigger has been increased with the shortened hammer hooks and reduced trigger and sear spring pressure.

Once you get the safety corrected and it passes a function test, live fire with only two rounds in the mag a dozen times to prove it won't go full auto on you. Better to find out proving it than with a mag full.

PM sent.

[1006]

If you google “cylinder and slide safety check”, you will find the instructions for safety checks performed after installing a new action set. These are sent to buyers of the “Cylinder & Slide” action kits for 1911’s.

They include some information regarding hammer hook dimensions and safety engagement.

It is generally believed that hammer and sear modifications on 1911’s with cast/mim parts can result in the uncovering of an interior flaw in the metal, and the removal of the surface hardness. A trigger job on these type parts is likely to fail-sooner or later.

On my Kimbers, I have always ordered either the Cylinder and Slide (C&S) action kits or the EGW kits. I have also installed the C&S kit in a Caspian, a S&W, and a Colt Delta Elite. All total, six guns over the years, both kits seem to safety check and function perfectly without modification. However, a new safety is required about half of the time.

[AndyC]

Btw,,,polished all internals,didnt change any angles

That's scary right there. Polished what, exactly?

Also, I disagree (to an extent - it depends what you've done) that a simple thumb-safety swap alone will fix this - you may have bolloxed up the sear and hammer-engagement too. In that event, the thumb-safety is simply keeping that (possible) faulty engagement from tripping until you release it, but you may indeed need to replace the thumb-safety too, depending what you messed with.

I overlaid 2 pics from Kuhnhausen and animated them to come up with this::




The section between the 2 arrows (the red and blue parts) has to be perfectly fit - a few extra file strokes to the red nub will render the safety useless, because that extra distance you've just created will permit the sear (in blue) to move back if the trigger is pressed - and on a 1911, you'll notice it doesn't take much movement there to release the hammer from the sear-nose (the tiny tip of the sear). Hopefully that's all it is and that a thumb-safety swap might be all you need.

[Petrol & Powder]

AndyC, Thank You for the excellent diagrams and animation. That should help the OP understand the situation.

And I particularly enjoyed your very British use of the term "bolloxed"

[rondog]

That's scary right there. Polished what, exactly?

Also, I disagree (to an extent - it depends what you've done) that a simple thumb-safety swap alone will fix this - you may have bolloxed up the sear and hammer-engagement too. In that event, the thumb-safety is simply keeping that (possible) faulty engagement from tripping until you release it, but you may indeed need to replace the thumb-safety too, depending what you messed with.

I overlaid 2 pics from Kuhnhausen and animated them to come up with this::




The section between the 2 arrows (the red and blue parts) has to be perfectly fit - a few extra file strokes to the red nub will render the safety useless, because that extra distance you've just created will permit the sear (in blue) to move back if the trigger is pressed - and on a 1911, you'll notice it doesn't take much movement there to release the hammer from the sear-nose (the tiny tip of the sear). Hopefully that's all it is and that a thumb-safety swap might be all you need.

When I put WWII Colt parts in my RIA GI model, I had this same issue with the WWII Colt thumb safety. Took it to my gunsmiff, and he TIG'd a tiny nub right at the spot where both arrows are pointing. Just a TINY nub. Hit it a couple licks with a file, all fixed! Blew my mind.

[Baltimoreed]

I’ll also add another thanks for the animation. A picture is worth a thousand words. And 50.00 worth of parts.