Push off fix

[cptdco]

Hello al:
I remember there used to be insturctions on how to properly stone the hammer (I think) to help with a push-off probelm, but I don't think it made it to the new forum. If someone has that (along with the diagram of proper angle) and could post it in response, I would really appriciate it.
Thanks in advance.
Dennis

 

[bountyhunter]

It probably isn't posted because it is not advisable to do it. Push off means somebody hosed the sear on the trigger and stoning it square may fix it for a while, but the surface hardening is gone so it won't last. You don't want to take a stone to the trigger sear faces (or the hammer cocking notches), because the hardened surface is only about .006" deep.

EDIT TO ADD: push off can also happen if the SA cocking notch on the hammer is screwed with or stoned down.

 

[magnum12pm]

I thought the single action cocking notch, being stoned is what usually causes push off, am I mistaken?

It probably isn't posted because it is not advisable to do it. Push off means somebody hosed the DA sear on the hammer and stoning the hammer more may fix it for a while, but the surface hardening is gone so it won't last. You don't want to take a stone to the hammer sear faces, because the hardened surface is only about .006" deep.

 

[HEADKNOCKER]

500 Magnum Nut posted that fix quite a while back..
It requires a 6" long india stone & if I remember right the work was done on the trigger not the hammer..
I used this to fix an L frame but now just can't remember how??
Oh How I miss the old FAQs..
I'll PM 500 Magnum Nut & see if he has the photo & Info..
Gary/Hk

 

[cptdco]

thank you for your replies...I found the 500 magnum fix elsewhere and gave it a try. After light stoning I still had a problem, so I did it a second time. Seems OK now but I didn't lean into it too heavy. And yes, the work is done on the trigger. Bountyhunter may well be right, and if this was a carry or SD piece, I might have taken a different approach, but its a range gun so we'll see how it holds out over time.
Dennis

 

[bountyhunter]

I thought the single action cocking notch, being stoned is what usually causes push off, am I mistaken?

You are correct, stoning the SA cocking notch or the SA sear and changing the angle can cause push off. It can also cut through the hardened layer of metal making the part worthless.

 

[bountyhunter]

thank you for your replies...I found the 500 magnum fix elsewhere and gave it a try. After light stoning I still had a problem, so I did it a second time. Seems OK now but I didn't lean into it too heavy. And yes, the work is done on the trigger. Bountyhunter may well be right, and if this was a carry or SD piece, I might have taken a different approach, but its a range gun so we'll see how it holds out over time.
Dennis

If you find the trigger or hammer sear face is soft and not holding the edge, there was a product we used to use to heat treat sears to surface harden them called Kasenit. Hammers and triggers are expensive, might be worth a try after you get the parts cut right. I have not tried it on SW sears but it works on others for 1911's and HI-powers.

http://www.midwayusa.com/viewProduct/?productNumber=119479

 

[500 Magnum Nut]

Headknocker found me and here are my notes on fixing your problem.
Just go slow, it's easy to do.



To correct push off

The hammer notch must be square, sharp and not rounded. It's only .005 inch tall so use a eye loupe to inspect it. Use a new stone to true it up, if it's not square. (I like ceramic stones for this) Then after the hammer is proper, stoning the trigger will correct the push off.

Remember use a 6 inch long stone. Changing the stone length will affect the trigger pull.

To test the trigger hook, you scrap it on your thumb nail. If nail is scraped off, you got it sharpened correctly.

If you want a lighter single action pull, you dull the angle by lightly stoning the angle parallel to the table top.

 

[bountyhunter]

The Kuhnhausen manual shows the above picture and has these warnings: "The sear face must be completely square and 90 degrees to the body of the trigger. Only a few strokes (of the stone) are required, use extreme caution."

 

[500 Magnum Nut]

This diagram was taken out of my S&W armorer's manual. With follow-up personal info from the AGI school. The nail trick tells you when you have the hook just right.

Remember when you test it, you don't push the hammer spur with all you got, just about half normal trigger pressure. Anybody can create push off on a S&W revolver! The hammer side has a very very fine hook that can strip easily. If the hammer side is damaged, only a new hammer will fix it. The trigger can be salvaged by stoning within reason.

 

[cptdco]

Thanks again. I assume that to keep the angle consistent, you don't actually draw the stone along the hook, but move the stone back and fourth. That's what I did and it seems OK. Can a lighter trigger return spring (or main spring) exacerbate the problem? Or cause push-off where it wasn't before?

 

[Tired Gunsmith]

We found that altered springs in many cases would contribute to push off.
When repairing NYC policemen's revolvers we often found that they had indulged in 'home gunsmithing'.
Many mainsprings reshaped, cut thinner, and of course improperly tightened stock strain screw.
'Stoned' hammers were the first problem, and of course we scrapped any hammer that had any sighn of misuse/abuse.

 

[bountyhunter]

Thanks again. I assume that to keep the angle consistent, you don't actually draw the stone along the hook, but move the stone back and fourth. That's what I did and it seems OK. Can a lighter trigger return spring (or main spring) exacerbate the problem? Or cause push-off where it wasn't before?

I clamp the piece in a Panavise and adjust the part until the correct angle is obtained with the stone horizontal. If you hold the part in your hand, it will rock and round the face cut.