Revolver hammer replacement

[socal s&w]

In trying to fix a home-smithing action job, I replaced the hammer on a Model 66, trimmed the lever sear at the bottom for double action and all seemed to fit just fine. However, it does not operate as smoothly as it should.

Is there something else that I need to fit/trim? Did I not trim enough at the bottom of the lever sear? I followed the same angle, but maybe it's off somewhat? I also tried to trim it to the same length as the one that I removed, maybe it's off by a thou or two?

Any help would be appreciated.

Thanks!

 

[john traveler]

After any stoning of hammer & trigger/sear components, you need to reassemble and dry-cycle several hundred times for the sear surfaces to wear in. I do this by hold back the hammer so that it does not actually impact the frame stop surfaces.

After the dry-cycling, relubricate using a molydisulfide grease, and cycle some more. This helps to make for the smoothest, slickest action possible without reducing springs.

The exact length of the DA sear lever determines hammer fall timing. If your DA hammer fall timing is off, you may need to adjust it.

 

[socal s&w]

JT thanks for the insight. I will try some of your suggestions.

It seems that I might not have trimmed enough of the sear lever as I can make the cylinder cycle without the hammer moving, although SA work just fine.

Is there a clearance in measuring that I should know/consider? It appears that all that is needed is clearance for the trigger sear to be able to sit between the lever and the lower hammer sear area. Maybe that's too simple?

 

[john traveler]

Whoah!

The cylinder absolutely should NOT cycle without the hammer lifting and dropping during DA! The only way this can happen if the hammer DA sear spring is kinked, missing, or gummed up in it's cycle, causing the trigger nose to miss engaging it during DA cycle.

The amount of material removed at the bottom of the hamme DA sear is minimal. Remove too much, and the hammer will short stroke, possibly reducing ignition reliability.

I would suggest carefull disassembly and examination to confirm that the DA sear spring is in place and not inadvertently left out.

 

[tomcatt51]

Whoah!
The amount of material removed at the bottom of the hamme DA sear is minimal. Remove too much, and the hammer will short stroke, possibly reducing ignition reliability.

??? The sear (often called the DA sear which it is not) controls getting the hammer started and the "handoff" to the hammer/trigger surfaces that control the last part of hammer travel and hammer fall. The sear length and tip angle/contour affects "handoff". Shorten the sear too much and the hammer/trigger will jam instead of "handoff". Too short will result in a poor "handoff" or a jammed trigger but won't cause it to short stroke.

If the hammer doesn't move back the sear probably isn't staying forward. If the sear spring is missing or damaged this happens. Also happens if you leave the sear out.

Remove the main and rebound springs. Pull the trigger (slowly) and watch how things work. Once the Sear is forward the trigger/sear/hammer engage like gear teeth moving the hammer back. The sear is spring loded to allow it to "get out of the way" and allow the trigger to return (rebound) after hammer fall.

Pull the sideplate back off and see if the sear is forward and why it's not. SA only Model 14's just didn't have the sear.

 

[socal s&w]

Thank you for you thoughts and expertise.

I think what is happening is that the bottom of the lever sear is not trimmed quite enough and it is not allowing the trigger sear enough room to pass it so that it springs back out, thus leaving it in the 'closed' position without allowing the trigger sear to push the hammer up for the hand-off. This would let the cylinder to rotate without the hammer movement, which is similar to how a SA would work.

When I received the new hammer, the lever sear was much longer than the one that was buggered up.

I was wondering if there is a dimension for this area for clearance and angle. Anyone?

 

[tomcatt51]

There are pictures with dimensions in Kuhnhausens manual. I don't have a scanner. Usually the best thing to do is install the old sear in the new hammer.

 

[socal s&w]

Tomcatt51 -

I thought of that, but I am not sure if the pins can be removed easily. I do not have a punch that small. If I can locate one, I will give it a go though!

Thanks for the suggestion!

 

[tomcatt51]

I just use a 1/16" punch with the tip cut short, maybe 5/16" long so it won't "buckle". Sometimes the sear pin is pretty stubborn. The sear basically is clearanced so the sear /hammer doesn't "clamp down" (bind) on the trigger as the angles change while the trigger is pulled. It very closely mimics the way gear teeth are cut so they smoothly engage/disengage and the next pair engage.

 

[socal s&w]

I bought a punch small enough to do the job, man that's one small pin!

Ended up simply switching the sear lever out from the old to the new and the Model 66 now functions great! I could see where the new sear was just a micron away from being exactly like the old sear, a little long, I guess that's all it takes though.

Thanks to all for the suggestions.

 

[trigtechr]

In my shop I kept a supply of half dozen or so triggers and hammers. When installing a new hammer, it is frequently necessary to try another trigger, or vice versa, to get a working fit - even in the world of interchangeable parts there a significant variations on dimensions...
TRIGTECHR