Model 60 hammer block stops trigger reset (shortstroke)

As you may have read, I have replaced my bobbed hammer with a factory-new trigger. The scraping problem has been fixed.

But a result of this project is as follows:

1. Operating the gun is perfect without the hammer block.The trigger snaps forward crisply as before the new hammer project.

2. After installing hammer block, the trigger will not completely reset forward unless I push it with my trigger finger. The hammer block can only be installed one way so probably not pilot error.

3. If I loosen the side plate, the trigger will then snap forward again. How weird, sounds like something binding-up.

4.. I have a new trigger (not installed) which came with the new hammer, however I don't think this would help since it is fine w/o the hammer block installed.

Any suggestions would be appreciated, thanks, Tom

2nd pic shows the limit of trigger reset.

pictures

pictures 2 ea.

What is the prior history of this revolver?

Specifically have you installed a reduced weight Rebound Spring? If so I would suggest installing the original Factory spring and seeing what happens. BTW, on the larger S&W frame sizes I've found that a Rebound spring lighter than 13 lb usually requires a lot of detail work on the rebound slide and frame recess to obtain a good crisp trigger return, so I don't use anything lighter than 13 lbs.

The second area to look at is the DA Sear. Does it come to a sharp point where it contacts the trigger or is there a small chamfer in this area. Look for areas on the DA sear that show that material has been removed by stoning. If you don't see any evidence of the DA Sear having been stoned it means that you have a DA Sear that needs to be "fitted". For that operation I would suggest referring to the S&W Shop Manual by Jerry Kuhnhausen.

hammer block

What you describe is usually caused by the top of the hammer block "flag" catching on the hammer as the hammer block makes it's way upward, and between the face of the hammer and the frame. You can confirm this diagnosis by cycling the action until it malfunctions(trapped), then pull back slightly on the hammer spur. The trigger should then return fully forward. You can use Dykem or "sharpie" to stain the flag enough to confirm contact.

I usually break the top edges of the flag a bit on both sides with a stone or file.....removing enough material to make a small angle on both edges.

The picture is of a new block., and shows the top edge of the flag where the material is to removed.

Having re-read the OP, I believe the part replaced was the original HAMMER, not trigger. I've never seen a "bobbed trigger".

That being the case, besides the good tip on the hammer block, that the double action sear/fly may contribute to the issue. If the DA sear-that spring loaded finger projecting from the front of the hammer below the firing pin-hasn't been properly fitted or has burrs, might be the problem.

You might try installing the fitted sear from your bobbed hammer and see what happens. Watch out for the little spring. Do deburr the sear slot on the hammer.

Changing the trigger return spring is also worth a try. After some wear, you might be able to go back to the reduced power one.

Back in the 80's I was lucky enough to take a couple of gunsmithing classes from Ron Power a man who has written more than a few chapters on Smith & Wesson revolvers ( Ruger also ). Anyway when doing a FULL rework package on K, L & N frames you need to do quite a bit of work on the hammer block and side plate to improve this queer little parts vertical tracking and remove contact rub points and areas where they bind up. The work involves actually bending the base until it hits the walls of the relief channel then stoning back for tight clearance. There are probably five or six places on the hammer block that are tweaked and stoned plus polishing and deburring the side plate. A good action job should include this work not because it necessarily improves speed or trigger feel but more for high speed comp DA work. You don't want anything slowing the trigger return shooting pins plates or any form of speed competition.

I won't go into the steps and procedures needed to clean up this part but it's not uncommon to have it bind up. If the gun is running a 12 pound or lighter reduced power rebound spring then any obstacles along the hammer block path get even worse. If you're going to play with the balance of power by reducing springs then you need to spend the time to reduce friction and unwanted tolerances in the lockwork. Look at the machining marks left on most side plates then at the flimsy nature of the stamped and bent block and you start to get an idea of the possibilities for problems. These blocks were a legal necessity and it sure seems obvious to me that the factory probably did the best they could short of re-designing the entire lockwork. We can't remove them so we have to deal with them

Oh yea Armorer951 has it right on the top or "flag". A couple of bevels with a medium stone will keep this hard angle from hitting the hammer ledge below the nose. If you are really in tune with your gun you can feel the top of the hammer block contact and stumble past this ledge causing a very minor hitch in the trigger return. Unfortunately none of this is visible by removing the side plate.

armorer951 said:

What you describe is usually caused by the top of the hammer block "flag" catching on the hammer as the hammer block makes it's way upward, and between the face of the hammer and the frame. You can confirm the diagnosis by cycling the action until it malfunctions(trapped), then pull back slightly on the hammer spur. The trigger should then return fully forward. You can use Dykem or "sharpie" to stain the flag enough to confirm contact.

I usually break the top edges of the flag a bit on both sides with a stone or file.....removing enough material to make a small angle on both edges.

The picture is of a new block., and shows the top edge of the flag where the material is to removed.

Click to expand...

It's been a number of years since I was building race guns for mostly pin and plate shooters so can I ask you a question since you are in the business. When did they change the design of the hammer blocks ? I never worked on any that had top fingers or " flags" as you call them that had the notch cut out in the middle. Beginning to wonder just how dated am I ? It looks like my experience and advice may not be 100% applicable anymore

Regards

hammer block

The two small "fingers" or nubs on the flag are characteristics of the hammer block from the j-frame series and do not appear on any of the other frame series blocks as far as I know. As far back as I can remember, which would be the early 70's, the j-frame blocks have been designed this way.

You're not dated....and I'm probably right in there with you, age wise. Both your knowledge and experience are very valuable commodities these days.

I have always been grateful to my armorer's school instructors at Smith and Wesson for all the training, both at the factory, and the armorer's field schools over the past 35 years. Especially John Contro, who cheerfully answered every one of my incessant questions. Both the schools and the 20+ years of "in the field" type of experience both repairing, maintaining and building have been invaluable. Feels great having the opportunity to share some of this info with others who need assistance.

Thanks for the info Armorer951 now I do feel a bit stupid. But then I bet I've worked on less than a dozen J frames in my life. Different animal and nothing that I felt I could improve near as much as a K frame. And I'll say this if it hasn't already been said many times before -- this forum is lucky to have your experience to draw on

Regards

I expect I'm not the only person who'd like to see photos showing the Power rework on the hammer block.

I not only read the multipart American Handgunner series on how he did his work, they became part of my revolver manual. Never saw anything about the hammer block.

Sargent Tom said:

As you may have read, I have replaced my bobbed trigger with a factory-new trigger. The scraping problem has been fixed.

But a result of this project is as follows:

1. Operating the gun is perfect without the hammer block.The trigger snaps forward crisply as before the new hammer project.

2. After installing hammer block, the trigger will not completely reset forward unless I push it with my trigger finger. The hammer block can only be installed one way so probably not pilot error.

3. If I loosen the side plate, the trigger will then snap forward again. How weird, sounds like something binding-up.

4.. I have a new trigger (not installed) which came with the new hammer, however I don't think this would help since it is fine w/o the hammer block installed.

Any suggestions would be appreciated, thanks, Tom

2nd pic shows the limit of trigger reset.

Click to expand...

What is a "bobbed" trigger. I've heard of a bobbed hammer. Since you focus on the trigger for your picture, I need some help. What got bobbed?

WR Moore said:

I expect I'm not the only person who'd like to see photos showing the Power rework on the hammer block.

I not only read the multipart American Handgunner series on how he did his work, they became part of my revolver manual. Never saw anything about the hammer block.

Click to expand...

And you will never see any responsible gun rag print information on altering a firearms safety mechanisms. This is why this was never mentioned I'm sure. Go to the S&W Armorer Manual and in big bold print it states Do Not Alter the Hammer Block

This problem of the hammer block flag hanging up can be directly caused by the hammer seat on the top of the rebound slide being too low. This creates a condition where the hammer doesn't cam back as far at it should as soon as it should to make room for the block to cam up between the hammer and the frame.
All kinds of important things going on during hammer/trigger return cycle!

scooter123 said:

What is the prior history of this revolver?

Specifically have you installed a reduced weight Rebound Spring? If so I would suggest installing the original Factory spring and seeing what happens. BTW, on the larger S&W frame sizes I've found that a Rebound spring lighter than 13 lb usually requires a lot of detail work on the rebound slide and frame recess to obtain a good crisp trigger return, so I don't use anything lighter than 13 lbs.

The second area to look at is the DA Sear. Does it come to a sharp point where it contacts the trigger or is there a small chamfer in this area. Look for areas on the DA sear that show that material has been removed by stoning. If you don't see any evidence of the DA Sear having been stoned it means that you have a DA Sear that needs to be "fitted". For that operation I would suggest referring to the S&W Shop Manual by Jerry Kuhnhausen.

Click to expand...

Thank you Scooter. As far as the DA bar being a problem, Chief 38 also talked about it in an email. He decided that this was not the problem since everything is fine w/o the trigger block installed and I guess they are not related to each other.

PS The pistol and all springs are stock, I bought it new, many moons ago.

[.

I usually break the top edges of the flag a bit on both sides with a stone or file.....removing enough material to make a small angle on both edges.

The picture is of a new block., and shows the top edge of the flag where the material is to removed.[/QUOTE]

Thank you Armorer and Gobler. But why would the hammer block be fine with the old (bobbed) hammer?

Note: I have reinstalled the old hammer and it is fine again. I am getting nervous about hang-ups. I will try the ideas everyone has mentioned, please tell me what the hammer block is for.

Pictures

Hearing the advice from Chief 38 and Scooter, here are pics of old and new hammers. Quite a difference in DA sear.

Chief suggests swapping sears, I think I would probably screw it up

You advised the gun works fine with the new hammer IF the hammer block is removed. This would indicate that the hammer block is the problem, not the sear.

You can see in the most recent photo that the bobbed hammer is either an earlier version with a squared cut under the nose, or someone has modified the bobbed hammer by removing material from the area of the "ledge" just below the bottom of the hammer nose. This area is where the top of the hammer block is making contact on the new hammer. The hammer does not (should not be) have to be modified to accomodate the block. The contact can be eliminated by filing an angle on the hammer block at the top edge of each side of the flag.

The contact can also be caused by the hammer seat on the rebound slide being too low....as I indicated in my previous post #13. This can be solved by fitting a new rebound slide.
The reason the gun functions correctly with the bobbed hammer is the hammer appears to have been modified to accomodate the block.

To answer your question about the function of the hammer block......The hammer block is a secondary safety feature, with the primary safety being the hammer seat on the rebound slide, and the rebound seat on the hammer. These design features insure that the gun will fire....the hammer nose will (can) reach the primer.... only when the trigger is held back.

I am enjoying this thread a lot since its been a while since I got my head back into these fine revolvers. Armorer951 most likely has this all pretty much diagnosed but let me add a few more considerations. Keep in mind gunsmithing by forum is not the smartest way to fix a gun but better than nothing.

Anyway as armorer951 says the rebound slide hammer seat is one of several critical controlling surfaces for the whole hammer stop/safety action. However the reason your gun works with the altered bobbed hammer and not the stock issue MAY be as simple as this.

Bobbed hammers are only used in the DA mode and because they are lighter and the drop in DA is shorter you get lighter hits. The hammer hits harder in SA than DA simply because the drop or distance is greater. The gunsmith has to adjust for this by reducing the hammer face a bit to increase firing pin or nose protrusion. When you alter the hammer face you are also altering the geometry where the hammer meets the hammer seat on the rebound slide. So if you reduce material at the hammer face you must also adjust the hammer seat. As is the case almost everywhere in these guns nothing is free.

With the above in mind it is possible that the alterations made to fit up and get reliable ignition with a lighter bobbed hammer are the nut of your problem. The hammer is the elephant in the room. It is the heaviest piece in the lockwork and needs plenty of mainspring and rebound slide power to cycle. Lighten the hammer increase the hammer nose protrusion and you can usually get by with less of everything if done right. If done right.

The hammer seat the armorer951 talks about has an abrupt hard angle face that the hammer foot has to transition and jump over to rest on the hammer seat. This can be lightly stoned to ease that edge but like the hammer stop these are safety features and won't tolerate inexperienced tools and hands. Rebound slides are cheap, hammers aren't. Just some food for thought.

Make sure the new hammer block fits and works very smoothly in the groove where it fits in the side plate. It must be straight in all respects and may need a slight bit of stoning along the edges where it can contact the groove in the sideplate. Lay the hammer block on a perfectly straight edge and examine it very closely. If it is not straight on any side, a light tap with a small hammer should straighten it. Make sure all edges are slightly broken and that each flat portion is square with the piece. You might also have an issue with the groove in the sideplate that requires a magnifying glass to detect. It doesn't take much binding to have a negative affect. Good luck!

kthom said:

Make sure the new hammer block fits and works very smoothly in the groove where it fits in the side plate. It must be straight in all respects and may need a slight bit of stoning along the edges where it can contact the groove in the sideplate. Lay the hammer block on a perfectly straight edge and examine it very closely. If it is not straight on any side, a light tap with a small hammer should straighten it. Make sure all edges are slightly broken and that each flat portion is square with the piece. You might also have an issue with the groove in the sideplate that requires a magnifying glass to detect. It doesn't take much binding to have a negative affect. Good luck!

Click to expand...

Thanks Pudge, but I don't have a new hammer block. It is original with the gun, bought when new.