66-7 "hitch" with hammer block, but works fine without it...

[bglaze]

Heya, folks! I am a new poster, though I have been a lurker for a long time.

I bought a very nice used 66-7 w/4" barrel yesterday. I spent a fair amount of time both in the store and once I got it home dry-firing it with snap caps and inspecting it. It functions and looks awesome, and I believe I got a fair deal ($499 plus tax)...

Since it's a used gun, I decided to detail strip it and clean it inside and out so as to be sure of its reliability for carry. I also polished it up with Mother's Mag Polish and Mother's Billet Polish to give it a little eye appeal. I've done this to all my stainless S&W's, and it's kind of becoming a tradition.

So, I detail stripped it, cleaned all the parts, polished the visible exterior of the gun (FYI: I never polish the mechanical surface of any part), and then I reassembled it.

Upon reassembling I noticed something immediately. The first time I reassembled it I could not cock the hammer all the way back. When the hammer reached the 90% point in its backwards travel it hit a "hitch" and stopped. So, I disassembled and investigated the parts. Again, I found nothing out of place, so I reassembled and got the same results.

I have now disassembled and reassembled numerous times, sometimes I have disassembled it FULLY, leaving no parts in the gun. But upon reassembly there is always a hitch when the hammer nears its cocking point. The first few times I reassembled it, the hitch was keeping the hammer from cocking at all. Now the hitch is less obtrusive; the hammer cocks, but I have to give it slightly more force to get past the hitch than I should.

I will note that the gun functions PERFECTLY if the hammer block is left out.

I thought the hammer block might be bent or something, so I replaced it with another (I happened to have an identical one laying around from another similar model S&W). But I get the same result with either. There is no visible damage to the hammer block.

I have closely inspected every part in the gun, and I've yet to find any visible damage or misalignment.

Someone else had suggested that the trigger post or one of the other posts may be bent. But they all seem perfectly perpendicular to the frame upon which they are mounted.

I have also flip-flopped all the springs at one point or another, just case I had them in the "wrong" way. But I get the same result nevertheless.

I am hoping someone else has come upon this problem and has a suggestion. I have taken numerous pictures if the internal parts for your inspection. Please take a look at them and let me know what you think!

Thanks so much, and here are the pictures:

First Set of Pictures

Second Set of Pictures

Third Set of Pictures

Fourth Set of Pictures

Fifth Set of Pictures

 

[haifabuddy]

Happened to me once. I think the strain screw and mainspring were loose or out of alignment.

 

[Alk8944]

Don't know that the hammer block has anything to do with it. As haifabuddy mentions there is a good chance the mainspring is the problem and is stubbing into the hammer. The mainspring looks entirely too straight, there should be more arch to it. Make sure the strain screw is tight and see if it goes away.

Both the symptom you describe and the appearance of the mainspring point to this.

The strain screw is not an adjustment! It is supposed to be tight at all times. A loose strain screw is the most common cause of malfunctions of all types in a Smith revolver.

 

[shawn mccarver]

Interesting that it worked fine before you took it apart. My guess is that something was not reassembled correctly.

 

[Big Cholla]

It appears to me from the 'rub' mark the hammer block is leaving in the sideplate channel that the hammer is forcing the hammer block over against the sideplate. That will cramp up the hammer block and give you your problem. As I see the possible solution is to reduce the width of the hammer at the point where it pivots around its frame stud. Also polish the heck out of that sideplate channel as well as both sides of the hammer block strut arm. It wouldn't hurt to also polish the toe of the hammer block as it looked like it was rubbing the other side of the frame as well. When polishing sideplate hammer block channels, I use a Foredom tool with appropriate grit rubber wheels. You might find a Dremmel Tool and use that. You can use the same wheel to polish both sides of the hammer block and its toe. .... Big Cholla ............ My complements on your photography.

 

[500 Magnum Nut]

Put all the side screws in tight. If the cover is loose the rebound block could twist.
Strain screw in tight (possibly it, as it looks backed out).
Open the cylinder, pull thumb release to the rear and cock the gun. Is it better? This will isolate what part of the gun to look further at. if it's not the main spring....

You are a brave man to reinstall the hand spring in the trigger. Most can't do it!
Oh & Nice polish job!

 

[bglaze]

A HUGE THANK YOU to everyone who suggested to check the main spring. I thought I had it screwed in as tightly as it would go, but after messing with the angle the mainspring was sitting at and screwing it back in tightly the problem had now completely disappeared.

It has been over 24 hours of messing with this gun, and I will say I've learned a lot more than I knew before.

I am mad and glad that the same time that it ended up being that simple.

You all are geniuses, and my truest thanks to you for chiming in and helping me with this! I almost drove 2 hours each way tomorrow to take it to a gunsmith to get a hands on opinion. It's so much nicer to just fix it right here at home and save the gas and money.

 

[bodger]

I'm reviving this thread because I just had the same problem with my Model 66.
I was taking the lock out, I had previously removed only the "flag", but not the remaining parts. I plan on ordering one of BullesEye Smith's now famous plugs.

I had the same "hitch" upon re-assembly. I found this thread and re-positioned the main spring several times to insure it was lined up.

The action would function perfectly without the hammer block installed, even with the sideplate back on and the screws tightened.
Of course, in the process of all of this I had to re-install the hand spring twice, a chore I could live without.

I finally took a Dremel and lightly polished the surfaces of the hammer block, especially at the bottom where it travels around in the side plate channel.
That solved the problem. I have had this gun apart many times and never had this problem. The only thing I can think of is that maybe the rebound slide was some how moving just a hair more than it ever did and this was cramming the hammer block against the sideplate channel.

I was up until 3 AM messing with this thing. Now I'm wondering if maybe I didn't seat the hand spring into the blind hole and possibly the trigger lever isn't seated properly and causing a little extra throw on the rebound slide.

Also, does anyone know if the rebound slide is reversible, meaning is there any difference in which end you put in first?

ETA: Indeed, it was the hand spring. It was not seated correctly and was causing the rebound slide to push the hammer block too far to the rear.
Oh well, an extra drill on hand spring placement and now I have a shiny trigger block.

 

[Alk8944]

bodger,

Just a comment about Dremel tools and guns. A Dremel should never be used in the lockwork of a revolver, there is no place for this and a lot of damage can be done.

Shininess is not the goal when polishing lock parts, smoothness is. This is not achieved by use of either a polishing bob and compound or Cratex wheels.

What is desired is smoothness and evenness. The proper way to achieve this is with a Hard Arkansas stone. The stone is oiled and the part to be polished laid on the stone and rubbed lightly, lenghtwise of part travel, on the stone until any rough areas/burrs are removed and then stop. At first you will feel dragging, when this goes away and it feels like the part is floating on the oil film, stop, you are done. Please note that you will not see any difference in the appearance of the part, just feel on the stone. On the rebound slide do this to both sides and the bottom. The rear (toward frame) bottom corner of the rebound slide can be slightly beveled to good effect also. The bevel needs only to be large enough to see and can be done with a fine single-cut file and should be done before the stoning. This will give better results than the Dremel tool ever could.

 

[bodger]

bodger,

Just a comment about Dremel tools and guns. A Dremel should never be used in the lockwork of a revolver, there is no place for this and a lot of damage can be done.

Shininess is not the goal when polishing lock parts, smoothness is. This is not achieved by use of either a polishing bob and compound or Cratex wheels.

What is desired is smoothness and evenness. The proper way to achieve this is with a Hard Arkansas stone. The stone is oiled and the part to be polished laid on the stone and rubbed lightly, lenghtwise of part travel, on the stone until any rough areas/burrs are removed and then stop. At first you will feel dragging, when this goes away and it feels like the part is floating on the oil film, stop, you are done. Please note that you will not see any difference in the appearance of the part, just feel on the stone. On the rebound slide do this to both sides and the bottom. The rear (toward frame) bottom corner of the rebound slide can be slightly beveled to good effect also. The bevel needs only to be large enough to see and can be done with a fine single-cut file and should be done before the stoning. This will give better results than the Dremel tool ever could.

Good to know, thanks.
I had the trigger block out of the lockwork when I buffed it. I can see what you mean, no way to control a Dremel in there and could wreak havoc with other parts.
It's that dang hand spring that is so hard to re-assemble. I've done it several times, but apparently didn't get it exactly right and it caused problems this time.
If it weren't for that ridiculous lock, I doubt I would touch the works.