Hammer rubbing on frame/shims?

[prairieviper]

I have a model 66 where the hammer is rubbing on the right side. I have read a bit about shims and it seems to be the simple solution. My question is, why couldn't I just go to a hardware store and find an appropriate size washer to use as a shim. Granted, I know nothing about gunsmithing revolvers or shims but looking at shim kits, it appears that the shims are nothing more than washers. Wouldn't it be cheaper to just buy these from the local hardware store?

Any advice would be appreciated.

 

[garbler]

As I recall Ron Power supplies these shims to Brownells and they are .002" or .003" thick, have a specific ID to fit the stud and OD. So if you've never seen one but think you can get one at your local hardware store -- go for it.

Good luck

 

[gmborkovic]

Washers are to thick. Shims can vary in thickness by as little as 0.001".
I dont have any, I sold them all. If I still had some I would send you some.

 

[prairieviper]

Thanks for the replies and education.

 

[gwpercle]

I thought I could walk into any hardware store and buy a screw to fit my revolver grips.......That didn't work out at all. I even went to a store that sells nothing but screws and fasteners to industries ...No luck there either.
Good luck on the hardware store washer, my quest for a screw ate up a whole Saturday ( I went to every place in town that sold screws) and a Monday morning trip to the Industrial Fastener Specialist and got me zilch.
I would just order the shims from a gun place....save a lot of wasted time!
Gary

 

[markeb]

It's not uncommon to have a bit of hammer rub, some do and some don't. If you can, post a pic of the rub mark. If it is minimal, I would just let it be.

 

[ontargetagain]

These folks are tops for customer service, I have purchased from them a few times and all was perfect!
TriggerShims Brand Shim Kits

Don't hold me to it but I think you need about 3-4 thousands of freeplay so the hammer does not bind. Anything over that you divide by '2' and put shims on each side of hammer. However if you end up a little tight then things don't go well at all as the trigger feel gets worse.

Do you have a trigger pull gage? If so check some pulls for consistency, if inconsistent you may have a poor alignment of trigger and hammer and it is 'pushing' the hammer in one direction. Fixing that will solve your problem I suspect. And I agree that a little minor chaffing is not a big issue.

Washers are not shims so the hardware store is not a place to go. The shim packs you can order from above site are in thousands of an inch and very consistent and are stainless steel I believe.

Hope that helps
Karl

 

[garbler]

Yes of course hammer rub is not unheard of but here is how it shakes out if you want a performance revolver. The hammer is the elephant in the lock-work room -- the heaviest and biggest part. If it rubs during its travel to DA lockup it is one more impedance to a smooth and lighter trigger pull and because of its size could be a major contributor. On the way down to ignition it's just a minor hindrance to lock time performance.

Regards

 

[prairieviper]

Thanks again everyone, for the help. I appreciate it.

 

[chief38]

#1) The shim's come in .001" increments
#2) the center hole must be the precise measurement
#3) they are usually made of Stainless Steel
#4) NOT a hardware store item.

 

[SW CQB 45]

my 586 hammer would move left at the start of the trigger press (DA).

I put a .002" shim on the left side and right….trigger press was very heavy and no return.

I took the right side out.

I have no side movement of the hammer at the beginning of trigger press. YAY!

 

[Rule3]

Many if not all have a little rubbing, with use it will wear down. Not a major issue,(to some it might be the end of the World)

As mentioned shims are not washers, of course there is always the angle grinder method!

 

[TAROMAN]

Another consideration is that the frame and/or sideplate may have burrs along their periphery.
These burrs can drag on the hammer.
I always make a point of stoning these areas smooth when tuning a revolver's action.

 

[Hapworth]

Most, though not all, S&W hammers I've examined had a little rub on them. The wear means the action has burnished and set. Only if it's demonstrably dragging and hitching trigger pull are shims called for, in my opinion; otherwise it's just normal wear, has a limit, and doesn't affect use.

 

[PPCSHOOTER]

SHIMS HELP, BUT THE REAL PROBLEM IS THAT THE DOUBLE ACTION SEAR WAS NOT CUT STRAIGHT DURING THE HARD FIT PROCESS. RECUTTING THE DOUBLE ACTION SEAR CORRECTLY THE HAMMER WON'T WOBBLE AND YOU DON'T NEED ANY SHIMS. JP

 

[garbler]

I did not think this thread would get legs or I'd have added a few points on hammer alignment. It is true the DA sear can marginally contribute to this condition but the real problems are the result of the following.

The hammer pivots and rides on a frame pin and riding shoulder or boss. They are found on both sides - the frame and side plate. On older guns these pins and bosses were pressed and fitted but now days they are machined as part of the frame or side plate. Installing shims not only helps center the hammer to the window but these shims must ride on the boss. If the boss is not cut true to the axis of the hammer or trigger pins then they will swing untrue. Adding shims will correct spacing problems but will aggravate or accentuate crooked bosses. Doing a first class action job means re-cutting and truing the bosses if necessary then shimming to center the hammer. The shims by the way do more than aid in centering a hammer they also reduce friction and provide a very slick bearing surface between the boss flat and hammer side.

Regards

 

[SW CQB 45]

I did not think this thread would get legs or I'd have added a few points on hammer alignment. It is true the DA sear can marginally contribute to this condition but the real problems are the result of the following.

The hammer pivots and rides on a frame pin and riding shoulder or boss. They are found on both sides - the frame and side plate. On older guns these pins and bosses were pressed and fitted but now days they are machined as part of the frame or side plate. Installing shims not only helps center the hammer to the window but these shims must ride on the boss. If the boss is not cut true to the axis of the hammer or trigger pins then they will swing untrue. Adding shims will correct spacing problems but will aggravate or accentuate crooked bosses. Doing a first class action job means re-cutting and truing the bosses if necessary then shimming to center the hammer. The shims by the way do more than aid in centering a hammer they also reduce friction and provide a very slick bearing surface between the boss flat and hammer side.

Regards

garbler,

just so I have a true understanding.

is the boss the raised area around the trigger and hammer pin and opposite side on the side plate?

if the bosses center the hammer and trigger, rough machining inside the receiver and side plate do not matter in the area of hammer and trigger travel/movement (as it will not make contact) correct?

so rebound slide contact with 3 sides is the only area that would need smoothing inside the receiver?

 

[garbler]

garbler,

just so I have a true understanding.

is the boss the raised area around the trigger and hammer pin and opposite side on the side plate?

if the bosses center the hammer and trigger, rough machining inside the receiver and side plate do not matter in the area of hammer and trigger travel/movement (as it will not make contact) correct?

so rebound slide contact with 3 sides is the only area that would need smoothing inside the receiver?

Sorry just saw your post. I'm a bit slow these days only a couple weeks out of shoulder replacement party. Anyway I am not sure what you are asking me and I'd guess it's my problem not yours. Can you try again

Regards

 

[SW CQB 45]

sometimes I confuse myself…sorry.

with the raised bosses around the trigger and hammer pin

the only true concern for inside receiver contact with a moving part is the 3 sides of the rebound slide….am I correct?

for trying to get the smoothest double action press.

thanks in advance

 

[garbler]

Mm

sometimes I confuse myself…sorry.

with the raised bosses around the trigger and hammer pin

the only true concern for inside receiver contact with a moving part is the 3 sides of the rebound slide….am I correct?

for trying to get the smoothest double action press.

thanks in advance

I think I understand now. Of course the rebound slide base and frame side are riding surfaces but the hammer bosses are too on a performance revolver. Learning to read the inside of a side plate can tell you volumes about anything that is rubbing including; hammer rub, front and rear leg of the bolt, hand out of adjustment, hammer stirrup too long, trigger pin too high, and trigger rub etc. the side plate gets scratched and rubbed when almost anything gets out of whack internally

Not sure how prevalent hammer boss problems are with the newer CNC milled parts but my personal 625 and 686's had some issues. In fact about 40% of the guns I worked on had rough bosses. The problem is the top of the boss is often rough from the cutter and there was no follow up polishing step. The hammer and trigger bosses acts as a internal spacers but also as a bearing surface for these rotating parts. Many of the rough bosses are also not machined true or flat which adds another dimension especially if you increase the surface area with shims. If you don't want a precision action job it's no big deal but I like my hammers falling where I tell them to . I never had a realistic method of determining which boss was high or low. If in theory you had a boss that was crooked or not parallel with the frame or side plate and let's say both the frame boss and side plate bosses were this way. If they are tall enough they will create friction and if one is too high it will push the hammer to one side of the window and rub. BTW I've never found an unaltered gun with factory bosses too low. But I have found revolvers where you could lighten the trigger pull by just backing off a tad on the side plate screws. In other words the hammer was being squeezed and not fitted properly.

When I see a hammer with scuff marks up between the spur and face it tells me the hammer is interfering with the frame in the upper portion of the frame window on the fall just before ignition. If the scuffing is lower and circular it usually means the hammer is off center all the way back. So I face off or true the bosses just a bit which helps center or align the hammer. This in turn provides a better surface for the shims as the hammer falls and as its cocked. Any little bit of friction or resistance in the lockwork is undesirable if you want an optimal action. It all adds up, 1/8 oz here 1/4 oz there and in the end you have a bag full of accumulated tolerances that mean the difference between a real action job and a spring kit swap.

These shims increase the bearing surface for the hammer to swing on and keep the mainspring, which is sort of this big unruly giant in the lockwork, from being able to push the hammer side to side. When you think about it that powerful flat spring is let loose on the hammer by a real wiggly stirrup connection none of which is very precision. If the hammer can wiggle side to side cause the bosses are out of the game then the mainspring will have its way with the hammer. On any of my action jobs there is no more than a few thousandths clearance between the hammer and frame window. You can could push all you want side to side and the hammer remains in the center. Try that with new guns or especially older guns with some wear and the hammer hits side to side. Sometimes you'll find a frame or side plate relieved too much and centering a hammer is tough . Other times you may get a hammer that is undersized or too thin but not often.

That's all I can think of
Regards