S&W Revolver Timing Issue

[Clarke123]

I have an S&W 64 that appears to have a timing issue:

The double action appears to be dead-on, the single action appears to be slow.

 

[jeep78]

Usually it is the other way. Take off the side plate and check for broken trigger or hammer stud. Check that the hand spring is properly installed. Check for chipped or worn hand, and clearance between hand and frame at hand window (use feeler gauge). Check cylinder pawl notches on cylinder, and locating pins on cylinder. Check for excess headspace and bent cylinder crane and axle.

 

[jeep78]

Also, make your checks with empty brass in the chambers, you will get errors if not loaded with brass.

 

[Clarke123]

Usually it is the other way. Take off the side plate and check for broken trigger or hammer stud. Check that the hand spring is properly installed. Check for chipped or worn hand, and the clearance between hand and frame at hand window (use feeler gauge). Check cylinder pawl notches on cylinder, and locating pins on cylinder. Check for excess headspace and bent cylinder crane and axle.

The insertion of "Brass" in the newer models (without extractor pins) is an interesting point, but it didn't seem to perform anything differently: still "slow" on Single-Action, and dead-on on Double-Action! The "Hand" channel/slot clearance seems flush - doesn't appear to stick out beyond the face (where the firing pin resides) though. However, the "head" of the "Hand" looks a little rough. Further, removal of the side plate shows a lot of burnt lubricant buildup. A flush with brake cleaner didn't do more than making a dent in it ... I'm tempted to soak the whole thing in Mineral Spirits overnight.

I can get a new "Hand" from Numerich (oversized/otherwise?) ... Any suggestions on additional spare parts? Then again, I hesitate to disassemble the thing as I am not experienced with the internals of a revolver ... looks like a lot of small parts/springs in there!

Hey, I really appreciate the advice!

 

[Horsehat]

The insertion of "Brass" in the newer models (without extractor pins) is an interesting point, but it didn't seem to perform anything differently: still "slow" on Single-Action, and dead-on on Double-Action! The "Hand" channel/slot clearance seems flush - doesn't appear to stick out beyond the face (where the firing pin resides) though. However, the "head" of the "Hand" looks a little rough. Further, removal of the side plate shows a lot of burnt lubricant buildup. A flush with brake cleaner didn't do more than making a dent in it ... I'm tempted to soak the whole thing in Mineral Spirits overnight.

I can get a new "Hand" from Numerich (oversized/otherwise?) ... Any suggestions on additional spare parts? Then again, I hesitate to disassemble the thing as I am not experienced with the internals of a revolver ... looks like a lot of small parts/springs in there!

Hey, I really appreciate the advice!

I usually find disassembly to be a snap.

 

[Clarke123]

Videos that seem applicable:
(Note that the "Potterfield" Videos tend to "over-simplify"!)

Kind of makes you want to have a "Gunsmith Opinion" on ANY used revolver acquisition!

 

[Clarke123]

Geeze! ... I now know more about revolvers than I EVER wanted to know!!!
I also know that the periodic pulling of side-plates is mandatory for the good health of
S&W Revolvers ... That, and finding out that I never knew that powder residue could become petrified!

It is truly amazing that semi-auto pistols were invented AFTER revolvers ...
Kinda like helicopters coming before fixed-wing aircraft!

 

[Clarke123]

OOPS!

I guess I forgot all about mechanical adding/multiplication machines ... If you've ever seen and operated them, then "mechanical genius" is an appropriate term!

 

[jeep78]

The insertion of "Brass" in the newer models (without extractor pins) is an interesting point, but it didn't seem to perform anything differently: still "slow" on Single-Action, and dead-on on Double-Action! The "Hand" channel/slot clearance seems flush - doesn't appear to stick out beyond the face (where the firing pin resides) though. However, the "head" of the "Hand" looks a little rough. Further, removal of the side plate shows a lot of burnt lubricant buildup. A flush with brake cleaner didn't do more than making a dent in it ... I'm tempted to soak the whole thing in Mineral Spirits overnight.

I can get a new "Hand" from Numerich (oversized/otherwise?) ... Any suggestions on additional spare parts? Then again, I hesitate to disassemble the thing as I am not experienced with the internals of a revolver ... looks like a lot of small parts/springs in there!

Hey, I really appreciate the advice!

An oversize hand will likely need fitting. NOT for someone unfamiliar with working on revolvers.

"Standard" hands have some variations in dimensions due to tolerance. I have seen 6 thousandths difference in hands on Smith and Wesson K frames.Having several hands and swapping them out is an easy way to fix timing, it that is where the problem lies. Filing on the frame is a one way adjustment, and is done to fit an oversize hand.

As mentioned, a good cleaning is always a good first step.

 

[Clarke123]

An oversize hand will likely need fitting. NOT for someone unfamiliar with working on revolvers.

"Standard" hands have some variations in dimensions due to tolerance. I have seen 6 thousandths difference in hands-on Smith and Wesson K frames. Having several hands and swapping them out is an easy way to fix timing, it that is where the problem lies. Filing on the frame is a one-way adjustment, and is done to fit an oversized hand.

As mentioned, a good cleaning is always a good first step.

Oh, I agree! I wore-out a bronze brush cleaning this one! That and using a Chore-Boy copper pad. Even afterward, I am still puzzled about the double-action being dead-on and the single-action being slightly off.
I should have spotted this when I picked this weapon up, but it was so slight that I seem to have missed it.
The price was such that I have to admit that the "education value" will likely be well worth it!

I agree that changing "Hands" alone is a tedious enough undertaking. This, without having to polish/grind the danged thing! I ordered an over-sized hand from Numerich but will likely seek
out a local "expert" to do the work. They may find that the extractor is the culprit: that's a whole new ballgame in terms of experience!

I live in Cumming, GA ... Anyone have some suggestions for someone who is both good and reasonable?