Where to get an oversized hand?

dr. mordo

Member
Joined
Jul 18, 2017
Messages
1,677
Reaction score
2,962
Location
Miami, FL
I have a M37 that doesn't lock up, and I want to try an oversized hand. However, a google search is not turning any up for some reason.

Where do you get yours?
 
Register to hide this ad
You might try S&W Customer service. The part number will be 0707801.

Check also to make sure your model 37 doesn't have excessive end shake.....over .002". If it does, you might try repairing the end shake first, to see if that will help with the carry up issue.

If S&W doesn't have any OS hands, measure the width of the throat area at the top of the hand that is in the gun. I may have one I could send that would be .001"-.002" over what you currently have, which may solve the problem. Standard width J series hands are typically .073" - .075". Oversized OEM's are usually in the .078" - .080" range.
 
Last edited:
Isn't 'stretching' the old hand possible?
In old double action Colt revolvers that have V mainsprings carry up is advanced by stretching the hand. In S&W revolvers carry can be advanced by peening the extractor's ratchet lugs. Few amateurs do that. Just like bending the frame to correct windage, I would not practice on an expensive revolver.
 
I have more examples of J and K series hands, because those are the frames I serviced most often during what I'll affectionately call the "revolver era" of my police armorer service. You know, back when dinosaurs roamed the earth.

Sizes (nominal width at the throat) are as follows:
J - .073" - .075"
K, L, and N - .093" - .095"
 
Last edited:
Smith and Wesson revolvers carry up on the "width" of the hand at the throat, or top portion of the hand, not via the hand's OAL. "Stretching" the hand by peening would not have the desired effect.
Agreed, considering what little I know. Some people believe that a hand can be effectively thickened by bending it in the middle. See Brownell's Gunsmith Kinks III, pages 276-7. Others say you'll break the hand before you get it to work. My limited experience (at least once, maybe twice) is that it can work.
 
There are 2 unconventional ways to widen a hand that do work, but should be considered as emergency field fixes only until they can be redone correctly. These are NOT the professionally approved way of doing things.

One is to bend the hand very slightly to the left with it on the trigger. The hand won't bend, but the pivot pin will. This puts the hand closer to the center pin and advances the timing slightly. As the hand pushes the ratchet up, it goes out and around the ratchet when the cylinder locks.

The other way is to file or mill a small step (.002 to .003) in a block of steel. Make a hold down clamp and drill a clearance hole for the pins on the hand. The hand should sit so that the top nose part is hanging out over the step. Then clamp the hand down on the block and heat the nose area to orange and forge the nose down to the lower level. When it cools, the top of the hand will be offset by the amount of the step in the steel block. Fitting can proceed from there.
 
In the method mentioned in post #12, the hand is completely removed and bent by smacking it in the middle, using a heavy machinist's hammer on a rounded-off chisel, while supporting the two ends, maybe on an open vise or something similar. This precision process is monitored with a decent vernier (or dial) caliper which measures in thousandths. In my case, it didn't need to be bent much.
 
In my experience, bending the hand by "smacking it in the middle" will likely result in two outcomes: the hand will break or crack, or, if the bend is successful, the "reconfigured" hand will bind in the hand slot in the frame. (which will then necessitate the removal of material from the hand slot)

If the cylinder is not carrying up properly, the simple and preferred fix is a slightly wider hand, measured at the throat. Usually, only .002" - .003" of additional width is required, and this additional width can easily be accommodated by the hand slot. An oversized hand may not be necessary.
 
Last edited:
Fitting an oversized hand is not a job easily accomplished. First off as Armorer951 said they don’t bend only break cause they are hardened as in file proof and stone only. Even if you could bend the hand in the middle think about it’s fit in the window ? Can’t imagine a critical timing part like this only riding on the high spot in the middle ? Every competition action job I did included an oversize hand carefully fitted to the extractor lugs to provide positive carry up and lockup for staging if wanted.

Localized high temp heat and a fixture such as Protocol Design notes and the hand nose or tip can be bent or offset. The hand must be fitted to the lowest lug only and the hand and window stoned fitted to provide no slop or play. Any lateral slop or play would allow the hand to push off and skip or carve up the ratchet lugs. Any hand protrusion out of the recoil shield is unacceptable and not enough is just as bad. Removing material from the hand belly will regulate depth. Again it’s a hand stoning job. For stoning a hand’s thickness I used a small surface grinder but careful hand stoning works as it should but it’s slow tedious work.

Bottom line is that fitting up a oversize or competition hand requires probably more careful fitting than any other job on these revolvers. But when done right the guns carry up and lock up are worth the effort and valued by comp shooters

Good luck
Rick
 
Back
Top