Fitting oversize hand to N-frame. Please critique.

[GregG]

I bought my Model 58 about 4 years ago. The gent told me he had shot it a lot. When I got it it wouldn't lock on two cylinders unless cocking the gun fast. Hand was worn. I bought an oversize hand from Brownells, it was a Power Custom unit, and I fit it to the best of my understanding at the time. It functioned but later I realized I could have done a better job.

So I bought a new one, and proceeded to install it right. This is what I did over the weekend:

This gun had a timing problem. It undertimed. With the gun cocked I could look into the bore and see a little of the *port* side of the cylinder throat. I addressed that first and narrowed the cylinder stop with a stone until the cylinder could rotate enough to center the throat on the bore.

Then I narrowed the hand until it worked with the most *retarded* notch. Then I fit the other notches to fit.

The cylinder has some play uncocked, but cocked all them are tight and centered on the bore, best as I can tell.

Thanks for any criticism.

 

[500 Magnum Nut]

First, you should never stone down the stop, unless the alignment is off. Range rods will check the alignment.
2nd adjust the endshake if it's off.
Then fit the new hand. If the hand is binding on a few positions, you adjust the ratchets, make sure the range rods tell you so.....

I don't have much time for a detailed response right this minute, so others will fill in the blanks for you. I have some stuff in the faq sticky above, this will get you started.

 

[GregG]

The stop had to be stoned. It was locking the cylinder in a mis-timed position.

 

[Jeff in Cincinnati]

Unless things have changed since I went through S&W Armourer's school (which admittedly was many years ago), the timing of when the cylinder stop retracts and "pops up" can be adjusted by very carefully stoning the surface that rides on the trigger as the trigger is pulled and released. However, this adjustment did not affect the alignment of the cylinder with the barrel. As far as I recall, the only tuning of the cylinder stop was to perhaps very gently break the sharp corner of the portion that engaged the notches in the cylinder. So, adjusting the width of the cylinder stop would have been a no-no. As I recall, barrel cylinder misalignment was repaired by adjusting the yoke first to make sure it was aligned. There was/is a special tool for this that fit inside the yoke and would drop in the bolt hole in the breech face when the yoke was aligned. Then, a range rod could be used to check the charge hole alignment -- but again, I believe the adjustments were done to the yoke.

Fitting ratchets is one of the more delicate adjustments to a S&W revolver. A little too much, or the wrong angle and you are sunk.

My experience predates the MIM parts, so I can't say for certain that the methods I learned apply to the new generation of parts, but I suspect the differences are not great.

Good luck.

 

[ken158]

Jeff is correct on all comments. Been there and done that. Once you have cut ratchets and gone past the point of no return (larger hand wont bring it into spec) you will need a new ratchet (star) installed. I fondly recall cutting so many ratchets at the academy that we all bought leather gloves to keep our palms from bleeding... Working on a S&W can be like rebuilding the engine in your car without proper knowledge and tools.

 

[GregG]

Very interesting. Thanks.

The cylinder stop is cheap, and I can always put another back in. In fact I have an oversize one I bought along with the hand. I fit it before installing this new hand, and of course the cylinder/barrel alignment did not improve. The cylinder had less play. That was it.

It's almost like several tolerances are *stacked* in the same direction.

I'll investigate the yoke situation.

Thanks.

 

[GregG]

Jeff, I think I'm absorbing what you said. It's like a bulb turned on after a few hours.

I think the final answer to fixing this gun is to put the tight fitting cylinder stop back in, and adjust the yoke to fine tune the cylinder/barrel alignment.

Luckily I'm a machinist and can make a tool to do this.

Many thanks for the enlightenment.

 

[500 Magnum Nut]

They sell an alignment plug for this.

You remove the cylinder and slide the gage down into the breech end of the gun. Then you twist the yoke to get it squared up.

BROWNELLS : YOKE/CRANE ALIGNMENT TOOL - World's Largest Supplier of Firearm Accessories, Gun Parts and Gunsmithing Tools

It should slip down all the way without touching the sides. It's easy to tell which way your off.

Fitting the stop is done with the cylinder notches, and the narrowest notch is what you select as your stop width.

There is a way to stretch the frame by peening around the frame opening of the stop, this will tighten up the stop if there is excessive movement with it.