Replace Cylinder

[chapnelson]

I think I'd like a fluted cylinder on my 629-5. I'd say I'm fairly handy; done a spring job before, and minor tune up on some other guns. How difficult is a cylinder swap? Would you recommend I have a smith do it, and who?

And what do you do with the leftover parts when you're done?

Mahalo, Chaps

 

[500 Magnum Nut]

This is one part of the gun which is custom fit on every revolver.
Things to fit are B/C air gap, extractor, extractor rod, timing & head space.

You might get that new cylinder to fit perfectly, but it's very unlikely.

In addition, S&W won't sell extractors to anyone outside the factory. The guns need to be sent in for an extractor repair/replacement.

 

[Alk8944]

This is one part of the gun which is custom fit on every revolver.
Things to fit are B/C air gap, extractor, extractor rod, timing & head space.

You might get that new cylinder to fit perfectly, but it's very unlucky.

In addition, S&W won't sell extractors to anyone outside the factory. The guns need to be sent in for an extractor repair/replacement.

Used to be.

On the "Square Extractor" guns, and the 629-5 is one, S&W will sell cylinders and extractors. These are CNC parts and there is a good chance they will drop in. There may be minor fitting required, but nothing like in the past.

This is not my opinion, but information from S&W customer service.

 

[500 Magnum Nut]

I checked the parts book, thinking to myself, no way....

Yep, your correct on the new extractor!

09 213810000 $34.87 X EXTRACTOR - NEW STYLE


thanks for the clarification!

 

[tomcatt51]

Your 629-5 should be a MIM FMFP gun. Just buy a cyl assy and re-use the extractor in the gun. The new cylinder will probably drop in needing only checking and adjusting the endplay and checking the barrel/cylinder gap.

 

[scooter123]

I would recomend purchasing a complete cylinder assembly from S&W. These modern guns are so consistent from gun to gun that it's extremely likely that a complete assembly will drop right in without any requirement for fitting.

As for why, I have two reasons for this suggestion. One is that it allows you to change out the cylinder if the mood hits. The second is that I discovered that the extractor rod on my 610 uses a multi-start thread and on the cylinder in my 610 the threads are "clocked". This means that the extractor will only thread in properly if I start the threads at the correct rotation, in any other position, it will start and then bind up after 1/2 to 1 1/2 turns depending on the position. If this is the case for every extractor rod, this means that they may require fitting of the thread with lapping compound and that can be a delicate and time consuming operation.

 

[borntoraisehogs]

I made a nice pencil holder from my old cylinder . Capacity six .

 

[tomcatt51]

I discovered that the extractor rod on my 610 uses a multi-start thread and on the cylinder in my 610 the threads are "clocked". This means that the extractor will only thread in properly if I start the threads at the correct rotation, in any other position, it will start and then bind up after 1/2 to 1 1/2 turns depending on the position. If this is the case for every extractor rod, this means that they may require fitting of the thread with lapping compound and that can be a delicate and time consuming operation.

I believe they're a double lead thread on the extractor rod and extractor. You have to actually push them together as you turn them to start the thread to get both threads engaged. Get just one engaged and you have Scooter123's "bind". They are not "fitted" and you absolutely don't want to use lapping compound.

 

[scooter123]

My impression is that it's a 3 start thread. In one position it will bind after only 1/2 turn, in the next position it will turn 1 1/2 turns and then bind, then finally in the final position it will thread in freely. However, this is all by "feel", my near vision is lousy. Some time I may dig out my 10X loupe from wherever I stashed it and take the time to count the starts. What I have found is that after I find the 1 1/2 turn bind I can push in and rotate clockwise until I feel a distinct "click" and it will thread in perfectly.

What puzzles me is the reason why they chose to use a multi start thread on this part. One problem with multi start threads is that they are less resistant to vibrating loose than a single start thread of the same pitch. Since a loose ejector rod will prevent the cylinder from releasing, I would think they would have used a single start thread for this application. It would be interesting to know the history behind this decision because I am sure it was done for a good reason.

BTW, I have had to hand lap threads on a few occasions and it's such a PITA that I kept fiddling with the extractor until I figured out an easy method to get the cylinder back together.

 

[tomcatt51]

Left hand 3/16-48? Not very nicely cut but not double lead like I thought it might be.

 

[Nightowl]

I am more accustomed to fixing guns than changing cylinders and barrels. But, I had a new cylinder installed and the old cylinder is extremely tight fitting using the old yoke that the new cylinder works well with. i would recommend getting the whole unit, yoke, extractor and all and fitting each to the gun. That is, if you want to keep the old cylinder. I thought it might be needed at some point in time.

I had Smith fit mine and it was just over $200 with shipping, so for that money, I wouldn't even mess with it myself.

 

[chapnelson]

Your 629-5 should be a MIM FMFP gun. Just buy a cyl assy and re-use the extractor in the gun. The new cylinder will probably drop in needing only checking and adjusting the endplay and checking the barrel/cylinder gap.

Got the MIM, but what's FMFP? Appreciate the advise; I think I'll price the whole assy and see what Smith charges in comparison.

Mahalo!
Chaps

p.s. when it comes to guns I get a very rare and specialized version of ADD ... if I don't follow through right away, I can have multiple projects in various stages cluttering up the bench. I tell my wife there are worse things I could be doing!

 

[tomcatt51]

Got the MIM, but what's FMFP?

frame mounted firing pin

 

[chapnelson]

roger, thanks!

 

[JC Garand]

frame mounted firing pin

I thought it was "Fleet Marine Forces Pacific", good to know another meaning for this.