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07-03-2011, 07:29 PM
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Model 624 cylinder ring galling - WHY?
Happy Independence Day to all.
A situation is beginning to surface on the cylinder of my beloved Lew Horton model 624 .44 Special that I am not to happy
about and am a little concerned with. I am noticing that where the cylinder stop rubs on the cylinder and creates the "ring"
around the cylinder between the stop notches there appears to be what I would call galling of the cylinder surface. In other
words there is roughness that you can actually catch your fingernail on in two places on the ring between two notches.
One (the worst) is shown in the photo below.
What I can't understand is why it only occurs in two places and not on each place that the cylinder stop pops up
and contacts as the cylinder rotates.
All but two of my guns are either blued or nickel plated so I am not that familiar with how stainless steel guns normally wear
on the cylinder. The turn lines on my other guns are smooth regardless of the amount of wear. To those of you more familiar
with stainless is this common? I am thinking this roughness will get worse with use.
My Questions:
How can I smooth this area without ruining the finish on the cylinder, or should I?
I could stone the sharp leading edge of the cylinder stop to create a slight chamfer, is that recommended?
As always I appreciate your comments and advice. Bob
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07-03-2011, 08:39 PM
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Others will probably post with better suggestions but it looks to me like your cylinder stop is rough or has a burr, slight dimensional differences in the cylinder itself is causing the galling to be worse in the 'high' spots on it.
Before you resort to stoning, try this trick, get a hard eraser from Staples or one of the office supply places and use it to 'polish' the surface of the cylinder stop, These erasers are just hard rubber with an abrasive grit embedded. Check the stop for obvious flaws or burrs and rub the eraser, which you can cut into small long pieces, on them. That will take them down slowly without removing too much metal. Just polish it, don't get real aggressive and be careful not to contact the surface of the gun unless you've taken the stop out, which is tricky in itself.
I've had good luck polishing the surfaces of the stops like this.
Also, you may have a build up of gunk under the cylinder stop itself that is forcing it up, a good cleaning while looking for the burrs may help as well.
RD
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07-03-2011, 10:37 PM
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Thanks RD,
I agree that the stop needs polishing and that is a great idea about the ink eraser.
Any other ideas as to how to clean up the cylinder? Bob
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07-04-2011, 12:00 AM
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I am puzzled why this would only occur in between two of the stop notches? Is the problem getting worse, or did it seem to appear out of the blue?
While polishing the stop certainly won't hurt, the stop alone is unlikely to be the cause of the problem (as you describe it).
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07-04-2011, 12:52 PM
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Quote:
Originally Posted by ExMachina1
I am puzzled why this would only occur in between two of the stop notches? Is the problem getting worse, or did it seem to appear out of the blue?
While polishing the stop certainly won't hurt, the stop alone is unlikely to be the cause of the problem (as you describe it).
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I am not a smith. I have a one year old (300 rounds) 642 showing slightly similar conditions.
My current 642 exhibits some 'eccentric-ness' when I spin the cylinder, and I noticed that the stop doesn't 'click' into the cylinder the same for each slot on the cylinder - two are before the hammer drops, one is at the same time, one I cannot tell. My stop ring on the cylinder is to me noticeably deeper on one side. But it is not galling.
Now, I have been in automotive component manufacturing quality for a bazillion years so .001" is very noticeable to me. I estimate my 642 cylinder is about .003" - .004" off center. If I spin it fast enough the whole gun actually moves in my hand. The groove depth is about .002" different.
Your cylinder might be mounted off center like mine, which is why the galling looks to be 'one-sided.' But the cylinder stop is what is scraping the cylinder, so I would check for a sharp edge, or an adjustment you can make to lower the stop a couple of .001" if that is possible.
The other question I would ask is can the stop hit the cylinder differently as the cylinder rotates? Is that possible? Can it retract lower sometimes, and higher other times as the cylinder revolves, AND to the same high spot in conjunction with the same spot on the cylinder?
And I hope you can get that repaired or replaced. Nice looking gun!
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Marty 4513TSW 13-1 642 60-10
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07-04-2011, 07:05 PM
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Quote:
Originally Posted by MAG-NUM
Thanks RD,
I agree that the stop needs polishing and that is a great idea about the ink eraser.
Any other ideas as to how to clean up the cylinder? Bob
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You can safely use 320 or 400 grit wet/dry sandpaper to take out the blemish and smooth out the surface, then go over that with 600/800 grit to remove the marks from the 400 grit. Polish with a polishing paste like Fitz or Maas, and then follow that up with 3M white Scotchbrite pads to burnish the area to match the rest of cylinder making sure that you go in the same direction as the existing factory buffing swirls. You'll need to "experiment" with how much pressure to use with the pad, I found being light handed worked the best.
I did that on a used 629 I bought that had a light ding in the cylinder... you can't tell it was ever there.
BTW... the trick with the ink eraser also works to clean off oxidized electrical connectors and fuse box contacts exposed to the elements (autos, motorcycles, etc) to cure problematic circuits.
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Conrad
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07-05-2011, 06:25 PM
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Quote:
Originally Posted by Martya
My current 642 exhibits some 'eccentric-ness' when I spin the cylinder, and I noticed that the stop doesn't 'click' into the cylinder the same for each slot on the cylinder - two are before the hammer drops, one is at the same time, one I cannot tell. My stop ring on the cylinder is to me noticeably deeper on one side. But it is not galling.
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Thanks for your observations Marty. As best as I can tell with the naked eye, the cylinder spins very true, I don't see the least bit of wobble. This gun has had light use and functions flawlessly.
Gunhacker, thanks for the tips on polishing the cylinder. I will do this along with deburring the stop and hopefully this will stop the galling.
Thanks for everyone's input, Bob
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07-05-2011, 06:57 PM
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Have you checked with S&W to see if your gun is one of the ones with bad heat treat? You can call with the serial number, and ask if it's one of those.
EarlFH
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07-05-2011, 07:10 PM
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Bob,
All good suggestions from those above. Maybe this will be a little additional help.
SS is relatively soft and therefore similar to aluminum when it is machined in that it has a tendancy to gall as you correctly identified. Therefore unpolished surfaces of machined parts like the bolt will often be rough and sometimes look like a file!
The very 1st thing I do to any revolver used or new, blue or SS is to polish the cylinder bolt to a mirror finish. This is especially important on SS guns.
First I tape the frame around the bolt with masking tape so I can do it in the gun w/o accidently touching the frame. Then put on my 10X glasses; very important!
Smooth it with 600 grit paper wrapped around a flat metal surface being careful not to round the bolt edges or change the contour until any machine marks are gone, then 1000 grit. Then use a Dremel tool with a 3/4" diameter felt buffing wheel and stainless steel white rouge to buff parrallel to the bolt's edges to a brilliant shine. This will slighty de-knife-edge the bolt edges w/o focusing the wheel on the edges which would round them off. If you don't have a Dremel tool, finish off with 2000 grit paper and polish with Flitz or Semi-chrome polish; even toothpaste.
This has mitigated the cylinder ring on my guns and delayed the bolt from even wearing all the way thru the bluing on a new gun for years of shooting.
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Jim
S&WCA #819
Last edited by Hondo44; 07-05-2011 at 07:15 PM.
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07-05-2011, 08:58 PM
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Quote:
Originally Posted by EarlFH
Have you checked with S&W to see if your gun is one of the ones with bad heat treat? You can call with the serial number, and ask if it's one of those.
EarlFH
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My gun does have the red circle C stamp on the end of the serial matching box, therefore I believe it's been checked. Thanks
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07-05-2011, 09:02 PM
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Quote:
Originally Posted by Hondo44
This has mitigated the cylinder ring on my guns and delayed the bolt from even wearing all the way thru the bluing on a new gun for years of shooting.
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That is an excellent idea and a well written procedure, I will give this a try. Thanks, Bob
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