BigBill
Absent Comrade
I ask when I'm stumped wether the question is dumb or not.
Cylinder wear line
- Thread starter Rolandag2
- Start date
Oh, don't worry about it I have had plenty of ideas and thoughts that didn't pan out. Not being curious and asking questions is a way bigger mistake.
It is my understanding that the cylinder stop ball operates in a narrow area of movement. The trigger pulls it down at the bevel to release the cylinder. The ball should not be retracted below the frame, as it could get hung up and not return to stop the cylinder on the next chamber. So, lengthening the bevel as in your drawing would do exactly that. And even then, there is not enough movement in the cylinder stop to retard the cylinder stop enough to mitigate much of the line, I don't believe. Its amazing how all the parts work together to make a smooth running dependable revolver. Sometimes messing with one part throws a monkey wrench in the works.
look at Armorer951's pics, take his and Steelslavers advise and slightly and I mean slightly radius the leading edge of the ball and lightly polish the top as well. The sharp edge of the ball will "scrape" the cylinder as it rotates. After polishing it will "slide" in stead of scrape. This will not eliminate, but will reduce the severity of turn line.
lefty_jake
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Post #8 in this thread from @steelsaver makes some very interesting points about how chamber alignment, lateral cylinder play, and the forcing cone all figure into revolver accuracy. And how in S&W revolvers, the cylinder lockup is not supposed to have zero lateral play.
Some years ago I read a post about the lockup in Freedom Arms (FA) revolvers which really helped my understanding of this issue. FA is known for making the most accurate revolvers. And this post described how FA pairs each cylinder with a specific frame. FA has a mechanism which locks each frame in place, and then uses the frame as a jig to cut the chambers in the cylinder. Each chamber is cut, one at a time, and every chamber in that cylinder gets perfect alignment with that frame.
When I read about this method, I thought that a valuable trade secret of Freedom Arms was being improperly leaked. But it turns out that FA publicizes this system, and they want people to know about it. They know full well that no production revolver could compete with this method, it would just be too slow to scale up economically. FA can do it since their revolvers are semi-custom pieces priced at $2000 and up.
Learning about this helped me understand that extremely tight lock up might not be desirable. As @steelsaver describes, a tiny amount of play can compensate for necessary manufacturing tolerances. And these tolerances allow S&W to deliver an affordable product which is still far more accurate than most people can shoot.
Some years ago I read a post about the lockup in Freedom Arms (FA) revolvers which really helped my understanding of this issue. FA is known for making the most accurate revolvers. And this post described how FA pairs each cylinder with a specific frame. FA has a mechanism which locks each frame in place, and then uses the frame as a jig to cut the chambers in the cylinder. Each chamber is cut, one at a time, and every chamber in that cylinder gets perfect alignment with that frame.
When I read about this method, I thought that a valuable trade secret of Freedom Arms was being improperly leaked. But it turns out that FA publicizes this system, and they want people to know about it. They know full well that no production revolver could compete with this method, it would just be too slow to scale up economically. FA can do it since their revolvers are semi-custom pieces priced at $2000 and up.
Learning about this helped me understand that extremely tight lock up might not be desirable. As @steelsaver describes, a tiny amount of play can compensate for necessary manufacturing tolerances. And these tolerances allow S&W to deliver an affordable product which is still far more accurate than most people can shoot.
A practical approach:
CYLINDER 'STOP TRACK' MITIGATION AND CENTERING:
You'll see in other posts, that not all care about this issue and are quick to tell you. The cylinder line scribed by the cylinder stop is about the most obvious sign of wear. Not just a sign of shooting but also of cycling, opening for checking, or loading and unloading. If you aren't already aware, there are two things that you can do to mitigate or minimize cyl scribing or 'stop track':
1st HANDLING:
When you close the cylinder on a double action, with your left hand grasp it around the bottom of the frame with thumb and forefinger each in the cylinder flutes opposite each other. Position them at 3:00 and 9:00 o'clock just as the cylinder locks into place. The cyl stop will lock into the stop notch w/o having to rotate the cylinder with cyl stop rubbing on its surface. This will become a habit whenever you close a double action cylinder and you'll no longer have to think about doing it. This will prevent a FULL CYLINDER RING, limit it to an interrupted ring between cyl notches, and show a properly handled revolver.
2nd POLISHING THE CYLINDER STOP:
To mitigate "cylinder stop track" for all SA and DA revolvers - preventative action you can take and the 1st thing I do on any revolver of mine, new or used is pull the cylinder (or open it, in the case of DAs) and polish the cylinder stop!
Many come with file marks just waiting to carve out a line and groove in your cylinder finish! Stainless guns are the worst, they can gouge like aluminum. I have to look at the cyl stop surface with a 10 power jeweler's loop or my 10x gunsmith glasses (which are excellent eye protection as well) to truly see if the stop needs polishing. What looks good to my naked eye can be bad enough to mark up the cylinder. The sharp stop edges can really do damage and don't need to be knife edge sharp to function properly with a nice tight lock up.
Swing out or remove the cyl and I mask off the frame and breech face all around the stop with blue masking tape because I use a Dremel tool and it can slip off the stop. I wear my gunsmith 10x glasses and look for any irregularities. If there are any marks, I use a VERY FINE abrasive wheel in the Dremel tool to polish out the file marks, etc. I only advocate the fine abrasive wheel for removing tool marks in the surface of the bolt which can be pretty rough. It works very well in experienced hands and it's quicker; about 5 seconds. But I don't break the sharp edges with the abrasive wheel. And now is the time to change the contour of the stop ball if it needs slight re-contouring to center the 'stop track' in the cylinder notch leads and around the cyl. The highest point of the ball is where the 'stop track' is scribed. If the track is to the rear of center, a slight amount must be removed at the rear of the center of the ball to move the high point forward.
If no file marks, I go straight to polishing. With a little felt buffing wheel in the Dremel and white rouge (used for stainless steel) I put a mirror finish on the top surface. This is when I also address the sharp edges; I leave them nice and square but just dull the knife edge with the buffing wheel and the rouge. And I don't overdo it.
CYLINDER 'STOP TRACK' MITIGATION AND CENTERING:
You'll see in other posts, that not all care about this issue and are quick to tell you. The cylinder line scribed by the cylinder stop is about the most obvious sign of wear. Not just a sign of shooting but also of cycling, opening for checking, or loading and unloading. If you aren't already aware, there are two things that you can do to mitigate or minimize cyl scribing or 'stop track':
1st HANDLING:
When you close the cylinder on a double action, with your left hand grasp it around the bottom of the frame with thumb and forefinger each in the cylinder flutes opposite each other. Position them at 3:00 and 9:00 o'clock just as the cylinder locks into place. The cyl stop will lock into the stop notch w/o having to rotate the cylinder with cyl stop rubbing on its surface. This will become a habit whenever you close a double action cylinder and you'll no longer have to think about doing it. This will prevent a FULL CYLINDER RING, limit it to an interrupted ring between cyl notches, and show a properly handled revolver.
2nd POLISHING THE CYLINDER STOP:
To mitigate "cylinder stop track" for all SA and DA revolvers - preventative action you can take and the 1st thing I do on any revolver of mine, new or used is pull the cylinder (or open it, in the case of DAs) and polish the cylinder stop!
Many come with file marks just waiting to carve out a line and groove in your cylinder finish! Stainless guns are the worst, they can gouge like aluminum. I have to look at the cyl stop surface with a 10 power jeweler's loop or my 10x gunsmith glasses (which are excellent eye protection as well) to truly see if the stop needs polishing. What looks good to my naked eye can be bad enough to mark up the cylinder. The sharp stop edges can really do damage and don't need to be knife edge sharp to function properly with a nice tight lock up.
Swing out or remove the cyl and I mask off the frame and breech face all around the stop with blue masking tape because I use a Dremel tool and it can slip off the stop. I wear my gunsmith 10x glasses and look for any irregularities. If there are any marks, I use a VERY FINE abrasive wheel in the Dremel tool to polish out the file marks, etc. I only advocate the fine abrasive wheel for removing tool marks in the surface of the bolt which can be pretty rough. It works very well in experienced hands and it's quicker; about 5 seconds. But I don't break the sharp edges with the abrasive wheel. And now is the time to change the contour of the stop ball if it needs slight re-contouring to center the 'stop track' in the cylinder notch leads and around the cyl. The highest point of the ball is where the 'stop track' is scribed. If the track is to the rear of center, a slight amount must be removed at the rear of the center of the ball to move the high point forward.
If no file marks, I go straight to polishing. With a little felt buffing wheel in the Dremel and white rouge (used for stainless steel) I put a mirror finish on the top surface. This is when I also address the sharp edges; I leave them nice and square but just dull the knife edge with the buffing wheel and the rouge. And I don't overdo it.
Just got a brand new, in the box, never fired 431PD and it already had a turn line. I guess I will have to keep looking for that magic Smith without one.
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