Does this revolver need a slight tuning?


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Crawdad1
December 2, 2012, 11:31 AM
I have a '62 Police from Uberti that when revolved the stop bolt hits on all chambers. Occasionally, one specific chamber will ride past the cylinder stop bolt and become unaligned and I have to grab the cylinder with my hand and move it back (counterclockwise) in order to align this chamber with the hammer and barrel. This only happens occasionally, does this revolver need to be tweeked a little or do I need to tune this revolver or just live with it?

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unknwn
December 2, 2012, 03:45 PM
For starters, mark the chamber that it occurs on with a piece of tape or a China marker and find out if it only happens on that specific chamber.
That can help you learn something about the potential problem.

rcmodel
December 2, 2012, 03:57 PM
If the bolt actually fits full depth in all the locking notches in the cylinder?

Then you probably have a weak or cracked trigger/bolt spring.

rc

Crawdad1
December 3, 2012, 02:17 AM
Thanks guys, I'll start looking more closely at it to make sure that it is the only chamber that is riding past the stop bolt. I do have a replacement spring also.

Hellgate
December 3, 2012, 02:25 AM
If it's not the spring then you are gonna ned to fiddle with the bolt but lets see what happens with it first.

Old Fuff
December 3, 2012, 10:35 AM
Back during the 19th century Colt final assemblers would start by adjusting the length of the trigger so that when the tip of the trigger engaged the full-cock notch the back of the hammer would be against the top of the backstrap. This is an important point that is largely ignored today.

Next they would adjust the length of the hand so that it would rotate the cylinder from one notch to the next, but no further.

When the lockwork was adjusted in this manner the backstrap prevented the hammer from going backwards far enough to cause the condition described in the opening post.

To answer the question, yes - the action should be retimed.

tscmmhk
December 3, 2012, 10:57 AM
Old Fuff,

Would you have the entire procedure the 19th century Colt factory assemblers used in assembling / tuning C&B revolvers? I think this is good info that a lot of people don't know about.

Thanks

Crawdad1
December 4, 2012, 09:46 AM
You guys are right I should have determined if it is only one chamber that is riding past the stop bolt before asking this question.

But, after determining if it is the same chamber that is sliding past the stop bolt then you’re saying that the 'throw' of the hand should be adjusted before the cylinder stop bolt or spring?

Old Fuff
December 4, 2012, 11:51 AM
Would you have the entire procedure the 19th century Colt factory assemblers used in assembling / tuning C&B revolvers? I think this is good info that a lot of people don't know about.

Well there are some here that claim I know becaues I was there at the time... :D

The truth is that when I was a "young" Fuff I met an elderly gentleman who had a grandfather that worked at the Colt factory during part of the late cap & ball era. By watching what he did I learned how and why.

Some time back I posted a more complete description on another thread, and it generated absolutely no interest. Duplicating these things takes time that I don't always have. I will go back though and see if I can find my post in the earlier thread, and if successful post a copy here.

=====================

If the problem of the bolt over riding the notch is limited to just one chamber the reason may be a mis-fit between the hand and one ratchet tooth (in which case the tooth should be modified) or more likely, the particular notch is battered and peened out.

The real clue to look for is that when the bolt has entered the cylinder notch is the hammer all of the way back against the backstrap. Usually you will find it isn't. Now the hand is trying to still rotate the cylinder but can't. This is a sure fire way to end up with battered notches.

Hellgate
December 4, 2012, 12:22 PM
Fuff,
I wanna get your approval on this but shouldn't he just take a hair off the bolt leg that rides over the hammer cam so the bolt comes up earlier to lock the cylinder in place. It looks to me that his bolt is rising a little too late so it skips. The other stuff with the hand or ratchet teeth I'm sure are contributing to the problem. I have "solved" several chamber skipping problems by working the bolt leg. Maybe not the ideal fix but a "good nuff" fix for an amateur like me.

Old Fuff
December 4, 2012, 12:49 PM
Here's the problem - maybe. Trouble is I don't have the gun in front of me.

The original Colt's were assembled so that when the tip of the trigger dropped into the full-cock notch the back of the hammer came up against the backstrap and couldn't rotate any further. They did this by using what was called "selective fitting," and picking a longer or shorter trigger. Next, the tip of the hand was adjusted so the the cylinder would rotate from one notch to the next, but no further. This eliminated any possibility of the ball on the bolt battering or peening the notch, or the bolt over riding and skipping the notch. After that they fitted and timed the bolt.

It may be that in this case the bolt is releasing too late, and the tail of the bolt can be modified to affect an earlier release. But this won't help if the core problem is the hand can try to continue to push against the ratchet tooth when the hammer isn't blocked by the backstrap.

TheRodDoc
December 4, 2012, 09:43 PM
Why does the trigger length have much to do with the timing as long as it catches the hammer when cocked? It seems to me not have too much to do with the timing.

If it drops into the hammer a little early, why would that make any difference?

You should be able to adjust all timing without the trigger even in the gun.

If when you pull the hammer to full cock till the frame stops it and the cylinder slot has rotated a little past the bolt then the hand can be shortened some. This will fix the problem of the bolt nicking the exit side of the cyl. notch at the beginning of the cock cycle. Also easy to tell if the hand is too short at this time. (if it didn't rotate the cyl, quite to the bolt).

Then when that is correct, adjust the bolt leg length to drop the bolt in the led ramp of the cyl. a little sooner.

I drew an animation of the action of a Colt cycling. It is a QuickTime movie. You can move the action with your mouse by grabing the slider and moving it.
If it works it might help some figure out the basics of the parts and how they work together.

http://www.theroddoctor1.com/180.mov

mykeal
December 4, 2012, 10:03 PM
1. The hammer does not contact the frame in the vast majority of the replicas.

2. Given the above, the length of the sear most certainly defines where in it's arc the hammer reaches full cock, and the location of the hammer in it's arc affects the bolt position and hand position. That's timing.

3. Your link is misspelled. It's missing the colon after http.
http://www.theroddoctor1.com/180.mov

4. Excellent graphic, very well done. Unfortunately we can't see the sear enter the full cock notch.

Can I use the link (with attribution, of course)?

TheRodDoc
December 4, 2012, 10:38 PM
The last little movement of the hammer does not affect the bolt. It has already dropped from the hammer. I realize some repo's don't let the hammer stop at the frame. But to fix the nicking at the exit side of the cyl. slot all you have to do is shorten the hand .

If you watch the trigger in the movie you can see when it snapped into the hammer notch. (move the movie slider slowly).

You may use the link if you want, But if it to many view it it may exceed my band with and I would have to remove it. But till then OK.

Old Fuff
December 4, 2012, 11:07 PM
Why does the trigger length have much to do with the timing as long as it catches the hammer when cocked? It seems to me not have too much to do with the timing. If it drops into the hammer a little early, why would that make any difference?

Assemble the following in the frame (including the cylinder and barrel).
Hammer
Hand
Backstrap

Now while looking through the window where the bolt's ball would usually be, align one of the cylinder notches with the window.

Next, slowly cock the hammer until it is stopped by hitting the backstrap, and see if the hand doesn't rotate the cylinder past the next notch.

The way Colt built these revolvers this wouldn't happen. The hand would be fitted so that at the exact point where the backstrap stopped the hammer's rotation the next notch in the turning cylinder would come up and be alligned with the frame's window.

When this is done the cylinder won't develop battered/peened notches, nor will the cylinder over carry and skip notches.

At this point you can fit and time the bolt.

TheRodDoc
December 4, 2012, 11:32 PM
That is what I just said in my posts. Adjust the hand then the bolt. Very easy.
But the trigger being a little short will make no difference. For with the proper hand length asjusted, the hammer can then move back forward some to the trigger as you let go of it after cocking with out moving any other parts,

Jim K
December 4, 2012, 11:47 PM
Hi, Old Fuff,

They also adjusted the SA cocking point by filing the backstrap itself where the hammer contacts it. Swayze makes a big thing out of backstrap variations in the 51 Navy, but in fact the "variations" are only where the backstraps were filed to properly time the revolvers.

Jim

Old Fuff
December 4, 2012, 11:52 PM
Well yes, you can shorten the hand, pull the hammer all of the way back, and then lower it the point where the trigger and full-cock notch come together. But frankly, that's sort of a sloppy arrangement. Also if you don't pull the hammer all of the way back, the bolt may not get to the notch because the cylinder hasn't rotated far enough.

If the bolt locks the cylinder before the hammer has fully turned to hit the backstrap (which acts a a positive stop) the shock will be transmited to the ratchet tooth, the point on the hand, the cylinder notch and the bolt. This isn't good, and it's one reason you see so many replicas with out-of-time lockwork and chewed up cylinders. At the same time you'll find well worn, 1 1/2 century old Colt's that are still fine.

towboat_er
December 5, 2012, 12:06 AM
Lots of good info here. Bookmarking this thread. Thanks

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