Little Things - Cylinder Movement @ Firing Position

[Johnm1]

I must have too much time on my hands. I sit and observe and see things I don’t understand. Below is a link to a slow motion video of my 1860 Army. First off, it is a large file and takes probably 20-30 seconds to download. I made it as small as possible and still show the phenomenon.

Just as the hammer approaches the firing position there is the tiniest amount of movement of the cylinder. And I mean really tiny. But I don’t really understand what causes the movement. There is a tiny bit of wiggle in the cylinder with the hammer in the fully cocked position. Much like a modern S&W double action revolver. I sense that as normal and not something unexpected. When the movement occurs the hammer is almost all the way forward and the hand has dropped almost completely removing one of the two points of contact: The two points being the Cylinder Bolt, which is fully in its notch, and the hand on the ratchet teeth. But the hand has dropped and is no longer in contact with the ratchet teeth. It occurs on all cylinders and is consistent on all cylinders.

But what actually makes the cylinder move? Maybe the hammer pressing on the nipples?

Here is the link to the video

https://photos.app.goo.gl/afdM4xj8pwermC5bA

Again I apologize for the size of the file.

 

[45CalPal]

Sorry, i have not seen the file, but Metal parts aginst metal parts in general are prone to create a "wear" pattern with age and use. No 2 guns alike will create the same pattern. Sounds like you have some slight wear on some parts allowing movement. basically the tolerances are not as tight as they once were.

 

[hawg]

The video is too blurry to see any movement but when the hammer contacts the nipple there will be forward movement of the cylinder. It's not a good idea to dry fire a C&B revolver.

 

[gobsauce]

Maybe the hand being retracted into the frame with the movement of the hammer?

 

[Jackrabbit1957]

Most likely spring pressure from the hand spring plus a small amount of wear on the bolt slots.

 

[noelf2]

The video is too blurry to see any movement but when the hammer contacts the nipple there will be forward movement of the cylinder. It's not a good idea to dry fire a C&B revolver.

He didn't dry fire. Thumb was on the hammer. Probably too blurry to see, but it's a pretty clear video for me.

OP: I would be curious to see the cylinder chamber to barrel alignment in full cock and in full hammer drop. One or the other is going to be a bit out of center. You can tell by shining a light down the muzzle and looking for a bit of cylinder face shining back at you, like a crescent moon.

 

[Johnm1]

Maybe the hand being retracted into the frame with the movement of the hammer?

Most likely spring pressure from the hand spring plus a small amount of wear on the bolt slots.

He didn't dry fire. Thumb was on the hammer. Probably too blurry to see, but it's a pretty clear video for me.

OP: I would be curious to see the cylinder chamber to barrel alignment in full cock and in full hammer drop. One or the other is going to be a bit out of center. You can tell by shining a light down the muzzle and looking for a bit of cylinder face shining back at you, like a crescent moon.

Odd that it is blurry for you @hawg. When I edited the video it was in postage stamp format and that is too small to see the movement. If viewed full screen, even on my phone it is clear and the movement is obvious.

The hammer face hasn't passed the breach face when the movement occurs. So I think we can eliminate contact with the nipple. The visible movement occurs just as the trigger resets.

Looking down the bore the alignment starts out correct with the hammer at full cock. But as the hammer is slowly released I can see the cylinder being slowly pulled backwards I assume as the hand travels down the face of the cylinder. When the trigger reaches reset the cylinder moves back forward to the aligned position. Or nearly so.

During all of this.I can tell the bolt remains within the slot in the cylinder and the amount of movement is limited to the clearance between the bolt and the cylinder slots.

I'm supposing that the hand is pulling the cylinder backwards as it travels downward. The backwards movement is spread over the time it takes the hand to go from full up to full down. I can only see that movement while looking down the barrel with a light as @noelf2 suggested.

So at full cock the cylinders are in alignment, the cylinder is pulled backwards slightly out of alignment I'm assuming by the hand as it is traveling downward and as the trigger resets the cylinder rotates back to the aligned position. What force rotates the cylinder back forward to the aligned position eludes me I'm supposing on all of this.

FYI - I never considered this a safety issue and wasn't concerned it was even a performance issue though I suppose it could be a performance issue. I knew that the amount of movement was limited to the clearances between the bolt and the cylinder notches.

 

[mcb]

Most likely spring pressure from the hand spring plus a small amount of wear on the bolt slots.

I think this is probably it. Just before the hammer would contact the nipple the hand is snapping over the edge and into next notch in the star. This change in contact point between the star and hand is causing the cylinder to move slightly within the play/tolerances of the cylinder stop, in the frame and in the cylinder stop notches. It does not look like it enough to cause issue IMHO.

 

[Johnm1]

change in contact point between the star and hand is causing the cylinder to move slightly within the play/tolerances of the cylinder stop

Ah, good point. I notice that what I thought was the trigger reset click that I heard as the movement happens isn't there when the cylinder is removed. So it isn't the trigger reset that causes the forward movement but the hand moving into the next notch.

And yes, I never figured the movement was enough to cause an issue.

Way too much time thinking about this, but I think we now know what causes the forward movement. Thanks all.

 

[entropy]

But I don’t really understand what causes the movement.

The scraping of the hand against the the star, as well as the trigger drawing along the trigger and bolt spring; as the hand slides down the star, it creates movement, and as the trigger moves across the spring, it does also.

The slight movement of the cylinder is because there is tolerance in the size of the cylinder stop notches. It's not a precision target pistol, if Colt was even capable of such in 1860.

Mystery solved.

 

[hawg]

Odd that it is blurry for you @hawg. When I edited the video it was in postage stamp format and that is too small to see the movement. If viewed full screen, even on my phone it is clear and the movement is obvious.

I watched it on my computer. I don't use my phone for forums.

 

[entropy]

It is blurry on a computer screen, and clear on a phone. Worked for me either way.

 

[45 Dragoon]

Well, there is no "trigger reset". There is a " trigger return " which happens when moving your finger forward and off the trigger (no sound). The two clicks heard as the hammer returns to down position is the hand selecting the next ratchet tooth (1st click) and "bolt reset" (2nd click) as the left arm resets on top of the cam.

A bolt block will clear up most all of any bolt slop, taking the bolt window (hole in the frame) excess out of the equation.

Mike

 

[44 Dave]

Mike's bolt block suggestion sounds good. All you need is a piece of key stock and a file and patience.

 

[Johnm1]

Mike's bolt block suggestion sounds good. All you need is a piece of key stock and a file and patience.

It actually does have a bolt block that I made at the suggestion of @Jackrabbit1957 . I hand machined it (oxymoron) and I'll look at it again tonight to see if I can 'snug' it up a bit. I bet I can.

Well, there is no "trigger reset". There is a " trigger return "

Good point. Words have meaning and I am guilty of using terms incorrectly. Like slug the 'bore' when we are really trying to measure the grooves.

 

[44 Dave]

You can tighten a bolt block a bit by upsetting the back side , use a punch in a number of places and then true it up again.

 

[Johnm1]

You can tighten a bolt block a bit by upsetting the back side , use a punch in a number of places and then true it up again.

I didn't understand what the bolt block did when I made it and I made it out of aluminum. I'll give a go at making another out of steel and now think about where I want the bolt to be in its opening. I don't think it will make a difference in what we have been discussing (maybe it will) but it really needs to be done right and out of steel.

 

[woodnbow]

I must have too much time on my hands. I sit and observe and see things I don’t understand. Below is a link to a slow motion video of my 1860 Army. First off, it is a large file and takes probably 20-30 seconds to download. I made it as small as possible and still show the phenomenon.

Just as the hammer approaches the firing position there is the tiniest amount of movement of the cylinder. And I mean really tiny. But I don’t really understand what causes the movement. There is a tiny bit of wiggle in the cylinder with the hammer in the fully cocked position. Much like a modern S&W double action revolver. I sense that as normal and not something unexpected. When the movement occurs the hammer is almost all the way forward and the hand has dropped almost completely removing one of the two points of contact: The two points being the Cylinder Bolt, which is fully in its notch, and the hand on the ratchet teeth. But the hand has dropped and is no longer in contact with the ratchet teeth. It occurs on all cylinders and is consistent on all cylinders.

But what actually makes the cylinder move? Maybe the hammer pressing on the nipples?

Here is the link to the video

https://photos.app.goo.gl/afdM4xj8pwermC5bA

Again I apologize for the size of the file.

Looks like the bolt is resetting at that point in time.

Edit: I should have read the thread. Asked and answered …

 

[45CalPal]

Id say if its rotation, you may be ok. But if its lateral movement, then something is deffinatly worn and allowing abnormal movement.
If in the half cocked position this should free the movement, then you grab the cylinder and slightly wiggle it, does it have any movemnet?

 

[Acorn Mush]

A bolt block will clear up most all of any bolt slop, taking the bolt window (hole in the frame) excess out of the equation.

Mike

I recall reading something about bolt blocks a long time back but could never find any details as to function and fabrication. Is a bolt block something that can be made by someone with a modicum of skill with files? Are there any pictures available? Perhaps a link to a previous post somewhere?
Thanks in advance for any info you might be able to provide.

 

[44 Dave]

Bolt block, in a SAA

 

[gobsauce]

I recall reading something about bolt blocks a long time back but could never find any details as to function and fabrication. Is a bolt block something that can be made by someone with a modicum of skill with files? Are there any pictures available? Perhaps a link to a previous post somewhere?
Thanks in advance for any info you might be able to provide.

A bolt block basically holds the bolt in place. It makes it so it only moves the way it should. @44 Dave 's picture is perfect.

 

[Acorn Mush]

Bolt block, in a SAAView attachment 1053430 View attachment 1053431

A bolt block basically holds the bolt in place. It makes it so it only moves the way it should. @44 Dave 's picture is perfect.

Thank you both very much!

 

[Johnm1]

Even though this wasn't an issue I'm glad we had this discussion. I learned a bit. Thanks all for participating.

 

[woodnbow]

Even though this wasn't an issue I'm glad we had this discussion. I learned a bit. Thanks all for participating.

There are some really smart people around here…