Uberti 1873 over rotation/ throw by new hammers

[Wild45]

Hello all. Hoping the experts in here can guide me through this issue or let me know if this is a job for a gunsmith. 

 

I have a pair of Uberti Cattleman 1873’s or technically Cimmaron Thunderers. I just switched the original hammers with new runnin iron hammers from Taylor. The only hammers available from them now we’re the new safety style with a retractable firing pin. I replaced the hammers as well as the triggers to work with them. 

 

On function ion test everything is working fine when cocking hammer as slower speeds. The cylinder bolt engages just at the beginning of the groove before the notch and at full cock everything locks into place. 

 

If cocking fast however the bolt does not catch the notch and cylinder over spins landing somewhere in the middle, or in some cases will spin right to the next notch and lock up. 

 

Replacing the original hammer fixes the problem. However On function test with both hammers the bolt appears to engage the cylinder at the exact same time, but will only over rotate with the new runnin iron hammers. 

 

I have ruled out out the bolt spring being the issue. 

 

Does anyone have any clue what could be causing this suttle but serious issue ? 

[Trailrider #896]

I am NOT an expert on the subject, but it sounds like the location or shape of the cam surface on the new hammers are different from the originals.  The bolt is cammed down by the projection on the side of the hammer.  As the hammer is cocked the cam causes the bolt legs to pull the bolt down so the cylinder can rotate.  At a certain point in the cycle, the cam slims down until the bolt legs slip past it, releasing the bolt to drop into the notches in the cylinder. It takes a few milliseconds for the bolt to pivot around its pin.  The cam on the new hammers obviously are delaying release of the bolt long enough for the cylinder to rotate past the lockup point.  This is called "timing".  The cams on the new hammers will have to be CAREFULLY stoned to correct the timing.  This is usually a job for a competent single-action gunsmith.

[Garrison Joe, SASS #60708]

2 hours ago, Wild45 said:

I have ruled out out the bolt spring being the issue. 

 

What observation causes you to believe that?  

If you could find a stronger bolt spring, I'd try that first and possibly not have to try to fix some complex timing issue with the hammers.

 

Good luck, GJ

[45 Dragoon]

It's probably the difference in the hand location between the two hammers. Hammers and triggers aren't "drop in" parts .  .  .  oh, they may function .  .  . kinda. 

 

  In Wild 45's case, the hand is probably still putting pressure on the ratchet at lock-up. That will cause throw-by. The fix would be to dress the top of the hand some. This may cause the original hammer to not allow complete carry-up (assuming your using the same hand on both hammers).

  You can verify this by checking the cylinder rotational play with hammer at rest and at full cock. If there's no play at full cock, hand is too long.

 

Mike

[Old Man Graybeard]

The hammers and triggers...not sure about the hands...are different on the new three click compared to the older four click revolvers. The newer ones have a curved piece on the trigger that operates the actuator rod that goes up through the hammer to hold the firing pin out. Just replacing the hammer without all he rest may be the problem.

[Cholla Bob]

19 hours ago, Trailrider #896 said:

I am NOT an expert on the subject, but it sounds like the location or shape of the cam surface on the new hammers are different from the originals.  The bolt is cammed down by the projection on the side of the hammer.  As the hammer is cocked the cam causes the bolt legs to pull the bolt down so the cylinder can rotate.  At a certain point in the cycle, the cam slims down until the bolt legs slip past it, releasing the bolt to drop into the notches in the cylinder. It takes a few milliseconds for the bolt to pivot around its pin.  The cam on the new hammers obviously are delaying release of the bolt long enough for the cylinder to rotate past the lockup point.  This is called "timing".  The cams on the new hammers will have to be CAREFULLY stoned to correct the timing.  This is usually a job for a competent single-action gunsmith.

This is the problem that I have run into when swapping hammers on revolvers, each one is fit individually.  So fitting takes time (modify, assemble, test, disassemble, repeat) There is a reason that revolvers are more expensive than pistols.

[45 Dragoon]

20 hours ago, Trailrider #896 said:

 The cams on the new hammers will have to be CAREFULLY stoned to correct the timing.  This is usually a job for a competent single-action gunsmith.

 

This is a little alarming, I'm sure this was learned from watching a YouTube video  (he always tells you to get extra parts .  .  . and he ain't kiddin!!! (You're gonna need um!!!)).  You don't adjust timing by filing on the cam, you file or sand on the left bolt arm.  By the way, I'm not admonishing Trailrider per se, those videos have been watched (and followed) by too many people!! YouTube isn't the best place to learn how to fix your revolver (especially when they can't even name the parts correctly half the time!!).  Even when cams were a separate part, you don't set the bolt drop by filing away on the cam. Today, the cam is integral with the hammer so .  .  .  

  You can " adjust" the height of the cam, polish the cam but don't diminish the circumference of the cam to adjust timing. Replacing a bolt is cheaper than a hammer. The left bolt arm is supposed to fall off the front of the cam as it is being pulled rearward (not slide off the side as the video suggests). Anyway, just thought I'd share that little bit .  .  . maybe it'll save a cam or two.

 

Mike

[Doc Flimshaw Sass# 73310]

One word..... "Gunsmith"

[Trailrider #896]

1 hour ago, Doc Flimshaw Sass# 73310 said:

One word..... "Gunsmith"

Yup! As I mentioned, I do NOT do such work myself.  I find a competent 'smith who knows how to time single-action revolvers.

[Cypress Sam, SASS #10915]

11 hours ago, 45 Dragoon said:

It's probably the difference in the hand location between the two hammers. Hammers and triggers aren't "drop in" parts .  .  .  oh, they may function .  .  . kinda. 

 

  In Wild 45's case, the hand is probably still putting pressure on the ratchet at lock-up. That will cause throw-by. The fix would be to dress the top of the hand some. This may cause the original hammer to not allow complete carry-up (assuming your using the same hand on both hammers).

  You can verify this by checking the cylinder rotational play with hammer at rest and at full cock. If there's no play at full cock, hand is too long.

 

Mike

The lower shelf on the hand, not the top, is what is in contact with the ratchet at lockup (full cock).  The top of the hand engages the ratchet and begins the cylinder rotation which is continued by the lower shelf as the top slips off the ratchet.  The lower shelf continues the rotation around to lockup.

 

The bolt should drop just when it will engage the lead on the cylinder and can be adjusted as noted by 45 Dragoon above.

 

The earlier Colt cap and ball revolvers like the Walkers, Dragoon’s and 1860 Armies (maybe other C & B models as well) had a hand that had no lower shelf.  On those models the top of the hand rotated the cylinder all the way to lockup.  The 1873 Colt action has a two-step hand though.

 

If your guns timing is proper when cocked slowly but not when operated fast, and your bolt spring is strong enough, then you might have excess friction somewhere that is causing drag and slowing the bolt drop.  A more likely cause though is a combination of LATE bolt drop and a very light hand spring.  The friction of the hand on the ratchet retards the cylinder rotation, preventing the cylinder from overspinning (outrunning the hand) thus having the cylinder notch already past battery when the bolt drops.  (On guns with this problem, you can usually duplicate the situation by starting a cocking motion, quickly stopping immediately after cylinder rotation begins letting rotational inertia allow the cylinder to rotate past battery.)

 

The fix is to either adjust the timing so the bolt will drop sooner or increase rotational friction with a stronger hand spring or both.

[45 Dragoon]

Cypress Sam, you're absolutely correct!! I pretty much live in the "single fingered hand" world!! Glad you pointed that out! I'd be in trouble if he shortened the top hand ( like i said above, careful who you listen to!! Lol!!).

  You're right about the hand slowing the cylinder down for lockup too! That's why i use a stouter spring for my coil/coil conversions.  Throw-by is also indicative of a mal-adjusted or cracked flat hand spring. 

 

Mike

[The Original Lumpy Gritz]

Bottom ledge of the 'hand' needs to be fitted to the cyl ratchet, because of the new hammers.

I suggest you order 2 new hands and leave the others with the old hammers.

OLG 

[Butch McGie, SASS#71758]

Check with Jerrad at Long Hunter Shooting Supply.  He has this problem figured out.  My open tops shoot like Rugers now.