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CAS TOPICS => Gunsmithing => Topic started by: Oldgold on May 25, 2020, 07:00:14 AM

Title: Pietta 1851 Navy question???
Post by: Oldgold on May 25, 2020, 07:00:14 AM
I obtained the Navy without cylinder or internals. Ordered all the internals and began the arduous trial and fit. After a month off and on, seems to be one small problem. The timing is great, except when I put the cylinder and barrel back on. Then it will not come to full cock. I can hold the trigger down and everything works like when you fan a pistol. (I don’t). My guess is the hand is too long. I have shortened it a few thousand s, but before I go down that rabbit hole, I wanted to ask the experts. Any thoughts?
Title: Re: Pietta 1851 Navy question???
Post by: 45 Dragoon on May 25, 2020, 11:08:19 AM
    First of all .  .  .  WOW!!  "Timing is great"  .  .  .  .  it just doesn't work with the cylinder and barrel installed!!! Bummer .  .  . 

  Ok, timing made easy or Timing 101.

1- with barrel and cylinder installed, the bolt must lock the cylinder when the hammer reaches full cock. This means that no matter how late the bolt drops (hits the cylinder after half cock is reached), the hand MUST be adjusted to "carry up" the next chamber to battery and the cylinder lock at the same time the hammer reaches full cock. This is the "length of cycle". Even if you're on a " hunt" and have to start at half cock (because the bolt won't unlock the cylinder from hammer down), the end of cycle must be reached. That is simultaneous cyl lockup/full cock reached .  .  . sounds like one click.
  When you achieve that,  you can  move to step 2.

2- now you can set the "bolt drop" (timing. See, this is the "timing" that folks talk about but it is impossible to know the condition of the timing if you don't know where the bolt drop happens on the cylinder).  The bolt should hit in the " approach " (the cutaway that leads to the locking notch on the cylinder). You do this by removing material at the very end of the left bolt arm (the one that rides the hammer cam).  There is a lot of material on a new part but still go slowly (it's hard to put metal back on). Again, if you have to start at half cock (for the same reason as above) start there. If you can start the cycle with the hammer at rest (because the fitting of the hand to achieve step 1 allows you to) that's great!!
   So, if you are successful, you should at least have bolt drop in the "approach"  and simultaneous cyl lockup/full cock. Now you have "great timing".

3-  If you can cycle the action from "hammer down", that's excellent. If you can't, you may need to increase the cut for the cam to allow " bolt reset". "Reset" has to happen before you can cycle the action again. It means the left arm has to be back on top of the cam so the cam can push the arm up so the bolt head will move down and unlock the cylinder. If you listen to the two clicks as the hammer goes down to rest, the first one is the hand engaging the next ratchet tooth on the cyl, the second one is the bolt arm snapping back on top of the cam. The hammer face should be flush (or very close to flush) with the recoil shield. Otherwise, you may not be able to cycle the hammer back if you let it down on a live cap or worse, a loaded chamber.

  Now, what I've described to you is very easy to see when you view the action with the trigger guard off. You can see what "reset" is as well as bolt "pickup" which is when the cam starts moving the bolt arm to unlock the cyl.

  It may seem a little complicated and it is if you've never done it before. Just go slow, know what you are looking for, watch often.

Title: Re: Pietta 1851 Navy question???
Post by: Oldgold on May 25, 2020, 11:18:20 AM
Thanks for the quick reply. Got a fishing trip starting tomorrow. Will jump on it next weekend and let you know.
Title: Re: Pietta 1851 Navy question???
Post by: Oldgold on March 31, 2021, 05:02:46 AM
An update for future reference if someone needs it.
The hand was way too long. Had to thin slightly and shorten a bunch. It works great now. Thanks for the help. Fussed with this thing off and on for a while.
Title: Re: Pietta 1851 Navy question???
Post by: RRio on July 21, 2021, 09:37:10 AM
Will this help?