A lock conundrum

[Steeltrap]

So, I buit this rifle over a year ago. I decided that the very small gap between the bolster and barrel needed to be tight (or tighter) against each other. Ok...no big deal.

So, I snugged it up, then with candle soot, checked for any contact points. I've done that about a dozen times and can't find any. The lock spring appears to have enough clearance that it's not being impaired against the wood or the barrel.

Now...prior to my moving the lock in perhaps the .004" that I just didn't like, the lock functioned fine.

But now, when I tighten the screws (even just the top screw alone) and pull the trigger, the pan will not completely open. If I remove the lock from the mortise, the pan will open every time. 

Now, this has been driving me a bit nuts for over a week. I pick it up and put it back down so I can always look at it with fresh eyes.

Today, I noticed something. When the lock is installed, and I cock the hammer, if I hold the hammer and slowly let it down, there is a discernible "click" and I feel a definite "rub" or "bump" when the hammer is coming down at half cock.

Now, I've done this same thing with the lock removed and that click or bump isn't there. I've manipulated the fly in both directions prior to slowly letting the hammer down (out of the mortise of course...can't do it when the lock is in) and I don't get the click or bump.

And I've also checked for the pan that it's not rubbing against the barrel. And I don't believe it's the pan "snapping back" quickly as it would....I think....do that inside or outside the stock.

I have no markings inside the lock mortise from spring.... back to sear lever.

Any thoughts?

[bluenoser]

Sounds like the end of your sear arm might be bottoming out now that you have lowered the lock.  Could also be the bridle, sear, or tumbler bottoming out, but my money is on the sear arm.

[Steeltrap]

Thanks Bluenose. I double checked that. I used my mic to check the depth of the hole and it was close. So I drilled it just a bit deeper, cleaned it out really well, but I'm getting the same result. I also removed just a bit more wood where the hammer gets close to the stock.

No avail.

I can pull the lock out and it works great......install it with one or even two screws....and it simply will not produce enough energy to completely open that pan cover.

I feel for sure something is rubbing\binding and the hammer is losing energy prior to impact. I'm using my magnification headset to scrutinize the mortise....but to no avail.

The pan is not hitting the barrel. I know this because it's a hook\breech setup and I have the barrel completely out when working on this issue.

I also know it's not the trigger. As I have the trigger completely removed and I'm setting off the sear bar by touching it with a screwdriver.

I set it aside for a time as I'll look later.

[Dale Halterman]

Is the hammer rubbing the stock before it comes to rest on the edge of the lock plate?

Dale H

[Steeltrap]

I just figured it out.

I went back to my little shop and installed the lock again. Then I flipped the rifle over to set off the sear bar with a screwdriver. When the lock went off, the pan stayed open.....but my index finger hurt. My finger was hit by the pan when it opened.

So, I held my thumb out to where the pan would be completely open.....set the lock and (after installing the trigger) pulled the trigger. My thumb got hit by the pan....and it remained open.

Now, I've read where such things occur and the pan opens and closes so fast, it cannot be seen by the human eye. High speed video apparently can catch it....or what I did by placing an object (my thumb) to where the opening pan would hit my thumb before it had a chance to rebound back.

My "thumb" method works every time.

So.....I recall reading about this, but I don't recall what the "fix" is. Do I need to replace the frizzen spring?

[Bob Roller]

That click could be the sear crossing the fly if the lock has one and the camming action created might cause the sear arm to snag the hole in the stock where it goes.Guess work only.
Bob Roller

[sbowman]

 Try playing around with the flint before you mess with the spring. I had that problem with a Davis lock. I fixed it by moving the flint in the cock. I'm  pretty sure I moved it out so that it would strike the frizzen sooner taking away some of the momentum  but don't recall for sure. also try flint bevel up and bevel down.

Steve

[Steeltrap]

This is a small lock. An L&R Manton. I am using 5/8" flints with the bevel down. The lock can't be bevel up or the top jaw screw will hit the top of the frizzen.

My flint is almost touching the frizzen and the flint may be able to move back more.....but I'd have to cut out the leather. The leather is pretty thin now.

The only reason I think the lock functioned properly when just held in my hand is, the energy "moves" the entire lock...(my hand is not as solid as wood\metal).  When the lock is in the stock, all the energy is released into the frizzen.

[sbowman]

 "The only reason I think the lock functioned properly when just held in my hand is, the energy "moves" the entire lock...(my hand is not as solid as wood\metal).  When the lock is in the stock, all the energy is released into the frizzen."

I can understand that. May just have to mess with the spring after all.

Steve

[yip]

  A PICTURE IS A GOOD IDEA.

[Steeltrap]

Pictures. Hmmmm.....well, I took a slow motion video on my iPhone. Then I stopped the video and took a screenshot of the three "steps" of what the lock is doing. I will attempt to explain:


This first pic is the initial strike of the frizzen. You can see the initial spark...but the frizzen is moving so fast the photo\video doesn't pick it up. But you can see the frizzen finial and the spring not yet compressed.


Now this next image is interesting. You can see the light "grey" of the frizzen and the finial moving all the way forward....and it's grey as it likely picked up the movement back.


And this third picture is what occurs when it's done cycling. This one shows the very end of the movement. The frizzen has now snapped back against the flint and that's how it ends up.

[Steeltrap]

Just a follow up. I called L&R and they stated it was the frizzen spring that is likely not strong enough to hold the frizzen open.

I am sending the lock back to have them install a spring of the right strength.

[Steeltrap]

Here's the slow motion video. You may have to watch it a few times to see the bounce.