The Rifle Shoppe 1800 Baker Rifle Pattern Flat Ordnance Lock

In the Rifle Shoppe's description of their parts set for they above, they mention that "The tumbler has a fly so the trigger can be adjusted very light if desired". Does anyone here know what that means and how the adjustment is made? The trigger on my TRS Baker is not bad at all, but I'd like to try the adjustment. Thanks!

The' fly' is just the' detent' most US made locks have so the lock can be used by set triggers in this case they mean the trigger pull weight can be made ligther (No mechanism other that stoneing the full cock engagement Not something you need to worry about ). Unless the pull is exesessive . If it works don't fix it would sum up what Ime saying . Nice rifle.
Rudyard

Going back to the basics, the sear is the part that keeps the tumbler from turning. It does this by moving into the full cock or half cock notch.
Pulling the trigger causes the blade on the top of the trigger to push on an arm which is a part of the sear.



In the picture above, you can see the sear nose engaging the full cock notch on the tumbler.

If the sear moves downward it loses its grip on the full cock notch and the tumbler will begin to rotate counterclockwise in this picture.

With a simple trigger, the fairly heavy pressure that is being applied to the trigger by the shooters finger will tend to cause the sear to continue to move downward and away from the tumbler so, by the time the half cock notch (just to the left of the full cock notch) gets to where the end of the sear used to be the sear will be well clear of the half cock notch allowing it to go whizzing by while the hammer falls to the fired position.

Now, if it only took a very light amount of finger pressure on the trigger to release the sear from the full cock notch, the sear wouldn't move away from the rotating tumbler and there is every possibility that it will try to enter the half cock notch. If it does enter the half cock notch, everything will come to a screeching halt and the least that will happen is, the hammer will stop falling. The worst that can happen is the nose of the sear or the half cock notch or, both will be broken.

Now, enters the "fly" into the picture. (Well, not really. The lock shown doesn't have a fly in it.)
The fly is a very small part that can rotate back and forth. It is located right at the half cock notch and is inserted into the tumbler. If it is shoved toward the full cock notch by the nose of the sear while the gun is being cocked, it will expose the half cock notch so, if the shooter decides to lower the hammer while the sear is lined up with the half cock notch, the sear will enter it and the gun will be at "half cock" or in the "safe" condition.
If the shooter does not stop pulling the hammer back, the nose of the sear will ride up over the fly and end up entering the full cock notch making the gun ready to fire.

When the trigger is pulled, even with a light pressure, as long as the pressure is enough to cause the sear to disengage from the full cock notch, the tumbler will begin to rotate counterclockwise while the hammer is falling.
When the nose of the sear gets to the fly, it pushes it forward causing it to cover up the half cock notch. With the half cock notch covered, the nose of the sear can't enter it so instead, the sear pushes harder on the fly which causes the sear to raise up slightly and jump over the fly. That allows the hammer to continue to fall and fire the gun.

As Rudyard says, the fly was originally made to be used with "set triggers". The "2 trigger" guns that are on a lot of muzzleloaders.
Set triggers release the sear from the tumbler by striking the sear arm with a spring loaded blade. This causes a momentary movement of the sear causing it to disengage from the full cock notch but without the heavy finger pressure pulling the trigger, the sear almost instantly moves back against the outside of the tumbler. With a fly in the tumbler, the fly blocks off the half cock notch to prevent the sear from engaging the half cock notch.

Clear as mud? Hopefully it answers the question.

Got it! (I think.) So, the fly prevents the sear from falling into the half cock notch if the trigger is adjusted for a lighter let off, or if the trigger is pulled very slowly. By adjusted, we mean filing that's been done to the sear or tumbler, not a mechanical adjustment. Right? And, such adjustment is probably best left to someone who knows what they're doing, like the builder of my rifle, TRS. They seem to have gotten it right. My Baker's trigger seems neither light nor heavy, so it's probably best left as is.

Thanks!

Yes. Actually, there are several ways to lighten the trigger pull but if it involves messing with the sear or tumbler it should be done by experts if it is done at all.

Some of the very old CVA and JUKAR locks had a screw in the tumbler that would reduce the engagement of the sear. I'm glad they quit doing that because some people adjusted their regular trigger guns so that just a touch of the trigger would fire the gun. To say that is dangerous is an understatement.

Anyway, now you (and hopefully others) now know what a sear does and why a fly is important if set triggers are used in a gun.

Oh. While I'm at it: If the lock in a gun does have a fly in it, never try to lower the hammer directly from full cock to half cock.

The reason for this is as you recall, the fly is sticking up blocking the half cock notch off. While it is sticking up, if the hammer is lowered directly from full cock to about where the half cock notch would be, the sear can become stuck on the fly so, rather than jumping over it, it will just stop against it.
That will stop the hammer from falling and give the impression that the gun is in a safe condition. The problem is, with the sear just pushing on the fly, any jar or bump of the gun can cause the sear to jump over the fly and let the hammer fall.

The way to get around this is, if the hammer is at full cock, lower it down almost completely to a position that is below the half cock position. Then, raise the hammer back up until you hear the "click" of the sear falling into the half cock notch. Once that click is heard, the hammer can be lowered slightly to allow the sear to fully engage the half cock notch.

Zonie said:

Oh. While I'm at it: If the lock in a gun does have a fly in it, never try to lower the hammer directly from full cock to half cock....

Click to expand...

Thanks! Did not know this, and had let it become a habit to lower the hammer from full to half cock when necessary. The next time I have the lock out of the gun, I'll study the relationships of these parts. Thanks again!

This has always confused me. Is there a resource or set of images of a lock with and a lock without a fly that I can see and compare?

Nothing overly confusing about them, if it has one you can see it or feel it .If it hasn't it wont be there to see or feel .Any written reference will be to a' fly' or a' detent' . They where often taken out as being a nuisance for most practical purposes . Yet some peoples fitted them regardless like on Cape Dutch muskets or on hog rifles that only Had a full cock . I restored a 7 bore big game gun that had them new but it left such a void as to weaken the stock so it smashed in two the logic of fitting one quite pointless on the style of hunting such guns where used in. They repaired it with roof iron sheet & tacks plus Elephant er ' Parts;' to shrink over the repair and kept together out on the far Veldt . But it was broken when I got it if now its whole and servicable though there are not many Hippos or Elephants in NZ to require its use . .
Regards Rudyard

Thanks, but I need images. Perhaps this needs a Wikipedia entry?

Oldbear63 said:

This has always confused me. Is there a resource or set of images of a lock with and a lock without a fly that I can see and compare?

Click to expand...

On many locks, the fly is hidden by the tumbler bridle that covers up the area it is in so taking a picture of it installed means the bridle would have to be removed.
The tumbler bridle is the part that serves as a support bearing for the round axle or stub shaft that is on the tumbler.

Also, fly's can look quite different. The fly used in a Siler lock is a tiny casting that has a small pin cast into it. The pin allows the fly to rotate. The pin goes into a hole that is in the bottom of a small cut out pocket in the tumbler. This is located where the half cock notch is. It is impossible to assemble this kind of fly wrong.

Some L&R locks on the other hand cast the small pin into the bottom of the tumbler pocket for the fly and the fly is just a tiny oddly shaped piece of sheet metal with a hole in it for the tumbler pin to engage. This kind of fly in the L&R locks can be put into place upside down. If it is assembled that way, it won't work at all.
If your lock has one of these sheet metal fly's, be sure to take pictures of it or make a sketch of it while it is still installed in the tumbler. Refer to the pictures before reassembling the fly into the tumbler. Also, before installing the lock mainspring, test the fly by bringing the hammer to full cock, releasing the sear and, while holding the nose of the sear against the body of the tumbler, lower the hammer with your thumb. It should lower completely as the sear jumps over the fly.
If the sear tries to fall into the half cock notch, the fly is installed wrong so take it out, turn it over and reinstall it. Then, test the hammer to make sure it will fall all the way from full cock to the fired position. If it does, now you can complete the assembly of the lock.

I edited this post to show a few pictures I found on the web.
This is a TC Hawken tumbler. You can see the hole for the fly


This picture shows the parts of the lock.


The fly is letter I.