Lock help

[Davemuzz]

I have an L&R (I think it's an L&R) lock with an "issue."  The problem is that I cannot fully tighten (and Im not doing a gorilla torque) the sear\bridal screw without the sear arm becoming hard to move.

Now, I've gingerly filed the sear arm along with polishing the arm, and the side plate it is against. This has helped somewhat, but my concern is I don't want to remove "to much" material from the sear arm. But perhaps I'm being to cautious.

BTW, the book "The Gunsmith of Grenville County" doesn't address this specific issue of the sear\bridal screw.

Thanks much

Dave

[G_T]

I've had to alter L&R locks before for lack of square. Check to see if the bridal is parallel with the lock plate and that the holes actually line up correctly. There may even be enough slop that you need to line them up while tightening the other bridle screws.

That's where I'd look first. Also, tighten that sear screw last and don't over-do it.

You should check that the bridle is parallel with the plate without the other innards present. Add parts, one at a time, and make sure they move correctly - easily, without the springs being present. I've had to file to alter the angle of the bridle on an L&R percussion lock last winter for a friend. It was visibly off and caused the same problem you mentioned. There were other problems that needed solving though. Seeing that the lock works smoothly without the springs will help. Spring tension can mask the feel of a little binding on an otherwise smooth and lubricated lock. I had to remove some burs and do a bit more once the bridle was parallel enough.

IMHO of course; there are those here with orders of magnitude more experience than I!

Gerald

[rich pierce]

Usually this is simply a case of the threading on the screws covering more of the shank than needed. Not a big deal. Just tighten to where things are secure and still move freely.

[Ky-Flinter]

Why don't the lock makers provide a sear screw with the appropriate shank length, so the screw can be tightened securely, but still allow the sear to pivot freely?

-Ron

[Blacksmoke]

Hi Dave,  I always make a new sear screw which has a shank long enough so as not to pinch the sear against the bridle and the lock plate. If you do not have a small lathe use your drill press like I do and turn the screw using a file or do a drawing and take it to a small machine shop and get them to turn it.   Hugh Toenjes

[EC121]

Being lazy, I have just ground a bit off the bridle in the area around the screw head  to let the screw bottom out without pinching the sear.

[smart dog]

Hi,
The problem likely is that the sear screw has too much thread. The simple solution is to tighten the screw until the sear binds and back it off slightly.  The best fix is to make a new screw with just enough threads to tighten on the plate but not bind the sear. This is just an example of poor assembly by the maker. One thing to check before fooling with the screw and sear is if the bridle is parallel with the plate. Attach it to the plate with the front screw and without the tumbler in place, and check that it is parallel.  These are the reasons why some locks cost a little less up front but end up costing a lot more in shop time later.

dave

[Davemuzz]

Thank you Gentlemen for your input. I will "have at it" later today.

Dave

[Bob Roller]

My approach to this is a sear pivot screw of .109 in a .110 hole with a stub thread
and the shank buried into the lock plate.This prevents binding and keeps the thrust
of the mainspring at full cock from becoming a problem.
Production work is just THAT ,production and quality control frequently can be sacrificed
for expediency..

Bob Roller

[Bob Roller]

Hi Dave,  I always make a new sear screw which has a shank long enough so as not to pinch the sear against the bridle and the lock plate. If you do not have a small lathe use your drill press like I do and turn the screw using a file or do a drawing and take it to a small machine shop and get them to turn it.   Hugh Toenjes

Finding a machine shop,small or large to do a single job like this can be very costly.
A drill press has POOR orientation.IF you have an old American made bench grinder
it may have a 1/2x20 right hand thread on the right side. Buy a Jacobs type chuck
with the 1/2x20 thread and use it as a nut on the grinder and the job will go easier
and safer. I have an old Atlas 618 lathe bought new in 1964 that is dedicated to screws
and other special jobs.

Bob Roller

[Long John]

Dave,

You have received advice from folks that are far better gunsmiths than I am.  My solution would be to strip the lock down, lay the lock plate on an anvil out-side face up and peen the hole for the sear screw down a little to upset the threads enough to limit the depth the screw can go.  Re-assemble lock and see how it works.  Another solution is to remove the sear screw, lay it flat on the anvil and carefully upset the last couple of threads where the threads end on the screw shank.  This will also prevent the screw from going too deep into the lock before the threads bind-up and provide the friction to hold it in place.

But, like I said, the gunsmiths that are better than I am would make a new screw.

Best regards,

JMC
John Cholin

[L. Akers]

Being lazy, I have just ground a bit off the bridle in the area around the screw head  to let the screw bottom out without pinching the sear.

I think you are smart--not lazy.  This is the method I use to I correct this problem on any lock as L&R is not the only lockmaker to have this issue.  I would caution  that material removal should be from the outer surface under the screwhead and not from the inside of the bridal.

[smart dog]

Hi,
If the bridle is hardened and tempered as it should be, you either have to anneal the bridle or revert to stones and diamond files.

dave

[D. Taylor Sapergia]

I have put up with this problem for a long time, and here's how I remedy it...
As already stated, making a new screw is the best fix, and it's easy if you have a lathe. So I bought a $3000 lathe so I can make fifty cent parts.
Another method is to put the crew into the chuck of the drill press, and with a safe edged file, reduce the thickness of the head of the screw FROM THE INSIDE of the head.  It does not take a lot of material removal to make all the difference in bringing the screw down tightly against the end of its threads in the plate.
And last, countersink the hole in the bridle t let the screw go into the bridle until it bottoms tightly  against the end of its threads.  You can go half way through the bridle without causing any issues, but usually don't have to.  After relieving the hole for the head a bit, make a bottoming drill to match the cheese head of the screw.  But I prefer to make a new screw.
Before I bought my lathe, I too used my drill press, or simply clamped my electric hand drill in my machinist's vise, and thus made a poor man's lathe.  The drill press works better 'cause you can use the table to support the file on edge.  Actually, use two files:  one reversed, so that you take metal off both sides of the revolving steel at the same time.  This helps avoid making 'out of round' screw shanks and heads.
I know what you're thinking...I paid good money and still have work to do on my lock.  My reply:  make a lock from scratch to see what a value you are getting in a commercial one.  I concede that some locks are better than others.  But don't be put off because you have to tinker...tinkering is good.

[Davemuzz]

Well, again I thank all of you for your input. I now have the sear arm working as it should with no bind, and the screw is tight. What I did was to remove a small amount of material on the sear arm, where it was binding against the lock plate. In addition, I took about 5-thousands off the bridal (inside), but only where the sear screw hole is, and out to the edge.

Doing both gave enough freedom for the sear arm to move where it needs to move, and trigger pull is much better!!

PS....while I had the sear\bridal screw out I also chucked it in my drill press and polished it up with some leather coated with strop paste. That may have assisted the trigger pull as well.

Again, Thanks!

[jerrywh]

 Like Taylor. I bought a $3000.00 Lathe to make 50 cent parts. But the 50 cent parts are for $30,000.00 guns. Or More. Much more. HEEEEE Heeee