A "fly" in the tumbler

[Davemuzz]

When I built my Leman I began with the lock. I disassembled it, filed, stoned, sanded all parts to a point where I thought everything not only looked good, but worked well. I "tested" it just in my hand and there didn't seem to be any difficulty in trigger pull "poundage."

Fast forward to completion, and I found the trigger pull had a "spongy" feel to it just before the sear released. At first I though "break in."  Now, remember I have trigger experience with a total of 2 builds. Far from expert.

So, after a few range trips, the trigger was not better. Just the same. So, out comes the lock and apart comes the lock. In examining the lock where all parts meet, I see a dimple, and a scrape mark on the Bridle....and it happens to match the tiny fly stud in the tumbler (dimple) and the scrap marks line right up with the fly. (L&R)

So, a small file followed by 600 grit....several times to keep testing....and done!!

Now the trigger pull is absolutely delightful!! Half cock works just like it should, and full cock does the same.

It's always attention to detail......as I continue to learn!!

Dave

[45-110]

i have found the "as cast" fly pivot stud to frequently be poorly formed almost to the point of drilling out the thing and putting in a tool steel pivot pin. also the surrounding rough cast fly pocket requires a bunch of work to de-burr and polish. never really understood attempting to achieve this level of precision by the casting process on such small pc's. a cast pocket with out the integral post would be so much easier to refine.
best
kw

[Davemuzz]

I found the oddest thing about this was, the fly AND the stud had actually been filed or sanded down in.....what I can only guess.....an attempt to have the sear work properly. Yeah.....not so much.

I polished the tiny fly up as best as I could, and then took my jeweler's round file and de-burred the small fly hole. Since that made the fly move freely, I didn't attempt to clean up the cast section where the fly resides. To easy (IMHO) to simply screw it up.

[Bob Roller]

I found the oddest thing about this was, the fly AND the stud had actually been filed or sanded down in.....what I can only guess.....an attempt to have the sear work properly. Yeah.....not so much.

I polished the tiny fly up as best as I could, and then took my jeweler's round file and de-burred the small fly hole. Since that made the fly move freely, I didn't attempt to clean up the cast section where the fly resides. To easy (IMHO) to simply screw it up.

That is a very unusual method of installing a fly and every tumbler must be inspected to
see if that little stud is in place. I have never seen this on antique locks but then ANY thing
is possible.My locks are not done this way.

Bob Roller

[varsity07840]

It’s easy to put the fly backwards in the tumbler with that post thing.

[Davemuzz]

It’s easy to put the fly backwards in the tumbler with that post thing.

You raise a very good point. When I began the whole build project I (of course) disassembled the lock. I placed the tiny fly along with the other parts in a clear heavy plastic bag. Fast forward to 5 months later when I'm completing the project, and then assembling the lock.....and I get to the fly and ask myself....which way? 

I suppose it's obvious when you do a lot of builds, but for me I assembled the tumbler, sear and bridle and put the fly in both ways to observe. If you have it in wrong it could cause the lock to catch on half-cock upon trigger pull. (I didn't test that....but I think that's a likely outcome) Not what you want.    But working the action without the mainspring in, will eventually bring you to the right conclusion. At least that worked for me.

Dave

[D. Taylor Sapergia]

L & R's little fly with the hole for the peg, has two angle flats along the working bottom edge.  The short angle is forward, and the long flat is toward the rear.  These are stamped out of steel sheet, and so have a rounded side and a sort of hollow side.  The rounded side is up.
Advice like this is fine, but not as good as learning the hard way.

[Pete G.]

Learning the hard way can be expensive

[Daryl]

I usually lost a lot of blood as I learn to use cutting tools.
Now, I mainly use blunt objects & let those with skill do the
work with cutting instruments.

[Davemuzz]

These are stamped out of steel sheet, and so have a rounded side and a sort of hollow side.  The rounded side is up.

This rounded side of the fly must have been a little to rounded as the lock tuner filed that side down some. That, along with the peg. He\She just didn't file the peg down enough. That and I relived some metal on the bridle where the peg came in contact.

[D. Taylor Sapergia]

They are just thick enough as issued.  If you file them down, or stone them flat, they become too thin, and do not work as well, sometimes jumping off the peg.