Author Topic: Lock tuning and polishing  (Read 1191 times)

Offline WonkyEye

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Lock tuning and polishing
« on: April 07, 2024, 11:53:31 PM »
If this story sounds familiar, it's because I recently told some of it in reply to a tutorial by smart dog how to tune a L&R Queen Anne Lock.  I would love feedback on how I did, I'm trying to learn from my mistakes (there were many) and am happy for you all to point out the ones I haven't even realized.


I just finished polishing the lock and figured it was worth telling the full story and sharing as many pics as I have.
This lock was an L&R replacement for a T/C Hawken.  It started life with some issues, the worst the hammer was twisted and the flint had to be put in hanging out the side, it also would twist loose every 10-20 strikes.  After some troubleshooting, I found 2 main issues, the hammer wasn't seated fully on the spindle, there was casting boogers on the hammer and uneven cuts on the spindle's square  section.  I cleaned those up and reassembled, and found out that there was a deeper issue.  The hammer rotated off axis, like the spindle was bent.

 Further troubleshooting led me to find the tumbler had a weird shoulder that was not square to the spindle, instead of coming out at 90° it was closer to 95/85, causing the hammer to lean towards the lock no matter where it was in its rotation.  I think the assembler tried to correct this by bending the hammer but all that did was make it crooked and look like it was going to hit the barrel.


I'll post more replies with my journey through turning this ugly duck into something to be proud of (hopefully).  For now, here is what the lock looked like new.





save gallery net





Offline WonkyEye

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Re: Lock tuning and polishing
« Reply #1 on: April 08, 2024, 12:00:05 AM »
So the saga begins.  I didn't take pics a long the way, I never expected it to get this involved.  It started as a simple enough tweak...

To fix the uneven shoulder, I used diamond files and stones to square the shoulder.  Doing so caused my next set of woes, the tumbler face was also milled inline with the old shoulder, I now had high point that dug into the plate.  So again more filing.  I'm sure you guys who have worked on locks before realize at this point what a mess I'm and and my problems have only just begun.  I'm a novice and had no idea what I was in for.

So, I had my shoulder squared, the face of the tumbler was now parallel to the lock plate, my spindle is sticking out at 90°.  I reassemble for a test fit and find that the tumbler cannot rotate.  Of course the side of the tumbler facing the bridle also now has a high point, and needs to be filed down so it doesn't impinge on the bridle.  I finally get all that done (so I think) and have many hours into this already.  I reassemble and after some testing, quite proud of myself, fire it several times then out of nowhere it gets stuck at half cock on the way down. 

Queue ominous music...

I had reduced  the thickness of the tumbler, leaving a gap big enough for the fly to fall out.  At this point I'm panicking that I should have just sent it back.  Why did I do this?  Would they even take it back now?

After a a few deep breaths, I realize I can find the fly with a strong magnet and persevere.  I very carefully filed down the boss to leave just enough clearance, and ensure it mounts the bridle parallel to the lock plate.  Again I reassemble, only to find it still cannot rotate.  After much measuring, blueprinting with a sharpie, head scratching, I finally realized the axis of the spindle has been moved to be 90° with the plate, the bridle is now closer to the plate and the hole is now misaligned.  Tightening the bridle causes the tumbler to twist.  After debating several possible fixes, I chose heresy, the ultimate bubba move, I enlarged the 2 mounting holes for the bridle so it could be rotated.  I feel like a hack, but my welding skills are lacking.  If I had confidence I could fill them without voids and without warping the bridle I would.  I rationalize that between the 2 mounting holes, the screw for the sear, which serves as a 3rd mounting hole, and the tumbler pin and tight tolerances for the tumbler, I don't believe the mainspring could pull it out of position. This is an acceptable, if not ideal workaround in my opinion.

After finishing all of that I reassembled the lock and was quite pleased to find it functioned.  I was also too burnt out from my emotional roller coaster and probably 20 hours fumbling my way through it.

So at this point I reinstalled it in the gun, and went shooting several times.  And it worked, better than the old TC lock to boot.  At this point I'm quite proud of myself.  Next post I'll talk about polishing.

Offline WonkyEye

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Re: Lock tuning and polishing
« Reply #2 on: April 08, 2024, 12:20:34 AM »
At this point, I've shot a couple hundred rounds, the lock functions and is a big step up, but not great.  I've noted that the action is somewhat gritty, the hammer, the frizzen, even the trigger feel sandy.  The prime gets packed down into the pan by the lug on the frizzen (the pan is quite small).  I've had a few hang fires and failure to ignite, and trying to figure out why.   I also know I want to polish the outside of this ugly duckling.  In my mind I have delusions of grandeur in which I am able to engrave the lock with my jumping deer mark and some scrolls, and possibly a wheat leaf curling up the hammer.

The most pressing of the issues is the misfires, so I started there.  I recently switched to priming with 2f, so I switched back to 3f which I've always done, but it doesn't improve.  I also found that my flint was so stubby the top jaw of the hammer was preventing it from fully scraping the frizzen.  Seriously, the flint started as 7/8 and was probably no more than 1/2", lol.  I added a new flint, which seems to have fixed the misfires - user error aka too cheap to replace the flint.

But, the hangfires just don't make sense, same priming powder I've always used, same barrel, same charge, same gigantic touch hole.  At this point I read Bird Dog's tutorial on the Queen Anne Lock.  In it he mentions the frizzen lug packing down powder.  He also polishes the lock inside and out in the tutorial.  Coincidentally he encountered almost all of the issues with the lock internals as I have (His fixes were better and smarter, I wish I had seen his post before).  This was just the inspiration I needed to tune it up.  I started with the frizzen, I left just a hint of the lug in place, I didn't want to deal with pan misalignment issues, but I also largely hollowed out the lug and filed the notch he recommended so it will hopefully prevent packing the powder and fix my hangfires.  Apologies for the grime, this pic was taken after heat treating.

Next post will cover polishing internals and exterior.




Offline WonkyEye

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Re: Lock tuning and polishing
« Reply #3 on: April 08, 2024, 12:57:10 AM »
If you've read this far you're a trooper.

Following Smart Dog's example, I began the lengthy process of polishing.  I won't go into detail, he does a much better job explaining than I would anyway, not to mention he's a master and this is my first time.  I also had a very not flat plate plate, I flattened what I could, and left other parts if they weren't contact areas.  I still wound up having to shorten my screws and the nubs on the springs because of how much thickness I lost.  The tumbler faces were already polished from my earlier adventure.  I filed the bridle flat and polished the face to 600 grit. I didn't know how to deal with the spindle and nub for the bridle previously.  Smart Dog had the answer.  I mixed a slurry of green polishing compound and mineral oil, and smeared it all over the tumbler, spindle, sear and bridle, reassembled them and spent 20 mins working the hammer back and forth.  After cleaning and oiling they moved like butter.  I annealed the frizzen previously to file the lug, so I took advantage of its soft state to file and sand everything to 220 grit.  The roller was jammed up, I disassembled it, and could see rub marks at the bottom of the gap.  I used a diamond file to deepen the gap just a hair, and polished the inside faces to 600 grit.  I also used the green compound to polish the inside of the bearing and pin.  I annealed the hammer and spent an eternity sanding all the nooks and crannies up to 220 grit.  I polished the frizzen spring with 600 grit just to remove the forging grime.  And I file and polished the face and edges of the plate to 220.  I done have a forge or heat treating oven. I used a propane torch and a mapp torch to get the hammer, top jaw, and frizzen to cherry red and quenched in water.  I was concerned about the plate warping, so I didn't attempt to case harden it.  All I did was draw a straw temper to make it look pretty and match the frizzen.  For the frizzen I took the back to straw, but the tail to purple/blue.  I wanted a hard strike face, but resilience in the back end.  For the hammer I also differentially hardened it to leave the jaws and screw threads a bit harder, but went to pale blue in the middle section which seems weakest to me.

I was tempted to quench in linseed oil after tempering, it leaves a thin layer that I feel resists corrosion, but I had never heard of this so I refrained and just let the parts cool before soaking in 3 In 1 oil.

So here we are, lock is polished, works great, and looks fantastic to my eyes.  Please don't hold back though, if you see doodoo, say so.  I won't learn unless you do.

I have one unresolved issue with the internals that I noticed after putting everything together.  The main spring wants to pull out of the hole.  I'm almost 100% sure this is because the removed tumbler shoulder, it moved the linkage closer to the plate, and the end of the spring closer to the plate.  I suspect a shim/washer under the tumbler where the shoulder used to be, and probably a matching shim on the bridle boss will be necessary.  Then again, it might just be happening because that hole is saturated with 3 in 1 oil and might stop after I get the excess oil out.

It won't let me upload a video, but here's a slow mo of it sparking
https://imgur.com/gallery/nJ0ZUTC










Offline smart dog

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Re: Lock tuning and polishing
« Reply #4 on: April 08, 2024, 01:02:56 AM »
Hi Wonkyeye,
First, you deserve a big WELL DONE!  A lesser person would have thrown up their hands and given up.  In your case, you struggled but think of all you learned about locks in the process.   Perhaps the biggest lesson is that locks are "systems", which means you rarely can just fix or change one thing.  When you do, another issue but related pops up.    Something else to eliminate any anxiety you have about tinkering and polishing;  locks are not jet engines. The precision in 18th century clocks and watches is not needed for even the best of flintlocks. The CNC engineered and manufactured locks we have available are wonderful, but that precision is a luxury that is not needed.  The greatest flintlocks of all time were made by hand with only simple jigs and a few specialized tools.  So keep going and posting your experience. At the end, I believe you will have a good lock and a great deal of knowledge.  Feel free to PM me if I can help.

dave 
"The main accomplishment of modern economics is to make astrology look good."

Offline Daryl

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Re: Lock tuning and polishing
« Reply #5 on: April 08, 2024, 02:18:13 AM »
Well done Wonkyeye. I've a lock that needs polishing and I have been resisting doing that.
It works find, but doesn't make the rifle look as good as it could.


Daryl

"a gun without hammers is like a spaniel without ears" King George V

Offline WonkyEye

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Re: Lock tuning and polishing
« Reply #6 on: April 08, 2024, 07:46:12 AM »
If it's working well for you, don't let my story scare you.  90% of the time I spent was trying to fix the internals.  Not sure if you've done it before, if not, plan it out.  Decide whether you will aneal the hammer and frizzen so you can file them.

 The best advice I can give you is to slather hand cream on your hands before you start sanding.  It makes it a lot easier to wash the black crud off your hands.

Re: annealing...
Filing and using abrasives on annealed steel is so much less work.  If you leave it hardened you need diamond files and abrasives cut slower.  If it's annealed , regular files and sandpaper both cut quickly.  But it means you need a way to harden and temper later.  I.e. heat them cherry red.  A propane torch probably isn't enough, I used 2 torches together, 1 propane one mapp, an oxyacetylene torch would be a big step up, but I don't have one.  You have to understand how to temper so they don't shatter.

 Even though I annealed, I did cheat and use little sanding disks, burrs, and abrasive wheels means for die grinders and dremels.  Those were too fast and too easy to cause damage so I used them in a drill running about 1/2 speed.   Used the power tool to remove the rough casting finish and seams and marks.   I followed that with files, mostly fine cut to smooth the profile and remove high spots.  After that I hand sanded everything, with emery cloth starting with 80, then 120, 180 and finished at 240 making sure to go in the same direction.  That seems like a lot, but progressing through the grit is less work than skipping some.  The hand work is noticable, don't skip it, it really does look so much better.  I do the whole thing with one grit before I move onto the next.  I try to alternate directions so I can see that I removed all of the earlier scratches.  More on that below.

 After I heat treated, everything was black and grimey, it needed polished again, that's where the real time came in.  The steel was super hard and.sandpaper was slow to cut.  Every spot I messed up, every low spot I missed when filing before was very obvious and took 3x as long to correct.  Despite my trying to alternate directions, there were some areas I did poorly, and it was time consuming to sand away a dark grimey scratch from a file or coarse sandpaper that shouldn't have been there.

 Eventually I got it all shined back up.  Then I did the tempering that gave it the colors.

I did all of the initial polishing and hardening after work one night, maybe 5 hours.  And a few more hours the next day to shine it back up. Tempering and chasing the colors is the fastest part, so it makes sense to take your time, just hit the part with the torch for 2-3 secs, then wait at least 15 secs to see what happens.  If you over do it , a bowl of water nearby so you can quickly quench and stop it before it gets too soft is a good idea
Good luck.

Offline Daryl

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Re: Lock tuning and polishing
« Reply #7 on: April 08, 2024, 10:29:23 PM »
Tks for the suggestions. ;D
Daryl

"a gun without hammers is like a spaniel without ears" King George V

Offline Bob Roller

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Re: Lock tuning and polishing
« Reply #8 on: April 09, 2024, 12:33:21 AM »
That lock looks like it has part of the bridle cast into the lock plate.That's something I have never seen and wonder what prompted that idea?
Good looking exterior and I hope you can get the bug collection out of it.
Bob Roller

Offline WonkyEye

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Re: Lock tuning and polishing
« Reply #9 on: April 09, 2024, 06:12:44 AM »
That lock looks like it has part of the bridle cast into the lock plate.That's something I have never seen and wonder what prompted that idea?
Good looking exterior and I hope you can get the bug collection out of it.
Bob Roller
I'm new to this, haven't studied the internals of other locks.  The plate does not strip down to a flat plate like some I've seen. You're correct, it does have a boss for the bridle as part of the casting.  I didn't realize that was unusual.

Offline Bob Roller

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Re: Lock tuning and polishing
« Reply #10 on: April 10, 2024, 08:37:18 PM »
It's a production idea that was/is not needed.Externally that lock is good looking and I hope it can be used in the build,
Precision not needed? That's news to me.It enhances the overall quality and as I have said before,it tells the buyer what I
think of him or her as well as myself.
Bob Roller
« Last Edit: April 11, 2024, 04:00:15 PM by Bob Roller »