lock take down , tune & put back together

[projeeper]

many of you have done this 100s of times but somewhere someone taught you how to do this the correct way,what tools to use where to get them or  how to make them.
 there is a polishing tutorial
 how to make a brass lock plate tutorial
 but not the task of taking a lock apart correctly and properly tuning it
 to many of us NOOBs i,m sure this would be a most useful tutorial

[Blacktail]

I'm a noobie myself. That being said, nothing seems really difficult about it. All I can say is get and use a mainspring vise and don't lose the fly. I heard about this guy one time who learned those things the hard way. 

[Sam Everly]

Telling a fellow how to tune a lock , would be about as hard a subject as you could find . Every one has somthing different that needs fixing . Some need very little work, some need thrown away, then start with a new lock.       

[Acer Saccharum]

Get two of the same lock, and I'll bet they need different fixes.

This is an interesting topic.

One of the biggest problems is fits of tumbler notches and sear nose angles. This is related to the 'template' idea that Rich pierce mentioned about building locks.

Another one is the sear screw clamps the sear down before the screw tightens on the plate.

When should the frizzen flip? Why does the frizzen bounce when it flips open? Why don't I get more spark? Why does my flint shatter?

This is a very wide subject, which could be covered in a multi part tutorial. A lock is extremely complex, and the geometry of one part is completely co-dependent on the other parts. A quick and easy answer is not possible.

Tom

[rich pierce]

I've saved a couple articles on this.  could photocpy them and mail them to you.
rpierce@dom.wustl.edu

Off the top of my head in disassembling a lock:
1) Bring to full cock, install mainspring vise, tighten vise, let cock down, and remove the mainspring.
2) loosen the screw for the sear spring most of the way.  pop the spring away from the plate, remove sear spring.  Then remove screw for the sear.  Then remove the screw remaining for the bridle and set all these in a cup, etc.
3) loosen the cock retaining screw 2 full turns.  Now bop that screw real good with a copper or brass hammer or a hardwood mallet, driving it toward the plate.  This should loosen the cock from the tumbler.
4) Remove cock retaining screw, tumbler AND FLY.  Tape that fly to the cock.  Double tape it.
5) bring the frizzen to half-open and then grip the frizzen spring with a pair of vise-grips etc.  Tighten a little more.  Remove frizzen spring retaining bolt then the spring then the frizzen retaining bolt and frizzen.

Tuning or polishing?
Most locks will improve function by being properly polished and making sure nothing is scraping on the plate.  But if you reduce dimensions by polishing, you may have significant problems.  You want to improve function, not get a mirror finish with no pits etc.  The castings always have some pits and you may not be able to get them all.

Polish:  Foot of frizzen, top of frizzen spring, and very carefully, buff the frizzen pivot screw (don't overdo it on the screws or things get worse).  If the working arm of the frizzen spring scrapes the lockplate, file it carefully till it does not.

Polish: nose of mainspring and the cam on the tumbler where it rides.
If the working arm of the mainspring scrapes the lockplate, file it carefully till it does not.

Polish: upper arm of sear where the sear spring rides on it.  Polish the sear spring where it contacts the sear.  Make sure the sear spring is not scraping the plate when it moves.  VERY CAREFULLY polish the sides of the sear that contact the lockplate and the bridle so it pivots smoothly.  If the sear has a bearing that contacts the bridle and the plate, preserve this at all costs.  You must be careful to never remove too much material.  Never round any surfaces.

Polish:  the inside of the bridle where the tumbler side may contact it.  Polish both sides of the tumbler so it rotates smoothly.  If there are "bearings" or raised rings at the axle of the tumbler preserve them at all costs.

Now assemble the tumbler, bridle, and sear and see how they all rotate and move together.  Test for slop because when they are under pressure, they will pivot.  Decide whether or not you need to shorten the "legs" of the bridle.  If so, go very slowly and allow a smidgon of daylight between the tumbler and plate, tumbler and bridle.  Same with sear.

Tuning requires more expertise and willingness to replace parts if you mess up.  Never live with an unsafe lock that will not hold at half cock or full cock.  tuning may include careful stoning of tumbler notches and the sear nose so they mate perfectly and are at the correct angle.  It could involve increasing or decreasing the depth of the full cock notch, lessening the power of the sear spring, changing the timing of the frizzen opening, adjusting the power of the frizzen spring to better match the mainspring, adjusting the stop of the tumbler by the bridle and the cock ledge, or other things.

To reassemble the lock, I put the frizzen and spring on first.  Then the tumbler with the fly in the correct orientation, then the bridle, then sear, sear screw, sear spring and screw, pop the sear spring into place. Install all tumbler screws.  Put the cock on and whap it good to settle it on the square tumbler shaft.  Tighten cock retaining screw.  Lower the cock to "fired" position and install the mainspring.  Bring to half cock and release the mainspring vise.

[J.D.]

3) loosen the cock retaining screw 2 full turns.  Now bop that screw real good with a copper or brass hammer or a hardwood mallet, driving it toward the plate.  This should loosen the cock from the tumbler.

I have stripped screws by smacking them with anything resembling a hammer; brass, plastic, wood, or otherwise.

A brass punch a coupla inches long with a square ground on either end, to fit the square hole in the cock, prevents damage to either screw or female threads in the tumbler.

God bless

[jpldude]

Lock Tuning for Idiots (IOW me!)

Greetings, I was the lucky winner of one of the unmarked Charleville Locks on EBay. I thought somebody would outbid me, but nobody did, 1 more penny & it would have been yours!

Anyway, when I got the thing, it was quickly apparent that it wasn't remotely near a Jim Chambers lock. The flint would literally crash into the frizzen, open it 1/8-1/4" & then everything would stop, and worst of all, no sparks.

Over the last few years I have made Dixon's & listened to Keith Castille's seminar on lock tuning. My choices were a $100 boat anchor (& not a good anchor at that) or what the $#*!: try what Keith has been telling us to do for years: eliminate friction & scrubbing.

#1 was to strip the lock. Sure enough, the inside of the lock plate was "as cast". IOW rough & pebbly! Too much friction! I took sandpaper & files & got the inside of the lock as smooth as I could. I then polished it on my cheapo Sears polisher & had it shining like a new nickel.

#2 was the main spring. Three things needed doing: First, sand the spring on the belt sander so it would not "scrub" the lock plate, IOW you need to sand off just enough to see a "wee smidgen" of daylight between the spring & the plate. Two was to carefully round the toe of the spring where it rides on the tumbler and finally #3 was to polish the entire spring.

#3, the tumbler was next. It already had a small ridge on the plate side, so the whole thing wasn't riding on the plate, finally a break! I tried to put it back in the plate & it wouldn't go back in!! Holy smokes, talk about too much friction! Hmm, Keith didn't mention this problem, what to do? Well, I also went to Jim Chamber's seminar & he mentioned that he lathe turns his tumblers & reams his plates, so the fit is .001" or better. I don't have a lathe (Hint to Santa), but I do have an electric drill & emery cloth. I chucked up the tumbler in the drill, clamped the drill in the vise, cut a strip of emery cloth & went to it. Well not quite, I had to trim the emery strip 2 more times to get it small enough. After a minute or so it went into the plate, no problemo. I also polished the tumbler where the the toe of the mainspring rides.

#4 I didn't want to fool with the sear too much, so I rounded over the nose on the belt sander & polished it.

Time to test it out… I put the lock back together, but instead of using a 12 lb sledge to put the hammer back on the tumbler (like Gepetto did), I used a small hammer & a block of wood & made sure the hammer stood off from the lock plate just an ooch so it wouldn't scrub the lock plate. I found a new flint, positioned it correctly in the jaws & !@*%&@ if it didn't have a 15 lb trigger pull, I finally got it go off & darned if the flint didn't smash into the frizzen, throw 2 sparks & come to grinding halt part way down the frizzen.

Ok, time to go into scientific analytical mode. What hadn't I fooled with? The frizzen spring, maybe it was out of balance with the main spring, Keith had said something about that. Hmmmm, OK, how to test the theory? I remembered that Wallace Gusler used some funny words in "The Gunsmith Of Williamsburg" video, he said something like "the frizzen spring needs to be strong enough to keep the frizzen from flopping around". Not quite how Keith put it, but it got me to thinking. I took the frizzen spring off, set the cocked lock across the palm of my hand & with my thumb, I held the right side of the frizzen shut & with my middle finger, I held the left side of the frizzen shut. I applied just enough pressure with my fingers to keep the frizzen from "flopping around". I tripped the sear & holy sparks batman! I had everything I wanted: sparks to make Jim Chambers proud & and a fully opened frizzen.

OK, back to the belt sander & the bucket of water. I ground & I ground & I ground some more. I finally got the frizzen spring thin enough to where I could pinch it not quite halfway closed, maybe a 1/3. Back onto the lock & bingo, sparks & the frizzen fully open. But wait: now the frizzen flops around in the open position because the toe & heel of the frizzen no longer contact the top of the frizzen spring. Darn, I had ground off too much at the top of the spring where the toe rides. OK, I gave up on propane, mapp gas, little oxygen bottles & little mapp bottles; I got sick & tired of going to Home Depot every time I needed to get something hot, so I bought a full blown OxyAcetylene setup,  I highly recommend it. I found my Brownells Heat Stop Paste, made a big ball of it around the bend of the spring & heated up the spring where the toe of the frizzen rides & put just a little hump in it. Success! The toe & heel of the frizzen stay in contact with the frizzen spring regardless of whether the frizzen is open or closed.

Cock the lock, close the frizzen, press on the sear, press on the sear, really press on the sear & finally good sparks & a fully open frizzen. What about the sear? Well looking at it, it was very apparent that it could double as a garage door spring, so I took it to the belt sander & gave it the frizzen spring treatment. I also rounded over the toe & polished it. Much better: a reasonable military trigger pull, sparks to beat the band & an open frizzen. IOW, I now had a real, usable lock.

I put a few drops of Ballistoll on the contact points tried it again & same as before: good sparks & an open frizzen. Since it's humid here in Houston, I sprayed the lock down with WD40 & decided to call it a day. But since it worked so well, I just had to try it one more time. Cock the hammer, close the frizzen, trip the sear & WHAT!!! 1 lousy spark!!! Not good. How could I go from good to bad in 5 seconds?? Back into the scientific analytical mode, could it be the WD40? I wiped the frizzen with a little mineral spirits & tried again, whew, big sigh of relief, my sparks were back.

Well that's my story on lock tuning. I found it well worth the effort & I have an even better appreciation for the work that Jim Chambers & all the lock makers put into a quality lock. Give it a try before you throw that lock into the junk drawer.

Rgds,

[Dphariss]

many of you have done this 100s of times but somewhere someone taught you how to do this the correct way,what tools to use where to get them or  how to make them.
 there is a polishing tutorial
 how to make a brass lock plate tutorial
 but not the task of taking a lock apart correctly and properly tuning it
 to many of us NOOBs i,m sure this would be a most useful tutorial

There is no tutorial that can cover all of this.
It has to do with so many things.
Springs are a part. One set of cast springs is fine the next that look just like them are pitched in the trash, Mains springs especially.
A lot of tuning is almost  by feel.

Does the flint point at the pan? Does the cock stop to soon? (just ran into this with a store bought)
Does the frizzen kick open like it should. If not first make sure its not rebounding and then  adjust the spring or roller or frizzen foot till it works right.
Case harden the lockplate at the tumbler hole. Case harden the bridal. Don't need a really high temp quench. If the lock parts though harden they will need to be drawn back to blue or at least a tan color to preven breaking.
If the lock is cast from an original lock the springs are probably not arched right. I had to re-arch both the frizzen and main spring on the store bought. Sometimes I make forged springs but this is kind of a PITA.
If the frizzen does not spark it may be to hard, the wrong alloy etc. Put the frizzen in a preheated oven at 375 degrees. If its soft harden it. If it has a chronic failure to spark it may be cast of a none sparking alloy like 4140. This requires facing the frizzen with high carbon steel.
If the mainspring bears of the tumber directly put a high polish on boith  bearing surfaces and a small dab of high tech firearms grease type lube.

Etc etc.

Bed time.
Dan

[Don Getz]

One of the little things I also do in cleaning up a lock.   I have some 600 grit paper which I wrap around a dowel, just
big enough to go thru the tumbler hole in the lock plate.   I willl then spin the plate on this "polishing" dowel, does a great job of polishing that tumbler hole but removes little or no metal.  One other comment....."rounding the nose of the
sear "   This isn't really the thing to do.......I don't care where you may have read this............Don

[Bill of the 45th]

A big note on disassembly.  The fly may look symmetrical at first glance, and may seem to be able to be installed either way, but will only work one way.  So take extra care to make sure which way it goes when removing.  There's nothing like getting to assemble the lock twice.   I did get a good deal on a large Siler, that a guy thought was defective, and all that was wrong was the fly being backwards.  I use a tupperware tray to hold my disassembled lock, and put a two to three inch piece of two sided carpet tape in the bottom to hold the screws, and fly.

Bill

[Acer Saccharum]

Why do you think it's called a 'fly'?

Don, you CAN round the sear nose a bit on a single trigger. As long as it's deep in the notch, it is as safe as a square notch. A slightly rounded nose helps the sear ride over the halfcock without milling metal off the tumbler.

A gun with a set trigger should have a square nosed sear, and a fly is mandatory.