Lock question

[KNeilson]

Gents, I have noticed something in my lock ( large Siler) that concerns me. This is not the original tumbler that came with the lock, the half cock notch broke in the original so I replaced it. I`m concerned that the spring may slip by, or the tip of the tumbler may break and then the spring gets to wreak havoc in the lock mortice. I can add a bit of metal to the cock stop like in the pic to fix, but then I dont know if I should harden or heat treat the cock when I am finished... any advice?........  Kerry

[Acer Saccharum]

Kerry, that looks like an excellent fix idea. I wished I'd thought of it.


Most parts are NOT heat treated when you buy a lock. Only the more fastidious builders heat treat or case harden their own locks. So if you have not heat treated the cock in a past life, then it is not heat treated now.

Test: try a file on it.

I see no harm in building up the shoulder on the cock and then reshaping.

Tom

[Swampwalker]

A second possibility - move the mainspring back a little bit, by welding/silver soldering the mainspring mounting hole, and re-drilling slightly rearward of it's current position.  I won't take much.
A third possibility, re-bend the foot of the spring to stretch it out a bit - this would require re-tempering the spring when you're done.

[JTR]

Another option would be to get a new hammer, but I agree with Acer that welding up the shoulder and reshaping is an easy solution.

Pretty much for sure if you use it as is, something is gonna bust,,, and the spring Will wreak havoc!

And you really don't need any more havoc right now!

John

[Frank]

Get a new tumbler from Jim Chambers.

[KNeilson]

Gents, thx for the responses......Its great to see my problem thru other eyes! I am a welder so building up a little material either on the cock or the spring hole will be the solution this time. Depending on the C content of the material usually will tell you the potential success of a weldment. I was worried they might use the same steel for all parts, but was unsure about how they have been treated. Thx Tom, I wont worry about this now. Swampwalker, thx, didnt even consider moving the spring, I like this idea better than welding on the cock now. If the spring can move back a little without the nose hitting the tumbler axle I will be doing this. Solution #3 it too much work for me atm, I`d rather not screw with the spring. John and Frank, I agree a new part whether tumbler or hammer is the most correct way of repairing such and did consider this, but thought with modern casting methods they would all be very similar in size or dimension. Do you guys notice a fair size difference in mix and match type of parts interchanging? Thx again for your help.......  Kerry

[Birddog6]

I have had several locks like that. On two I had a couple of year ago, it appears the mainspring pin hole position was off just ? 1/32" ? or so, maybe the drilling jig got off a tad, etc. Since I had bought the locks new I just had them swap them out with dif. locks. However if I had one that I couldn't swap, I would weld the hole up & redrill it back just a tad to put the spring nose a lil deeper into the shoe, which is what I did on a used rifle I had one time..
After doing so, you need to insure the nose of the spring doesn't bind into the tumbler or the bridle when you cock it, as if it is too deep you have a new issue to deal with.  

[Cody Tetachuk]

A few more things to consider. Shoring up the hammer stop as shown in the pic will create undue stress on the hammer and the square tumbler axle IMO. Ideally, you want the hammer shoulder to contact the plate at the same time as the tumbler stop contacts the bridle (right between the bridle screw and scear spring screw) to spread the impact over the two stopping points. If you lift the hammer, the full force of stopping the tumbler rotation is born entirely by the hammer as the tumbler stop will not reach the bridle. While many locks come new with the hammer engageing the plate before the tumbler engages the bridle, this is something that, IMO, should be remedied as part of standard lock tuning which requires REMOVING a slight bit of steel from the lock shoulder, not adding. If you choose to relocate the spring, be aware that, should you choose to brown or blue the lock, the welds may not colour the same as the parent material and will show. Before making any mods, I would recommend contacting Jim Chambers directly and asking his advice.

[KNeilson]

Birddog6, Cody Tetachuk, thx for the reply. I ended up moving the spring last nite.

After doing so, you need to insure the nose of the spring doesn't bind into the tumbler or the bridle when you cock it, as if it is too deep you have a new issue to deal with.

Birddog6 ,I checked to see how far it would move to avoid this and ended up taking a minute bit of the springs end anyways, (.010 maybe). Now the engagement with the tumbler shoe is smooth and of no question. Another thing I noticed right away, with the spring riding deeper in the shoe there is not as much force delivered to the hammer, however it feels smoother thru its arc when cocking. It seemed to spark the same if not better, and I just tried it at the range and I think it actually performs better than before. I had already lightened the trigger pull a bit and now it is much nicer yet, I will measure later.

If you lift the hammer, the full force of stopping the tumbler rotation is born entirely by the hammer as the tumbler stop will not reach the bridle. While many locks come new with the hammer engageing the plate before the tumbler engages the bridle, this is something that, IMO, should be remedied as part of standard lock tuning which requires REMOVING a slight bit of steel from the lock shoulder, not adding.

Cody, thx, I didnt realize there was a tumbler stop, I will be looking into this later today. The hammer is starting to mark the plate a bit, maybe this is why. If I`d had to lower the hammer before I woulda been in trouble, now I have a little extra to let it down if need be. Great advice guys.....thx...........  Kerry

[Acer Saccharum]

I understand where you are coming from Cody, on the tumbler stop. In an ideal world, the tumbler will contact the bridle stop at the same time as the hammer contacts the plate.

No locks I have bought ever have been tuned to that level of precision. Practically speaking, I believe that the cock stopping on the plate is much preferable to the tumbler stopping the forward motion of the cock.

Tom

[D. Taylor Sapergia]

When you think of all that energy and momentum coming to an immediate stop, whether it's the cock's shoulder against the top of the plate, the tumbler against the top of the bridle, or both, it is amazing that there is no damage really.  A lot of the energy gets absorbed by the frizzen/flint interaction, and the feather spring.  Dry firing is another matter.  I've heard of the head of the cock being carried away from its momentum without the interference of the frizzen.

[Acer Saccharum]

Below is a pic of the very thing Taylor speaks of. Firing the lock without the frizzen closed. Tsk, tsk, and such a fine lock.

[Cody Tetachuk]

No locks I have bought ever have been tuned to that level of precision. {/quote]

And nor should they be. For the price that Jim sells them for, they are an incredible bargain and one SHOULD expect to do some tuning IMO.

Practically speaking, I believe that the cock stopping on the plate is much preferable to the tumbler stopping the forward motion of the cock.

Tom

This is why when I adjust these tolerances, I try to leave the hammer a few thou "proud" if you will, as the hammer being somewhat soft will sorta swage those few thou until the tumbler contacts the bridle and the lock finds it's own equilibrium. 

[rich pierce]

More reasons why case hardening lockplates and other parts not normally hardened on commercial locks can be helpful.

[Jim Kibler]

Here's my bit of advice...  While a stop for the tumbler and the cock makes a lot of sense and may seem like an ideal situation, I don't think it's really necessary and in fact not possible with many lock designs.  It seems the flint and frizzen slows down the cock sufficiently to avoid problems.  I've never heard of a problem with the tumbler or cock from the situation being discussed.  Oh, I'll take a case hardened lock plate any day.  They're a good thing.

[Long John]

Another solution you might want to consider is slightly increasing the radius of curvature of the bearing part of the mainspring.  This would necessitate heating to bright orange and a single hit with a hammer while the bearing part of the spring is on a rod or anvil horn of slightly larger diameter than the arc of the bearing part of the spring.  Then you must reheat treat the spring, of course.

Best Regards,

JMC.

[KNeilson]

Gents,thx for all the responses. I had another day at the range, the lock performed as it should, missfired once after 50 or more shots, but this was more my fault as I had done NO cleaning or maintainance during this time. There were several other more experienced guys there and they both commented that it ( the lock)seemed to be working very well. Then I ran out of 2F Goex and had to use some Pyrodex P (3F), another major change it seems... it was more sensitive to cleaning, made a FFsssssssssT boom sound, but flattened the trajectory a lot. So much to learn, too little time......K

If you lift the hammer, the full force of stopping the tumbler rotation is born entirely by the hammer as the tumbler stop will not reach the bridle. While many locks come new with the hammer engageing the plate before the tumbler engages the bridle, this is something that, IMO, should be remedied as part of standard lock tuning which requires REMOVING a slight bit of steel from the lock shoulder, not adding.

I looked at my lock, and with the cock down there is roughly .040 gap @ the tumbler stop. If I was to file the lock plate to close this up I`d end up possibly hitting the bottom of the pan with the nose of the cock jaw. I have ordered a few spare lock parts from TOW and will be modifying these to suit upon arrival, will post results......  Kerry

[Stophel]

Another solution you might want to consider is slightly increasing the radius of curvature of the bearing part of the mainspring.  This would necessitate heating to bright orange and a single hit with a hammer while the bearing part of the spring is on a rod or anvil horn of slightly larger diameter than the arc of the bearing part of the spring.  Then you must reheat treat the spring, of course.

Best Regards,

JMC.

The "hook" of the tumbler could likewise be bent upwards.

If it were me, I'd get one of the "blank" cocks from Track of the Wolf, and fit it, and make myself a new bridle (sawn out of 3/8" thick mild steel) and fit everything together the way I want it....but then, I'm a glutton for punishment, and I do just that all the time.   

[KNeilson]

Another solution you might want to consider is slightly increasing the radius of curvature of the bearing part of the mainspring.  This would necessitate heating to bright orange and a single hit with a hammer while the bearing part of the spring is on a rod or anvil horn of slightly larger diameter than the arc of the bearing part of the spring.  Then you must reheat treat the spring, of course.

Best Regards,

JMC.


The "hook" of the tumbler could likewise be bent upwards.
 JMC, Stophel, I elected not to screw with the mainspring or tumbler as I think it would be more work to "get it right" than just re-drilling the mounting hole. Which is now done and took about 1/2 hr. Ive just ordered a bunch of spare lock parts and will be adjusting to suit when they all arrive. Thx for all the responses......Kerry

[J.D.]

If I read this right, if you are a welder, just build up the top, back of the bridle where the tumbler should make contact. File the built up area down slowly, carefully, until the tumbler stops on the back of the bridle, as the cock stops on top of the plate. IMHO, there should be an ever so slight gap, so's the cock stops first...just a coupla thou, to compensate for peening the top of the lock by the shoulder of the cock, over time.

That said, IMHO, the tumbler taking the brunt of the impact of the moving parts, by stopping on the back of the bridle is much worse than the cock taking the full brunt of the impact with the top of the lockplate. A lock where the tumbler strikes the bridle too hard, will self destruct rather quickly, compared to a lock where only the cock stops forward movement of the moving parts.

IMHO, filing the plate would get you back to the place you were, with the hook of the main spring and the end of the horn on the tumbler.

In fact, anything that will alter the rotation of the tumbler will, effectively, reduce the length of the horn on the tumbler, and put you back where you were, in  the beginning.

IMHO, the idea of the cock and the bridle stopping the forward motion of the moving parts simultaneously  is an ideal situation, not the common situation. In my experience, few locks have the ideal geometry to stop on the cock and bridle simultaneously. Those locks, with less than perfect geometry, have survived quite well over long periods of continuous use.

IMHO, all in all, once you have a safe spring to tumbler relationship, I would leave well enough alone.

God bless

[KNeilson]

JD, thx for the comment.

If I read this right, if you are a welder, just build up the top, back of the bridle where the tumbler should make contact. File the built up area down slowly, carefully, until the tumbler stops on the back of the bridle, as the cock stops on top of the plate. IMHO, there should be an ever so slight gap, so's the cock stops first...just a coupla thou, to compensate for peening the top of the lock by the shoulder of the cock, over time.

the tumbler taking the brunt of the impact of the moving parts, by stopping on the back of the bridle is much worse than the cock taking the full brunt of the impact with the top of the lockplate. A lock where the tumbler strikes the bridle too hard, will self destruct rather quickly, compared to a lock where only the cock stops forward movement of the moving parts.

Thx for the suggestions, pretty well what I had planned. Ive ordered some spare bits including a bridle to do as you suggest. I didnt really like the idea of filing the lock plate, woulda rather have added to the cock, but moving the spring seemed better. Now that thats all done I`m more than satisfied with the performance. After getting back from the range today, Ive noticed another small clearance issue. The edge of the spring has barely rubbed a bit of the brown off the barrel in the lock mortice. I had clearance previously so will be removing a sliver off the springs edge where contact is. Big smile on to-day....  Kerry

[smylee grouch]

I hope I havent missed something here, but could you replace the tumbler with another Lg. Siler tumbler since they are available. Is your lock one of the delux Silers?  Good luck with what ever route you take.    Gary

[KNeilson]

Gary, The original tumbler had broken in the half-cock notch the second time I cocked it. This one was a replacement from TOW. I have a Chambers tuned Siler that I am refering to to "see" what should be correct. I have tried the tumbler and bridle from that lock to see how it fits and it is the same as mine. Just the way the holes are drilled is a little off...  Thx......  Kerry

[KNeilson]

Here is a pic of the spring (moved), and the bridle stop as is........  Kerry

[D. Taylor Sapergia]

Though you have taken care of the problem, it was not necessary to be quite so ... aggressive.  The tip of the spring can come right down to the end of the tumbler nose without any danger.  As long as the spring does not contact the plate bolster, or the tumbler's axle,  at full cock, you are good to go.  I would not cut away the cock's contact foot to make the tumbler contact the bridle...the cock will fall too far forward, and its lower jaw will contact the fence, and the flint possibly strike the pan.  It's fine as is, if it works.