The Mainspring is slipping off the tumbler! How do I stop it?

[LawrenceA]

Makes a lot of sense.
Thank you all.

 

[Rudyard]

Re CVA locks Ide suggest take the whole rifle to your nearest river & ensuring no warden types are looking, give it the' buoyancy test'. Save you a lot of frustration . Or do your peening with a sledge hammer you might get more fun out of it that way ..More seriously these locks are notorious for being bad locks . They do make locks you can replace them with L&R Lock Co offer such locks I believe. If you will need to fettle them to fit .Others no doubt have had similar difficulties .I have never bothered with them .
Rudyard

 

[LawrenceA]

I looked at an L&R lock and to be honest it is just not worth it. I estimate the cost would be around USD300-400 landed.

This gun cost me all up maybe USD250, including a Lyman minie mold.
Certainly not expensive by any stretch. I think it has seen a lot of use and was not well cared for. Looking at it someone has been messing around with it a fair bit before me so maybe it is a lemon.

If I can get it functional and have some fun shooting rocks that is OK.
I have already had hours of entertainment scrubbing out the barrel (it took 3 days!), redoing the stock with tea stain and boiled linseed, filing off all the chrome and browning the metal work.
I am quite happy with how it came out. Perfect? Far from it but much better. Just need to improve the reliability.

There is nothing more satisfying for me than hands on "gun stuff".
Examining and fixing firearms, cleaning and refurbishing.
Casting bullets, reloading, shooting rocks and hunting. Even making shot.
ALL great stuff.

 

[Khufu]

Those Maslin flintlocks are not the best, I upgraded mine to a RPL and have never been sorry. faster ignition, and far more reliable.
just a thought.

 

[Khufu]

The L&R rpl is $185 US from track of the wolf, how much could shipping cost to get it down under?
when I bought mine they were $119, and the CVA barrels shoot real good, so the upgrade is worth it.

 

[Rudyard]

Dear Lawrence I admire your patience but think you deserve better .Couldn't some US resident buy you the spare spring & post it gets round that nuisance. There may be some forum reader has just such a spring ? most any spring of that aprox size might be adapted by some practiced even ameture gunsmith its not like you cant drill tap & rearrange the whole lock .Dixie did sell small springs so long as its within cooey you should be able to drill a new hole for the peg . How long is your spring from bend to tip of hook?
.If you post this dimension on the forum some one might have what you seek . I might even . The peening plan if crude might work fine Be better than what you have.
Cheers Rudyard

 

[LawrenceA]

I did a little more work on the lock with peening and stoning and I believe it is fixed.
Worked the lock about 40 times and no dramas.

Many thanks for your thoughtfulness and suggestions.
You have no idea how helpful it is to be able to pose questions and problems regardless of the obscurity and get meaningful answers.

I thank you all

 

[HoosierFrontStuffer]

I did a little more work on the lock with peening and stoning and I believe it is fixed.
Worked the lock about 40 times and no dramas.

Many thanks for your thoughtfulness and suggestions.
You have no idea how helpful it is to be able to pose questions and problems regardless of the obscurity and get meaningful answers.

I thank you all

If you still need a main spring I think the cheapest shipping would be 23$. Also have you contacted Traditions in Spain for a mainspring

 

[LawrenceA]

If you still need a main spring I think the cheapest shipping would be 23$. Also have you contacted Traditions in Spain for a mainspring

Hi Mate
I berleive the main issue is the tumblet and the wear in the sideplate which has allowed it to twist a little.
I have reshaped the area on the tumbler where the spring sits but have not used it much since so unsure if it is a permanent fix.

 

[ILoveMuzzleloaders]

I have the same issue can someone please help. As a gunsmith I am looking for ways to fix this. It’s a traditions PA Pellot rifle deluxe from what I’ve been able to gather. I bought a new tumbler for it and cut a third position into it in hopes that it might stop the mainspring. It doesn’t. It will do half cock just fine but completely falls off if I do a full trigger pull if it’s guided down ( decocked) slowly it works fine and hangs onto the nose from tension. I’m thinking a new mainspring?

 

[ILoveMuzzleloaders]

Here are some interior pictures

 

[PhDBrewer]

Based on the image....
I'm guessing a new tumbler & sear. I do not think I have seen such a deep notch!
Edit: I have never seen a CVA lock. Did not realize they had such a deep half-cock position. With that being so, does the sear tip need to be more pointed? The round tip does not appear to "seat" fully in the full-cock position.

 

[necchi]

Ya have to replace that screw that holds the hammer to the tumbler.
Your last photo "enlarged" shows the tumbler a few thousands away from the lock plate, it needs to be in contact with the plate, but not binding tight.
With those unbridled locks the lock plate is the guide and bearing for the tumbler position. Without that screw the tumbler can/will easily "tip" out of position allowing the spring to slip.
And they need lots of fresh gun oil.

p.s. the "Deluxe" has a double trigger and a different bridled lock. Your replacement tumbler, may be the wrong tumbler for that lock.

 

[IanH]

I think the OP and Ethan are both having the same problem but for different reasons.

The OP's mainspring nose was definitely ground crooked but without pins to locate the bridle and the tunbler/plate fit likely very sloppy or worn, he likely inadvertently snugged the bridle down in a rearward location causing the tumbler axle to be out of square to the lock plate, causing the spring to slide off.

Without a bridle, same thing happens with wear. Maybe add a thin, brass bearing shim to the tumbler shaft on both sides of the lock plate? I don't know the best way but as a machinist there are some things I would try in order to provide some bearing support to the tumbler and keep the axle snug and square to the plate.

 

[necchi]

Based on the image....
I'm guessing a new tumbler & sear. I do not think I have seen such a deep notch!
Edit: I have never seen a CVA lock. Did not realize they had such a deep half-cock position. With that being so, does the sear tip need to be more pointed? The round tip does not appear to "seat" fully in the full-cock position.

He's modified the tumbler in experimentation.( it's how we learn, nuthin wrong with that) It's after an market tumbler, there should be a fully drilled/taped set screw for the sear engagement

 

[necchi]

but as a machinist there are some things I would try in order to provide some bearing support to the tumbler and keep the axle snug and square to the plate.

Your right, a shim can be placed between the hammer and plate to "snug up" the tumbler.
But these unbridled Spanish locks are notorious for excessive wear from user neglect at the tumbler/plate interface.
There are several techniques that can be used to "bandage" the damage to the worn lock plate.
Having .001-.005 brass or steel sheet shim stock can be your friend,, but it's just a band-aid.
Simple advise, avoid the unbridled Spanish locks.

 

[FlinterNick]

It’s a geometric error in the lock’s assembly that is causing the mainspring to slip.

The lock looks like it’s misaligned, likely the bridle and tumbler fit, which is why the bridle screw was loosened.

The mainspring is moving because the tumbler is pushing it to the side, and it’s possible the mainspring isn’t set in correctly, it could be either too close or too far away.

Polishing it will not help.

I would disassemble the part the screw in the bridle without the tumbler, then attach the sear,, if the sear is not pivoting freely, then the bridle has been incorrectly placed, the tumbler arbor will pull against the bridle’s location, causing it to slip.

For correction, I would weld up the bridle or find a blank bridle, then have the bridle reset on the plate. Other complications could be the sear might be located too far away, but if the bridle is large enough, that shouldn’t be an issue.

In the picture, you can see the screw hole on the bridle is elipsed slightly by the gap in the picture, this is causing the entire internal function to misalign.

Not the hardest thing to fix, with a drill press, i woudln’t get a new mainspring until I’ve attempted to correct the bridle.

I can assist, PM me if you need further assistance.