Broken Main Spring

[davidthered]

Horror of horrors, my new Pedersoli 2cd Model Brown Bess wouldn't fire last Sunday. It had fired fine the day before, but now as I half-cocked it... mush!! :cry:
Took the lock off and ... dang!!! The Main Spring was busted! :curse:
I've heard from others that this is common with the Pedersoli's, what sayist thou?? Anybody?
What I need now, is a maybe step by step instruction on how to replace the spring, and what to watchout for. A link perhaps? or can that info be found somewhere on this Forum??
Thanks for any help you can give me.

 

Now you get to find out how good your customer service dept. really is! This could take 48 hours with a quick phone call, or it may turn into one of those projects you finish after retirement.

TOTW has mainsprings and spring vises if all else fails.
If you do not know how to replace a mainspring you need to get a book on BP gun assembly or repair. you're going to need it with that Italian and Spanish stuff. The Gunsmith of Greenville County is good. Or you can look at the parts relationship and just "fiure it out" and use a pair of visegrips to compress the spring.

I would buy an extra spring in the order. They are cheap insurance. I have broken two or three over the years. The only ones I really remember are the ones on off brand locks that were impossibe to replace. That's when all that "junk in the big box" comes in handy and you remember why you never throw anything away! It may not fit perfect, or you may have a new hole in the lockplate, but it works.

I have documentation that the Chiskasaw made replacement mainsprings from pieces of hickory. That is always an option!

 

[Stumpkiller]

Really makes you appreciate our forefathers who could turn out flawless flintlocks and well-tempered springs before homogenous steel, CNC milling machines and electronic tempering furnaces.

Replacing a Mainspring

This site might help. At least it talks you through the process.

Get thee a spring vice. (Sounds like you'll be needing it :shake

Let's hope it's just a fluke in the happy partnership of you and your musket.

 

[Zonie]

As Stumpkiller said, you really should buy a Mainspring Vise and an extra spring.
The Mainspring vise is not strong enough by itself to compress the spring. It's really designed to hold a compressed spring in it's compressed state while you position it in/on the lockplate.
As this small Mainspring vise is not designed to compress the spring, I would recommend buying a small vise to do this task if you don't already own one.
Vise Grips have been used to do this, but I've personally known these to break the new spring because they are limited on where they can apply the pressure. The pressure should be applied to the full length of the lower arm against the upper short arm.

You will not have to dissassemble any part of the lock to install the new spring.

By all means, wear safety or shooting glasses while doing this work. If the spring slips or breaks during this process it can put your eye out.

With your new spring in hand, compare it against the lockplate and the tumbler to get an idea of how much compression will be required to assembly it with some clearance between the tip of the spring and the tumbler when it's in the "hammer down" position.

Also check the springs side pin fit with the hole in the lockplate. This fit should not be tight. It should be snug but easily assembled with hand pressure only. If it is very tight, insert it into the side plate and rotate it back and forth about the pin's axis while inserting it to enlarge the hole slightly and produce a custom fit.
With the spring pin inserted into the lockplate hole, rotate the spring counterclockwise as far as you can and temporarly install the Mainspring vise. This is done to determine how much of the spring will protrude from the Mainspring vise during the spring compression operation.

Position the spring in the Real vise until the mainspring vise touches the real vise jaws.
Compress the spring until it looks like it will clear the tumbler. Now compress it just a little more and retighten the Mainspring vise good and tight.
Release the spring/Mainspring vise assembly from the Real vise. Engage the springs side pin into the sideplate hole and slide it into position. It should seat out against the lockplate.
My pictures of a Bess lock don't show a retaining screw, but if your locks spring has one, now it the time to install it.

**** the hammer to the Half-**** position and the Mainspring vise will fall off of the assembly.
Your done!

Position
::

 

[davidthered]

Well, I got the Spring in the lock, used my vice-grips with a cotton patch to keep the spring from getting scratched or indented. Worked fine. With the lock off the gun, I can half, and full **** the lock, but when I put it back into my Bess... the trigger does nothing!!??? Feels mushy and does not engage the lock. :curse: :cry:
Took the lock off again to see if I busted the spring, nope, spring is fine, and it looks like I have all the pieces back where they were.
Can anybody give me a clue as to what I'm doing wrong?

 

[Stumpkiller]

Did you press the trigger as far forward as possible (opposite of a normal pull) when setting the lock in place? You may be setting it in with the sear arm BELOW the lever of the trigger. It's also possible that the new mainspring is contacting the wood inside the lock mortise. You may need to CAREFULLY remove some of the wood where the lowest forward portion of the spring contacts the stock. With the lock off and viewing from the hammer side do you see any of the spring projecting below the sideplate?

Soot up the spring with a stick match or a candle and see if it rubs off when set in place. Remove the sooty wood until it stays clean (a Dremel w/drum sander bit is excellent for this. Work carefully and slowly, being extremely careful not to "zing" the wood where it shows around the lock mortise).

Let us know.
.