Ever narrow a mainspring?

[draken]

I've run into a dilema with a rifle I'm working on.  Inletting the mainspring I am REAL close to cutting into the barrel channel.  I see no other alternative than reducing the width of the spring by grinding away roughly 1/16"   Can I get away with this without changing the strength of the spring?  It is a large Siler flintlock and a "C" profile Rice barrel.

[PPatch]

Cutting into the barrel channel is not too unusual when inletting a lock and generally not something to worry about. As to removing material from the spring I don't have a clue, so someone else will have to chime in on that.

dave

[T*O*F]

Cutting into the barrel channel is not too unusual when inletting a lock

The problem with that logic is that there's a barrel in the barrel channel and the spring is gonna hit it.  Now what?

[KLMoors]

I've had to take some off of a main spring a couple of times. Hasn't caused any problems.  Make sure you do nice smooth work - no gouges in the spring, etc.  Also, if you use your grinder, don't get it too hot.

[jerrywh]

  For the spring to hit the barrel something else is probably out of position. Even with your combination the spring should not hit the barrel.  Lets see some photos of the lock and the cavity with the barrel in place. Did you buy that lock from Chambers? Is the lock too high in the stock? Going into the barrel channel is more normal than not. Need t osee it.

[E.vonAschwege]

Happens all the time if you're making something Lehigh/Bucks/Eastern Berks - don't grind away width from the spring, you can instead file/grind a bevel on the top edge.  Don't take too much off, give yourself enough of a flat to grab the spring with a spring vise.  Have a photo we can see? 
-Eric

[Acer Saccharum]

I've seen antique guns with pockets chiseled out of the barrel (gulp) for the mainspring.

See if you can bevel the top edge of the spring to fit under the barrel. As Eric said, make sure you still have enough to get hold of with the spring vise.

Tom

[David R. Pennington]

Larger lock > smaller barrel = mainspring hits barrel. File just enough off top corner of spring to clear barrel. Should be ok. Most of work is done by lower leaf of spring.

[sweed]

"I've seen antique guns with pockets chiseled out of the barrel (gulp) for the mainspring."

Total novice here, but would it not be safer to gouge out a small pocket in the huge barrel than to mess with the relatively small and precise spring? Seems more could go wrong filin on a spring! 

[Mark Elliott]

I seem to make really slim and tight little guns where the inside of the stock looks like swiss cheese,  not unlike most of the originals I have seen.   The mainspring intrudes into the barrel most of the time.   Usually a bevel on the top leg of the mainspring takes care of matters.   I never had reason to think that was any sort of problem.   I also don't have a problem taking a little metal out the breech of a heavy barrel.    I usually file a notch for the front lock nail.

[flehto]

On the very slim Bucks County  LRs, I grind a chamfer on the top of the leaf.....do it to all rifles of this style and many slim Lancasters. The lock is mounted higher than the bore center, so there's always interference.  Never removed steel from the bbl because grinding the spring is so easy.....Fred

[P.W.Berkuta]

On the very slim Bucks County  LRs, I grind a chamfer on the top of the leaf.....do it to all rifles of this style and many slim Lancasters. The lock is mounted higher than the bore center, so there's always interference.  Never removed steel from the bbl because grinding the spring is so easy.....Fred

+1 on this answer. I will have a very small opening between the lock mortise where the spring sits & the barrel channel without the upper spring arm  touching the barrel when things go right. When they don't then a bit of "upper spring arm grinding" is in order . As others have said the lower spring arm & around the bend does most of the work.

[jerrywh]

 The chambers springs are already chamfered on top if I remember correctly. I don't like to file on springs, I would rather take off of the barrel some. Filing springs is OK if you do it right. That would be a last resort for me but what do I know.  I did a lot of C weight barrels with chambers locks and never had a problem? 

[bob in the woods]

I've "fixed" /replaced a couple of springs where the builders were a bit too enthusiastic in removing spring material.
Sometimes I've had to slightly relieve a barrel edge/corner to accommodate a spring, but not usually. I do make a drawing first, so most of this is worked out on paper before chisel hits wood     

[flehto]

I use a bench grinder to grind a chamfer on the top leaf.....but then stone it smooth.  Never had any complaints due to breakage.......Fred

[Stophel]

I find it's almost guaranteed for the spring to break into the barrel channel (or get SO close that the wood is less than paper thin, and it simply busts through) when using a Siler lock with its T H I N bolster.  I don't like it, but there it is.  If the spring actually hits the barrel, take a big file and gouge a big notch in the barrel to clear it.  Not a big deal.

[Blacksmoke]

Draken: Grinding off part of the mainspring or notching the barrel breech is kind of a"mickey mouse" way to solve the problem of the lock bolster not being thick enough.  I usually add material to the bolster of the lock to kick the lock farther out away from the barrel.  You can silver solder , soft solder or micro weld a shim to the bolster which will correct the problem.     Hugh Toenjes

[little joe]

Draken: Grinding off part of the mainspring or notching the barrel breech is kind of a"mickey mouse" way to solve the problem of the lock bolster not being thick enough.  I usually add material to the bolster of the lock to kick the lock farther out away from the barrel.  You can silver solder , soft solder or micro weld a shim to the bolster which will correct the problem.     Hugh Toenjes

     How do you widen  the frizzen?

[Hudnut]

I have a Wilkinson 16 bore shotgun made in 1822.  It is designed so that the frizzen is clear of the side of the barrel.  The lockplate bolster has an extension upwards; this fits against the barrel, and the frizzen is closely fitted to the extension.  There is a hole through the extension to expose the touchhole.  Didn't even notice how the lock was made until the first time I removed the lock.
This isn't anything to do with the mainspring clearing the barrel; this is a sophisticated English best "waterproof" flint lock.  But it would be a solution to a too thin bolster.

[Blacksmoke]

Little Joe,  Obviously you have to widen the pan cover as well -  this can be done again by soldering or micro welding additional material onto it.   Here the trick is to heat sink the striking surface of the frizzen so as not to anneal it.   I have done lots of these - it will give your gun the proper width across the lock panels and the wrist, otherwise the gun can look "slab sided" .      Hugh Toenjes

[jerrywh]

Just to analyze the problem, take the barrel out of the stock and hold the lock up against the barrel in the proper position. This will tell you exactly where or if there is a real problem.

[Mark Elliott]

Just to analyze the problem, take the barrel out of the stock and hold the lock up against the barrel in the proper position. This will tell you exactly where or if there is a real problem.

This is probably the best "first step" right answer.   I actually do this during layout to see if I need to bevel the top leaf of the main spring before I even make the first cut in the stock.   There is no way I can think of that beveling the top leaf of the spring could cause a problem, at least,  if you polish it off lengthwise.   I always use a belt sander for such "adjustments" to already heat treated parts.   Even an 80 grit silicon carbide belt will leave a nice polished surface.    By the way,  my 72" x 2" knife makers belt sander from Grizzly was one of the best tool purchases I ever made.    I use it all the the time. 

[mark esterly]

 I did that when I first read this thread as I'm planning on using a large siler with rice's squirrel barrel.  fortunately all is good and I'm thankful for this thread being before inletting.

[ShutEyeHunter]

i had to chamfer the spring on my current re-locking of an old rifle. I was concerned about a crack starting at a surface defect so I polished it to 1500 grit. Also bought a spare spring just in case