Mainspring protrusion

[Mauser06]

I'm working on my first plank build. 

I inlet the lock and lock bolts.  The front bolt skimmed the bottom flat.  I filled a round grove in the flat for the lock bolt clearance. It wasn't protruding much into the barrel channel. 

I noticed the tang still sits a smidge proud of where it was. 

I looked and realized the main spring is protruding into the barrel channel just a smidge. 


I haven't run into this yet...


The lock is a Chamber's Dale Johnson.   


Is it "safe" to file the top edge off the main spring?   I wouldn't have to knock much off of it. I just don't know the do's and don'ts of filing a spring. I don't wanna ruin the spring. It's a pretty beefy spring.   


Wanted to check with you guys before messing anything up. 


Thanx!

[greybeard]

i have done that and no problem.   bob

[flehto]

My Bucks County builds have the mainspring ground to miss the bbl....usually not that much is removed......Fred

[smylee grouch]

I have heard of others doing the same thing and it turned out ok. The experts will chime in but I wonder if grinding in one direction over another would be the best route to go, as in grinding lengthwise instead of crosswise. Just a thought and food for thought.

[Mauser06]

Thanx guys! 

Wanted to check. Like Fred said, I won't need to remove much.  Basically knock the corner off. I should be able to file it and not hit it with a grinder. I'd be afraid of the heat issue on the spring too...it's a beefy spring...just didn't wanna screw things up and figured I better ask.  Learning as I go. 

[Eric Krewson]

I filed the main spring on my first build to clear the barrel, I probably took off too much but later decided to put a new spring back in the lock and see how much I needed to notch the barrel to accommodate the spring. Turns out I had to make a very slight notch on the corner of the flat that amounted to about 1/6". My lock was much faster when I put it back in the condition it was as new.

[smokinbuck]

As for filing a spring. I've never had to do one but have been told to file length wise not across. Fact or fiction, I am not sure.
Mark

[Eric Krewson]

I filed two springs, one was in a Deluxe Siler, the other was an English round face. I draw filed the inside then using progressively finer sandpaper, all the way up to emery cloth, I polished out all the file marks to a mirror surface.

I ended up ditching my filed springs and going back to new springs on both locks. Turns out I had filed the English round face spring as a newbie precaution to stay off the barrel for no reason. The new spring didn't hit the barrel.

The mainsprings on all my locks have scraped on the lock plate when new. Now I take off just enough metal to see a hint of daylight between the spring and plate.

[David Rase]

If the breech of the barrel is big enough, why not remove metal from the lower oblique flat in lieu of filing of the spring.  Just another approach that I have used.
David

[bob in the woods]

I've filed off the corner of one barrel to accommodate a lock spring and it worked out well. I didn't want to mess with the lock. Having said that, I now do all my layout on paper first.  No more surprises 

[Joe S]

The strength of a flat spring is directly proportional to the width. Thus if you narrow it by 10%, it will be 10% weaker.

However, this is not true of the thickness. Spring strength will vary by a cubic function of the thickness, so thinning a spring by 1/2 will result in a spring about 1/8 as strong. Boyers are intimately familiar with this mechanical property of springs.

[Mauser06]

I guess the barrel never even sparked in my mind....I can be pretty simple at times..


Probably the safer way to go.  I'd hate to mess up the lock. 



Bob, you're right...a little better planning would have avoided the issue at all.  Mistakes make for a better gun stocker....as long as the gun stocker learns from those mistakes.

[Mr. Bubbles]

Put a little chamfer on the main spring, and also taper and chamfer your RR.  If it nicks it, it should slide off and not hang up on it.  If your RR hole is really tight. you might even open it up a little in the lower fore stock with a slightly larger bit size, or by wrapping sand paper around the current hole-sized bit and spinning it a little.  I just about never use the field rod anyway.  To me they're largely decorative.

[Mauser06]

Mr bubbles, the top of the main spring is poking into the barrel channel...not the ramrod channel. 

[Mr. Bubbles]

My mistake.  Sorry.  Then you have to make room for it, by either filing the barrel, or the spring, or both.  You mght be able to do neither by making yourself a new spring, deeper rather than wider in the offending area.  I have no experience along those lines to advise you on however.