doublegunshop.com - home
Posted By: Nitrah V springs wear? - 08/23/22 04:17 PM
An engineer friend and I were discussing using snap caps in our doubles to relax the main springs when not in use. His view is to Not use snap caps and relax the springs as it is just one more cycle. He feels leaving them compressed does not shorten their life but the actual use, compressing and firing the gun is what wears them out. Is there a right answer?
Posted By: Mark II Re: V springs wear? - 08/23/22 05:32 PM
There are x number of cycles in any spring. "Relaxing"The spring uses up a cycle. Think about bending a wire back and forth until it breaks is an example. The wire isn't heat treated so it has fewer cycles until it breaks. If the maker of the spring gets the heat treat right and removes stress risers by proper polishing the spring wil have more cycles built in. But they all have a finite number of cycles.
Posted By: LeFusil Re: V springs wear? - 08/23/22 06:02 PM
Originally Posted by Nitrah
An engineer friend and I were discussing using snap caps in our doubles to relax the main springs when not in use. His view is to Not use snap caps and relax the springs as it is just one more cycle. He feels leaving them compressed does not shorten their life but the actual use, compressing and firing the gun is what wears them out. Is there a right answer?

Your engineer friend is correct.
Posted By: Drew Hause Re: V springs wear? - 08/23/22 06:29 PM
Hunter Arms would agree also; the back of post-1920s hand tag
"We advise leaving the gun cocked at all times."

[Linked Image from photos.smugmug.com]
Posted By: keith Re: V springs wear? - 08/24/22 09:21 AM
Despite the general consensus here, I will continue to store my guns with their mainsprings in an uncompressed state.

It is well known that springs under compression lose strength over extended periods of time. Gun magazine springs become weaker when left fully loaded, and may begin to cause feeding problems. Leaf and coil springs in vehicle suspensions definitely begin to sag over time. Valve springs in engines stored for long periods will show a measureable difference in uncompressed height, and the eventual loss of strength can lead to valve "float" at high rpms.

https://idcspring.com/spring-lose-tension-when-compressed/

None of my guns is likely to have spring failure because I have fired them the tens of thousands of times required to exceed the maximum average number of compression/extension cycles before failure. For almost all of us, the greatest threat to our springs is incorrect polishing and tempering during manufacture (generally beyond our control), and stress risers that occur due to corrosion. In other words, a rusty spring is more likely to break than a spring with a clean polished surface. I'm pretty sure that a real metallurgist who knows a bit about springs and heat treatment would agree.
Posted By: Drew Hause Re: V springs wear? - 08/25/22 04:53 PM
By a metallurgical engineer from one of the frequent thread on Trapshooter.com

All ferrous metals, like springs, will "take a set" over time, and all ferrous metals. like springs, wear due to being "cycled."
However, the "take a set" takes lots of time, many years, and is enhanced if the metal is at high temperature (which gun springs, generally are not.)
So, you have to ask yourself, is it more damaging to the spring to "cycle it" one more time to de-tension it (and remember, it is STILL under tension even if you let the hammer down) or is it more damaging to leave it under tension.
For gun springs, especially if you replace them periodically like you should, I am pretty sure the answer is, it doesn't make a darn bit of difference.

On the same thread it was stated that both Beretta and Perazzi, and made in USA Kolar, recommend using snap caps.

Another engineer on the same thread
As an engineer I look at the Perazzi spring and question the extremely small radius at the corner. The stress concentration must be very high near the corner. I also wonder how the pin is attached. I think that it is welded which can do interesting things locally to the spring metal. Sometimes that local heat can help relieve manufacturing stress, sometimes it can really screw things up. Again, without knowing what manufacturing processes are used, I would just think that increasing that bend radius would greatly expand the useful life of the spring. Marcello Guliani's version of the spring must have a longer working life because of the way he rounded that corner. Once I run out of factory Perazzi springs I will switch brands.
What we do know is that it is very easy to either drop the hammers on a snap cap or a penny, or pull the trigger assy out and drop the hammers manually. Why would you even risk shortening the spring life by leaving them cocked?
For those with coil springs, they don't seem to be as sensitive to breakage, but again, why shorten the life of the spring when you can drop the hammers so easily?
Posted By: Run With The Fox Re: V springs wear? - 08/25/22 05:08 PM
I currently have 3 12 gauge L.C. Smiths- which I shoot rather often- I use snap caps in them, to relax tension on the V-springs, and as far as the ejectors are concerned, having coil springs, those springs are under tension until the gun opened, then they "relax" when they act on the ejectors hammers to expel the snap cap, or fired shell casing. But I do not use them in my older (1940 era) 12 gauge M21--never had an issue with broken springs either. RWTF
Posted By: Drew Hause Re: V springs wear? - 08/25/22 05:14 PM
c. 1900 Parker hang tags
"We recommend snapping hammers down (BTW without a snap cap) when put away for great length of time. (It takes tension off the springs.)"
Posted By: Parabola Re: V springs wear? - 08/25/22 05:19 PM
Is there any truth in the theory that dropping the hammer without a snap cap produces avoidable stresses on the nose of the firing pin?
Posted By: dblgnfix Re: V springs wear? - 08/25/22 05:19 PM
As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.
Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.
Posted By: Geo. Newbern Re: V springs wear? - 08/25/22 06:35 PM
My understanding has always been that a spring doesn't know or care whether it is under tension or not. I've been wrong about lots of other things though...Geo
Posted By: LeFusil Re: V springs wear? - 08/25/22 06:39 PM
Originally Posted by dblgnfix
As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.
Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.


Exactly. And if one is familiar with taking apart actions, you’ll understand that the springs are ALWAYS under some tension regardless if they’re compressed from being cocked, or at “rest” after being fired. This is why you need to compress springs when you remove them from the action. On boxlocks, the mainsprings are compressed even with the hammers/tumblers in the fired position. They need to be compressed to remove the hammers/tumblers, if there was zero tension, the hammers would just fall out when you remove the hammer wire!!! Same with the mainsprings on a hammergun/sidelock. These springs are never not under some sort of tension. Same goes for top lever springs, you compress them to put them in or take them out of their slot, and they are never not under tension.
I’m curious if most people who have ejector guns know that when they use snap caps to lower the tumblers that their ejector springs remained cocked and if they also release the tension on the ejector springs manually and then recock them before assembling the gun?
Posted By: keith Re: V springs wear? - 08/26/22 03:49 AM
Originally Posted by dblgnfix
As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.

Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.

An Engineer should not be making rash statements such as the sentences above that I highlighted in Bold Red Type.

First, I don't see how you could be certain that these guns have been "left cocked for decades". They could well have been cocked by your customers just prior to bringing them to you. More importantly, you could not accurately state that the springs in guns that are over 100 years old when you disassemble and clean them are "just as good as when they were made over 100 years ago." You would have to know how much force it took to compress them when they were made, and also know the exact measurement of their uncompressed size versus that same dimension today. Anything else is mere opinion, and engineers should be dealing with measurable absolutes... not opinions.

I am well aware that the springs installed in guns are normally under partial compression. I am also aware that springs tend to fail when they are under full compression. They are also more likely to take a set when left under full compression for extended periods. Gunsmiths and gunmakers make and sell replacement springs simply because they fail due to breakage or becoming too weak to reliably function. Like most things, they are more likely to fail when subjected to maximum stress, not from being kept in a relaxed or semi-compressed state. It doesn't matter if we are dealing with coil springs, V springs, leaf springs, torsion springs, or springs in a Grandfather's clock.

A couple other things are worth mentioning, I think. We have all seen those very high quality Best Guns that are often housed in prestigious Makers' cases, complete with accessories such as turn-screws, oil bottles, cleaning rods, and snap caps. Now why would these fine and respected gunmakers include SNAP CAPS if it was advisable to simply store their guns in a cocked state? In addition, we are all familiar with percussion and centerfire hammerguns, flintlock fowlers, flintlock rifles, revolvers, lever action and single shot exposed hammer rifles. Virtually nobody stores or leaves these firearms in a cocked state.

And virtually nobody is anal enough to worry that lowering those hammers and cocks is going to diminish the life of their mainsprings.
Posted By: bushveld Re: V springs wear? - 08/28/22 08:25 PM
Originally Posted by dblgnfix
As an engineer myself, I agree with your engineer friend. As a restorer of double guns and maker of springs, I can add this. I see many guns that have been sitting unused
and left cocked for decades. When I remove the parts, clean and then reassemble, the springs are just as good as when they were made over 100 years ago in most cases.
Also consider this, most people at the turn of the century didn't use their guns any where near as often as we do today, with clay shooting and all, I would wager most were all kept in the
cocked position, when put away.

Sir;

Your comments about observing the conditions of V springs that were made in past centuries brought to mind the observations that I have made on old classic V springs especially side lock mainsprings by the lock makers decades ago and the one thing that I immediately look at on a mainspring to judge the merits of the original spring maker. And that is when the mainspring is in full cocked compression is there significant clearance between the legs of the mainspring so that the mainspring legs do not touch each or and more importantly not bind against each other--at any time, even over cocked to maximum. Then secondly when I have the mainspring in my hand look to see how well the polish of the legs of the spring was done on the inside of the legs--down into the "far reaches of the u-bend" of the spring that had to be polished before the spring was heated and formed into a V. The old spring makers also knew how to form the legs of the spring in the correct taper to ensure long life--creating " a spring energy battery". This tapering of the spring legs to prevent undue stress points along it's length to maximize energy and create long life of the spring and at the same time minimize size might just be called an "art", with just a little science and "engineering" added to the elixer. But of course since you are a spring maker I am just reviewing what you already know.

Kindest Regards;
Stephen Howell
Posted By: ClapperZapper Re: V springs wear? - 08/30/22 03:05 PM
Do any of you guys remember the article in shooting sportsman about the making of leaf springs? I think it was the issue that was introducing Jeffery when they moved to Paso Robles.

The discussion was how much space should be allowed between the limbs when they are fully compressed, the radius requirement at the end of the slot, the surface finish, the tapering, and all the minutia of making a beautiful spring that lasts for centuries.

Am IThe only person that remembers that article?
Posted By: Drew Hause Re: V springs wear? - 08/30/22 03:11 PM
Thanks for the reminder
https://shootingsportsman.com/springs/
"a spring under compression invariably will take a degree of bend or set"

Jack Rowe Part 1



Part 2



Part 3

Posted By: Drew Hause Re: V springs wear? - 08/30/22 03:20 PM
Brownells
https://www.brownells.com/aspx/learn/learndetail.aspx?lid=12601

Midway also with Jack Rowe
https://shotgunreport.com/2015/06/11/british-sxs-shotguns-making-a-leaf-spring/

Posted By: ClapperZapper Re: V springs wear? - 08/30/22 03:31 PM
Not the one.

The article was about the aerospace tolerances used for the leaf springs that went into the Jeffrey double rifles when they were being made in Paso Robles.
Posted By: James Flynn Re: V springs wear? - 08/30/22 08:56 PM
If gunmakers don't want their springs set to rest, then why do they provide snap caps and why do Purdy mainsprings go to rest when one removes the barrels?

That being said, I have worked on thousands of V spring guns, most were left cocked and all but a very few functioned perfectly. Many an antique comes into my shop and aside from hammer guns, most are cocked and they work well. If a spring is made from proper steel, the limbs tapered and parallel, no nicks left anywhere and polished properly, then heat treated correctly, they will function for many decades. It must also be mentioned that flint and percussion period springs did not have the more consistent quality steel of the mid nineteenth century, but they performed well. One never knows if there might be an inclusion in the steel.

The cases where I see broken springs is commonly in Spanish guns. The springs are poorly shaped with horrible taper but despite that most of them work.
Posted By: John E Re: V springs wear? - 09/01/22 02:37 PM
Looking beyond the "springs". If the gun is left in the cocked state, the sears and sear pins are left under a heavy sustained load upon rather small bearing surfaces. If the parts are well made and fitted they do not seem to give an issue, yet the concern is still there.
Posted By: Nitrah Re: V springs wear? - 09/01/22 03:48 PM
I appreciate everyone's feedback. I have snap caps for most of my guns and was using them and then wondered about the wisdom of it. Based on the infrequency of their use in my guns I will accept the additional wear on the springs especially for guns not used as much.
Posted By: BrentD, Prof Re: V springs wear? - 09/01/22 03:58 PM
Instead of snap caps, you can slide a wooden dowel down the barrel, then fire the gun while holding it vertically so the pins hit and lift the dowel relaving some if the stress.

Saves you from buying dozens of sets of caps.
Posted By: Karl Graebner Re: V springs wear? - 09/01/22 06:46 PM
Nitrah,
I usually let the firing pins down on a horn block, then assemble the gun with the springs relaxed. It's worked fine for me.
Karl
© The DoubleGun BBS @ doublegunshop.com