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Evaluating spring strength


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Thanks RIP.

 

Its important to me because I'm constantly shooting and testing various ammo in:

5" 1911 10mm

Two 6" 1911 in 10mm

Two 5" 1911's in .460 Rowland

 

Various manufacturers offer a wide variation of spring strength and lengths, regardless if barrel/slide length is 5" or  6".

 

..........Widder

 

 

 

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The way it was always explained to me is if you have a 18# 1911 spring and cut it in half it should still take 18# to compress either half , or pretty close , the length is the amount of pre load it has , which can really effect how the gun runs . I used to build 1911 comp guns back when you had to make your own comp , had to play with all kinds of springs to get them to run right, the better the comp works the lighter the spring has to be . Clipping coils off of a coil spring is almost never a good practice 

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20 minutes ago, Widder, SASS #59054 said:

Thanks RIP.

 

Its important to me because I'm constantly shooting and testing various ammo in:

5" 1911 10mm

Two 6" 1911 in 10mm

Two 5" 1911's in .460 Rowland

 

Various manufacturers offer a wide variation of spring strength and lengths, regardless if barrel/slide length is 5" or  6".

 

..........Widder

 

 

 

Been working up a Clark Compensated Long Slide 70 Series on and off for a couple of years.  Even got an "antique" Ernie Hill holster for it.  Like a mirage, so close and yet untouchable.  Not reliable.  Told a guy about the issues and he wants to buy it.  I will try one more batch of loads, and if I can't get it working, pass the problem to a guy who knows about them.

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Normally a compression spring is guaged at a particular force developed  by a particular distance of compression.  So if a spring of given weight is shortened, but still compressed  the same distance it should exert about the same force.  But if a portion of that pull distance it no longer actually compressing the spring, then the real compression distance is lessened, and the force exerted would be proportionally reduced.  

 

added:  The science of spring physics, like screw thread dimensioning, is not uncomplicated.

I have an inch-thick very technical monograph about the physics of coil springs.  I've read it, or tried to, several times.  It is very technical stuff, with a lot of complex math and Calculus.  I understood about a tenth or less of what I read.  There's just no way to simplify the subject.   

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5 hours ago, Widder, SASS #59054 said:

I have a 24# Wilson spring for the 1911.    It has XXXXX coils.

 

Is the spring still rated 24#  when a couple XX's are removed?   

 

..........Widder

 

No, why would it be?

You altered the spring's OAL.

OLG 

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Here is something that might be of interest. I ordered a set of Wilson Combat springs for my 442 J frame. 
8C5F3AA9-2613-4C5B-876F-EF319E3A7F72.thumb.jpeg.41a680db1f14bde53c861963f98097af.jpeg

I do not know for sure but I think the spring on the left is the 13# judging by it’s thickness, but I can’t tell from the photo which is the 14 or the 15 pound spring. They each have 15 coils. 
 

How’s that for adding to the spring confusion?

I actually went into this thinking I could help and that the 14 and 15 pounders would have a different number of coils. 
Maybe it will be obvious after I receive my order next week. 

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9 hours ago, The Original Lumpy Gritz said:

No, why would it be?

You altered the spring's OAL.

OLG 

 

Lumpy,

So, if I cut 1 coil off of a 20 coil spring, does that reduce the spring strength 5%?

 

..........Widder

 

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I would look more into something like this “not saying this is the ideal thing for you situation” 

https://www.gunsprings.com/content/File/Colt Longslide Recoil Instructions.pdf

you can measure the wire diameter of what you have , use the next smallest wire diameter you can find and still maintain the oal length of the spring . I would even be willing to try a longer spring with a reduced rate “as long as it doesn’t coil bind” , before I started clipping coils off of a recoil spring. 
When you start clipping coils and reducing the preload it gives the slide more of a running start , with the calibers you are mentioning I would be worried about the gun beating itself up more than is necessary 

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So lets say that you have a spring that is 8" long, and it takes 24 lbs of pressure to compress the spring 1". That compression is equally applied along the entire length of the spring.... i.e. each coil moves the same amount. Now... let's cut that spring in half (4") and again compress it 1". Each coil must now compress further than it had to when the spring was 8" long, and it take more than 24lbs to compress the spring 1" because the required pressure to squeeze each coil down increases the more you squeeze (compress) it. The only reason that cutting coils off springs to lighten the action on a gun or the amount of effort to open the SXS, is because it cuts down on the overall amount of compression to the spring due to less "Preload". If you want to do it right, don't rely on cutting coils.... reduce the diameter of the spring. About the only way I know how to do that is really just removing material from the outside of the spring by using a grinder. As more material is removed, the spring resistance become weaker and it becomes easier to compress. Doing it this way also maintains the same amount of "Throw" the spring has. So if you cut a couple coils off the spring, it gets stronger if you intend to compress the spring as much as you did before.... however, if you lessen the amount of compression, the overall effect will be to weaken the spring. That's my story and I'm sticking to it.

 

Snakebite

 

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Snake bite is correct, a shorter spring is a stiffer spring.   An easy way to visualize this is take a yardstick and grab both ends, now gently bend it.  Now grab the middle and one end, try again.  Harder to bend.  It’s a stiffer spring.  
 

coil springs are just a leaf spring wound into a coil for space reasons.  Springs are usually rated in force per distance compressed.  Ie ft/lb or kg/mm or in/lb.  for a 10lb/in spring if it’s compressed 1”, you get 10 lbs of force.  If 2”, 20lbs.  When you cut it shorter the rate becomes stiffer.   Say you have a spring that is 10” long and it’s 10lb/in with 1” of preload (9”) At rest the force is 10lbs, at 8” length it’s 20 lbs.  now we cut that spring to 9.5” and the rate is now 20lbs/in (not realistic, but easy math),  at the same 9” length it’s 10 lbs of force and then at 8” long it’s 30 lbs of force.   So cutting a spring can reduce initial force, but can actually increase force later in the travel.  
 

to reduce the spring rate, the spring has to be either be longer or thinner.   So more coils for a coil spring or thinner diameter wire.  

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Odd I never thought of that Widder, LOL.

 

Spring is a function of the wire diameter and thickness of the wire itself. Length will have an effect but I've never measured the effect of shorter. Since I have the tooling to do that, I should. (PS; I prefer using a weight rather than a fish spring scale)

 

In a 1911 spring length is necessary to maintain the proper tension all the way forward or the spring runs out of "oomph" as the slide nears closed. Feeding issues and/or failing to completely lock into battery happen.

 

I generally change recoil springs every 3000 or so rounds in a 1911. (glock springs go a bit futher but I digress) If you take a new 1911 spring, measure it. Go to range. Shoot some. Say, somewhere between 100 and 1000 rounds. Measure. About half inch. A spring that's been in service a while will be almost an inch shorter. (I prolly got a few of these in my "junk" boxes so guess what Dubious is gonna do if he finishes all of his chores today, LOL

 

Yeah, you can probably get away with shorting a spring but remember to keep an eye on function. I prefer to use Wolff reduced springs. Same length, thinner wire. Lasts better.

 

On S&W revolvers. The hammer spring controls hammer, rebound spring controls trigger. They must be balanced or the hammer spring, now being too "fast" for the poky light rebound spring to get the trigger forward, this can negate the internal hammer block safeties. Not good.

 

Yes you can shorten the spring to lighten the pull, but only do much before you must ALSO adjust the hammer spring tension. It is NOT adjusting the screw. The screw itself should be shortened or replace that spring with lighter.

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At present, I'm using and testing Flat Wire springs from WILSON.   These are the recoil springs they recommend for 10mm and .460 Rowland

1911 pistols.

 

One of the reasons I started this thread was because 'somewhere' I had read that round wire recoil springs needed to be 'tuned'

to the pistol it was being used to insure it didn't 'bind'.   ALL this is in reference to the 1911.

If the slide can't completely recoil because the spring binds during its collapse, it was recommended to CUT coils off the spring

until the spring is properly 'lengthen' for compression.

 

There is some valuable info posted above...... Thank you All.

 

..........Widder

 

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Allrighty then. Dubious done got his errands for the day done (or as done as they're gonna get, LOL) Got us some pork shoulder for a buck 29 a pound, didn't get no smoked sausage because they were out (good sale, 2 for 5 bucks) got butter, coffee creamer and some other sundries like a few more NATO fuel cans, found some really cool soldier's manuals for my old MOS 95B along with one for physical security which is otherwise known as Tower Rats to the Military Police community. Found the lens I was looking for my Canon (some dork put it in the Nikon drawer) pulled some weeds, stuff like that. So. On to bidness.

Disclaimer;

Scientific methods were used.

Accuracy guaranteed to reasonable standard. (close enough for gubbermint work, LOL)

No warranties expressed or implied.

Use at your own risk. As always, the Secretary will disavow any knowledge of your actions.

 

I used a new Wolff B 1911 recoil spring. 16lbs, measured 6 3/4", 31 full coils.

Spring was tested in a custom test apparatus using regulation trigger weights of 16 pounds.

Spring compressed to a mean length of 2 1/2" while under full load of 16 pounds.

Fully compressed the spring measured 1  1/2"

Cutting two full coils from the spring resulted in a compressed length of 2 inches. The length of the cut section was 1/2"

Cutting another 1/2" section the spring held 16lbs with a length of 1  1/2"

Please note. The accepted "standard" for the space inside the recoil spring tunnel at maximum rearward slide travel is 1.625 inches. So in theory, you would still have a 16lb spring but it will be shorter. The risk here is it will allow the slide to contact the recoil spring guide. Over time, this will peen the edges of the guide resulting in possible sluggish function. Possibly. It's also hard on the frame and can lead to cracks.

So there ya have it Sports Fans, science in action !!!:P

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20 hours ago, Widder, SASS #59054 said:

At present, I'm using and testing Flat Wire springs from WILSON.   These are the recoil springs they recommend for 10mm and .460 Rowland

1911 pistols.

 

One of the reasons I started this thread was because 'somewhere' I had read that round wire recoil springs needed to be 'tuned'

to the pistol it was being used to insure it didn't 'bind'.   ALL this is in reference to the 1911.

If the slide can't completely recoil because the spring binds during its collapse, it was recommended to CUT coils off the spring

until the spring is properly 'lengthen' for compression.

 

There is some valuable info posted above...... Thank you All.

 

..........Widder

 

No pistol slide should have the travel limited by the spring . Just take the spring out of your pistol, leaving the guide rod/plug in , pull the slide back and take a measurement. Put the spring back in and repeat . The measurement should be the same . I really doubt Wilson would be selling a spring that would bind , unless this is something you’re told to do in the instructions when you purchase it , also round wire springs take up way more length than flat in the same poundage , you should be able to get more spring length/preload with a flat wire spring . I would view them as a improvement in the thumper calibers your dealing with 

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Grinding springs can cause microscopic scratches which become cracks under repeated compression and release. That leads to breakage. The ground portion must be polished to eliminate any flaw which can result in cracking over time. Also bear in mind as a coil spring compresses its outer diameter enlarges very slightly. Not a problem if it is not in a bore of some sort. If it fits closely in a bore, with no compression, it can hang under compression or wear the bore. Any flaw or burr in the bore can scratch the spring bringing us back to broken springs.

My$.02

 

Imis

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When tuning my 1911s I used a bunch of springs of various compression weights. 15# to 23#, I believe. I cannot recall details but I am pretty sure 18# was the magic number…and the exact poundage of the stock spring. :blink:

 

Brownells got my money…

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Widder, make it easy on yourself.  Call sprinco  (where I get all of my 1911 springs, and they are color coded) Tell their their tech guys what you have and they will tell you the correct spring (and sell it to you as their springs are a bit different from Wolf etc. 

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