How to measure spring weights

Onward Allusion · February 19, 2017, 02:12 PM

For my semi-autos, I usually swap out the recoil spring & striker (hammer/firing pin) spring for something with a little more weight. The problem is that I lose track of which ones I've swapped and which ones are OEM. Is there a device that measures spring weights? I mean, how is it done?

Oliver Sudden · February 19, 2017, 02:47 PM

Springs are measured by how much it takes to compress or expand a given length. I've only see it done with a tool built for the purpose.

**Aguila Blanca** · February 19, 2017, 03:24 PM

In years past a couple of people on the M1911.org forum have posted photos of spring testers they've built. I made one very similar to one of the ones shown there. Mine is a bit clunky, but it works.

NoSecondBest · February 19, 2017, 04:19 PM

Hint going forward: put them in a ziploc bag and mark the bag with a Sharpie.

Oysterboy · February 19, 2017, 05:33 PM

Color code them with paint.

Pahoo · February 19, 2017, 06:23 PM

Quote:

"]Color code them with paint.

I use to work on instruments and this is the common method. Just a dab of paint on one end, is enough. Just make sure you catalog them. Also, my spring kits come in marked bags. We seldom tested our springs but when we did, they compression spring and use a dial or spring type scale and jig. .....

Be Safe !!!

**Aguila Blanca** · February 19, 2017, 07:42 PM

Here's one of the testers from the M1911.org forum. The other one was much nicer, but I wasn't able to find it on the site.

olddav · February 19, 2017, 08:27 PM

Could you just place it on a digital scale, compress the spring one inch (or any given distance) and compair?

Onward Allusion · February 19, 2017, 08:54 PM

Quote:

Here's one of the testers from the M1911.org forum. The other one was much nicer, but I wasn't able to find it on the site.

Ha! I'd never thought of building one like that. I had been looking at my trigger scale but I couldn't wrap my head around it. Yup, that will work. Time to get tinkering.

As for color coding the springs as I get 'em, yes - will do so moving forward.

**Aguila Blanca** · February 19, 2017, 09:56 PM

Quote:

Originally Posted by olddav

Could you just place it on a digital scale, compress the spring one inch (or any given distance) and compair?

No.

I'll use the 1911, since that's the platform I'm most familiar with, plus that's the one we have spring specs for. We typically say the recoil spring is rated for 16 pounds, but what does that mean? It means it takes 16 pounds of force to compress it to the specified length when the slide is fully retracted. And we know what that length is courtesy of the Ordnance Department blueprints that are available at various places on the Internet.

This tells us that the free length of the spring is 6.55", the compressed length is 1.81", and that at 1.375" it stops being a spring and becomes a slid tube. The strength at the compressed length of 1.81" was specified as 13.55 pounds, +/- .60. (This was for the original M1911 -- the industry has now largely settled in 16 pounds rather than 14 pounds for a standard Government model firing standard-power ammunition.)

If you don't know what length the spring is supposed to be at full compression, you can't measure it's strength even if you have a spring tester.

olddav · February 19, 2017, 10:57 PM

My thought was not to determine the total poundage of the spring but meerily to determine which of the springs were stronger than the others (OEM ver After market). OP lost track of which was which and I assumed that with only two strengths in question then a simple test would be viable. If I am still wrong please take the time to inform me again.

HiBC · February 19, 2017, 10:57 PM

Nice tools are great. A machined fixture,Chatillion force gage,etc,is great!!

But,if the main idea is to sort or check your springs,I'll toss out some "Gitterdone" ideas to work with. I have not used them,but I have thought about this .

You need something to go through the spring as "Guide and drawbar"
It could be a bridge timber spike,or a long bolt (unthreaded for the length of the spring)
It could even be a wooden dowel,sized to slip fit through the spring,with a few inches length protruding.You would need a "head" on it that would compress the spring. Drill for a cross pin ? put a nut or washer or other "stopper" between the cross pin and the spring? A section of cleaning rod,with the threaded ends? Use your imagination.A battery hold down bolt with the hook on the bottom and wing nut on the top would probably work.Wingnut on top,the load or fish scale on the hook.

Then you need a hole in something that this guide rod/drawbar will freely slip through,but the spring will not slip through the hole. The spring stops here!
The drawbar and spring are vertical,above the hole. The "head" feature of the drawbar is on top of the spring,and will compress it if the drawbar is pulled down,from below the hole.

Put a washer in a vise.Or drill a hole in angle iron,hardwood,whatever,and put it in a vise so your drawbar with a spring on it can be stood up vertical through the hole,without the spring going through.Material doesn't matter. You just need a fixed hole in something that the drawbar can be pulled down through it to compress the spring.

Now,to apply a measurable force...

Drill a cross hole through the lower tip of the drawbar. Put an "S" hook in it.Or
use the hook on the battery bolt.You just need some means to attach a downward load to the drawbar.
You can mark the 1.810or any other compressed length on the drawbar,measuring down from the head.

You can hook a bucket to it and pour in water or shot,you can use a fish scale,
Anything that will apply the load on the spring in a measurable way.
You can even work from volume of water and weight per oz. A "2 gallon " spring.

If you have a pencil and a ruler,a reference mark can be made for lengths of compression.

Depending on what you are trying to achieve,you can accurately measure a numeric value,of "16 lbs at 1 in compression" or you can record"My new Wilson 16 lb spring was 2 gallons plus one cup of water with this calibrated bucket when it was new.

Or you can compare 5 springs easily.

Reloadron · February 21, 2017, 12:59 PM

Quote:

My thought was not to determine the total poundage of the spring but meerily to determine which of the springs were stronger than the others (OEM ver After market). OP lost track of which was which and I assumed that with only two strengths in question then a simple test would be viable. If I am still wrong please take the time to inform me again.

My thought is just take a simple fish weighing scale, lay spring out beside a ruler and expand the spring an inch or two and note the pounds of force required for a given distance. Just as a comparison between some springs, this should do just fine.

There is no need to get fancy with compression or tension force or make a special jig.

Ron

olddav · February 21, 2017, 10:41 PM

So I'm not wrong. It's just no one wants to try it. Works for me!

Jeryray · February 22, 2017, 01:24 AM

I have one of the digital scales. It does not read correct, however, took my luggage scale hooked that to the end piece and it a good reference for the springs.

Still could be more accurate.

February 19, 2017, 02:12 PM	#1
Onward Allusion Senior Member Join Date: November 17, 2009 Location: Back in a Non-Free State Posts: 3,133	How to measure spring weights For my semi-autos, I usually swap out the recoil spring & striker (hammer/firing pin) spring for something with a little more weight. The problem is that I lose track of which ones I've swapped and which ones are OEM. Is there a device that measures spring weights? I mean, how is it done? __________________ Simple as ABC . . . Always Be Carrying

February 19, 2017, 08:27 PM	#8
olddav Senior Member Join Date: December 21, 2008 Location: Lower Alabama Posts: 727	Could you just place it on a digital scale, compress the spring one inch (or any given distance) and compair? __________________ Never beat your head against the wall with out a helmet

February 19, 2017, 10:57 PM	#11
olddav Senior Member Join Date: December 21, 2008 Location: Lower Alabama Posts: 727	My thought was not to determine the total poundage of the spring but meerily to determine which of the springs were stronger than the others (OEM ver After market). OP lost track of which was which and I assumed that with only two strengths in question then a simple test would be viable. If I am still wrong please take the time to inform me again. __________________ Never beat your head against the wall with out a helmet

February 19, 2017, 10:57 PM	#12
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	Nice tools are great. A machined fixture,Chatillion force gage,etc,is great!! But,if the main idea is to sort or check your springs,I'll toss out some "Gitterdone" ideas to work with. I have not used them,but I have thought about this . You need something to go through the spring as "Guide and drawbar" It could be a bridge timber spike,or a long bolt (unthreaded for the length of the spring) It could even be a wooden dowel,sized to slip fit through the spring,with a few inches length protruding.You would need a "head" on it that would compress the spring. Drill for a cross pin ? put a nut or washer or other "stopper" between the cross pin and the spring? A section of cleaning rod,with the threaded ends? Use your imagination.A battery hold down bolt with the hook on the bottom and wing nut on the top would probably work.Wingnut on top,the load or fish scale on the hook. Then you need a hole in something that this guide rod/drawbar will freely slip through,but the spring will not slip through the hole. The spring stops here! The drawbar and spring are vertical,above the hole. The "head" feature of the drawbar is on top of the spring,and will compress it if the drawbar is pulled down,from below the hole. Put a washer in a vise.Or drill a hole in angle iron,hardwood,whatever,and put it in a vise so your drawbar with a spring on it can be stood up vertical through the hole,without the spring going through.Material doesn't matter. You just need a fixed hole in something that the drawbar can be pulled down through it to compress the spring. Now,to apply a measurable force... Drill a cross hole through the lower tip of the drawbar. Put an "S" hook in it.Or use the hook on the battery bolt.You just need some means to attach a downward load to the drawbar. You can mark the 1.810or any other compressed length on the drawbar,measuring down from the head. You can hook a bucket to it and pour in water or shot,you can use a fish scale, Anything that will apply the load on the spring in a measurable way. You can even work from volume of water and weight per oz. A "2 gallon " spring. If you have a pencil and a ruler,a reference mark can be made for lengths of compression. Depending on what you are trying to achieve,you can accurately measure a numeric value,of "16 lbs at 1 in compression" or you can record"My new Wilson 16 lb spring was 2 gallons plus one cup of water with this calibrated bucket when it was new. Or you can compare 5 springs easily. Last edited by HiBC; February 19, 2017 at 11:19 PM.

February 21, 2017, 10:41 PM	#14
olddav Senior Member Join Date: December 21, 2008 Location: Lower Alabama Posts: 727	So I'm not wrong. It's just no one wants to try it. Works for me! __________________ Never beat your head against the wall with out a helmet

February 19, 2017, 02:47 PM	#2
Oliver Sudden Senior Member Join Date: January 7, 2017 Location: Colorado Posts: 272	Springs are measured by how much it takes to compress or expand a given length. I've only see it done with a tool built for the purpose.

February 19, 2017, 03:24 PM	#3
Aguila Blanca Staff Join Date: September 25, 2008 Location: CONUS Posts: 18,457	In years past a couple of people on the M1911.org forum have posted photos of spring testers they've built. I made one very similar to one of the ones shown there. Mine is a bit clunky, but it works.

February 19, 2017, 04:19 PM	#4
NoSecondBest Senior Member Join Date: December 7, 2009 Location: Western New York Posts: 2,736	Hint going forward: put them in a ziploc bag and mark the bag with a Sharpie.

February 19, 2017, 05:33 PM	#5
Oysterboy Senior Member Join Date: March 3, 2012 Location: Texas Posts: 970	Color code them with paint.

February 22, 2017, 01:24 AM	#15
Jeryray Senior Member Join Date: December 29, 2016 Location: NY Area Posts: 310	I have one of the digital scales. It does not read correct, however, took my luggage scale hooked that to the end piece and it a good reference for the springs. Still could be more accurate.

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