Duane Thomas Posted July 16, 2001 Share Posted July 16, 2001 Through the Enosverse Library System, Bill Schwab just sent me Matt Burkett's book. Thanks, Bill! There's some very interesting stuff in here. Matt makes a recommendation I'd never heard before, regards recoil springs: "Most recoil springs are not properly fit to the gun and should be replaced every 2,000 to 3,000 rounds. Take the recoil system out of the gun. Fully compress the spring guide against the guide rod head. If the guide doesn't compress completely, clip the end until it does. If the spring cap doesn't touch the guide rod head, the spring is being crushed when the slide cycles. Cutting the spring to the proper length will help with functioning and increase spring life." Anybody have any thoughts on this? How would this affect the proper weight of recoil spring, if at all? Link to comment Share on other sites More sharing options...
Chriss Grube Posted July 16, 2001 Share Posted July 16, 2001 I'm not sure how it effects the weight of the spring but it works. EGW does the same thing when they build a gun. Mine works without any problems. I use a 11 lb. spring to start and clip it to fit. I don't think there is a PROPER spring weight. I think it goes by the gun and what load you are shooting. I use the lightest spring I can get to function 100% if it's to light the gun won't function then switch to the next heavier spring. Link to comment Share on other sites More sharing options...
Rich Bagoly Posted July 16, 2001 Share Posted July 16, 2001 This thread touches on checking the spring. http://www.brianenos.com/cgi-bin/ikonboard...=3&topic=23 Cutting the spring will raise the spring rate (make it stiffer), and lower the weight (how we measure recoil springs?). Use the spring that works when fit. Mine is a 12.5# with 4 coils cut off. Link to comment Share on other sites More sharing options...
Duane Thomas Posted July 17, 2001 Author Share Posted July 17, 2001 Let's say I'm running a 15-pound spring to start with. Load is 200-gr. LSWC .45 around 860 fps. Link to comment Share on other sites More sharing options...
Chriss Grube Posted July 17, 2001 Share Posted July 17, 2001 Duane, Sorry aint that easy! Trial and error is about the only way due to differences in guns. Link to comment Share on other sites More sharing options...
Duane Thomas Posted July 17, 2001 Author Share Posted July 17, 2001 Damn. Link to comment Share on other sites More sharing options...
IPSC Supercop Posted July 17, 2001 Share Posted July 17, 2001 Duane, I think there is a range of spring weights you can use, but it depends on how you want your gun to feel in recoil and then again, it has to make the gun function and also not beat it to death. I use an 11lb ISMI recoil spring with my STI 40 with 1 shok buff. However, I shot my Para P13.45 for 130 rounds. It has a standard guide rod, 14lb spring, with 1 shok buff. I shot 130 factory 45 rounds. When I checked the gun after 130 rounds, the shok buff was smashed, split in two pieces and absolutely destroyed. I could not have done that much damage to a shok buff with my dremel tool!! I was amazed at the damage. I immediately put in an 18lb spring and will have to function check to make sure it works with a heavier spring. I didn't realize the 45 was that much more than the 40. Kevin/IPSC Supercop Link to comment Share on other sites More sharing options...
IPSC Supercop Posted July 17, 2001 Share Posted July 17, 2001 Duane, Forgot to add, when I took a class with Todd Jarrett, he explained to us that the recoil spring should be fitted to the gun. He said that when the coils finally touch and bind on each other and the spring can't compress anymore, but the gun is still recoiling because it has not traveled far enough, that extra energy has to and is going to go somewhere. It will go into the gun and parts themselves, quickly battering and wearing them out. Recoil springs must be fitted to the gun. ISMI has the instructions for fitting them on their insert in the package when you buy a recoil spring from them. Kevin/IPSC Supercop Link to comment Share on other sites More sharing options...
Les Snyder Posted July 19, 2001 Share Posted July 19, 2001 I'd like to pass on an old tip from Terry Phelps as to selection of correct spring rate....provided you have selected one that does not spring bind...load one round in the magazine, fire pistol limp wristed, weak hand, and you want the fired cartridge to exit at least 6inches from the ejection port, and have the slide lock back (if that is something you want)...springs weights are determined by the diameter of the spring wire provided the length has not been altered... you can make a spring rate scale out of an old fisherman scale...use a piece of rod with slot in end to fit over hook on scale, thread end for washer and nut, measure compressed length for spring, and installed length (pistol in battery) turn grooves in rod so you will have permanent marks. Place spring on rod, insert recoil plug over spring, rod hooked on scale. Pull recoil plug to compress spring, and make note of both readings, though the compressed reading is the one most utilized. I use a heavy spring in my .45's but I'm probably the last one on Earth to do so... regards Link to comment Share on other sites More sharing options...
Bill Schwab Posted July 19, 2001 Share Posted July 19, 2001 After thinking for awhile about this topic of clipping the recoil spring to fit the gun I decided I'd give it a try. (Thanks for bringing it up Duane, I meant to try it but forgot about it.) I'm currently shooting a 5" single stack 45 with the Cominolli frame saver guide rod, and using 16 lb recoil springs with 170 pf loads. Last night I started clipping a spring, and in order for me to get the spring to where it wasn't fully compressed when pushing the plug towards the guide rod head I had to clip off a lot of the spring...I'm at work and don't have the clippings in front of me but I'd guess I clipped 2+ inches off of the spring. This left the spring only a little longer than the guide rod itself. I then assembled the gun and racked the slide. It felt REAL easy to rack. My fear is that I may beat the snot out of the gun, which ultimately is what this clipping is supposed to prevent. Should I start with a heavier spring and clip to fit? Should I shoot it and see what happens? HELP! Bill Link to comment Share on other sites More sharing options...
Chriss Grube Posted July 19, 2001 Share Posted July 19, 2001 2+ inches seems like a lot! I think mine was something like 4 coils. I guess try it and see you might want to reread the section to make sure you are fitting it right. Something doesn't sound right with the 2+ inches. Link to comment Share on other sites More sharing options...
benos Posted July 19, 2001 Share Posted July 19, 2001 bill, I wouldn't be clipping 2" off of any spring. If you really need to do that, then you are starting with the wrong spring. A couple things. Although most are, the spring rate is not always determined by the wire diameter. For example, the only difference between a Wolfe 13 lb and 14 lb spring is an extra 2 coils (on the 14). Now theory states that when you cut a coil spring's length, it actually gets stronger. To me, even though I believe the theory is correct, in the actual application it doesn't make sense because the 14 lb spring actually makes the slide more difficult to open. I've measured it. Maybe this is it - the spring rate is determined by the pressure the spring applies to a scale over one inch of movement. When in a gun, the spring moves much farther than an inch, so the application of a springs rate may not have anything to do with spring theory (cutting a spring makes it weaker). If "spring theory doesn't make sense, think of it like this - a coil spring is no different from a torsion bar type spring. (A straight piece of metal, fastened or fixed at one end, and attached to a moveable component at the other.) It is just a torsion bar, bent into coils. When you cut a torsion bar's length, it gets stiffer, or stronger. Does any of this theory matter concerning what a particular spring does in a particular gun? I don't think so. So we just use approximations of spring rate and try to get the gun into the ballpark. One more thing. I don't buy the routine that you absolutely have to use these newer type spings. (the ones not made out of piano wire) In theory, the are absolutely better, as they do not take a set like conventional springs do. In practice, I've used the old fashioned Wolfe springs for many years with success. I may replace the spring 2 or 3 times throughout a season. Once it "shoots in," they don't change much. I'm not saying that the new springs aren't better, I'm just saying that they are like synthetic oil - you don't have to have it. be Link to comment Share on other sites More sharing options...
Duane Thomas Posted July 21, 2001 Author Share Posted July 21, 2001 I knew there was something about this theory that bothered me. It's not the "spring guide" i.e. recoil spring plug that hits the flange on the guide rod when the slide is at the end of its recoil stroke - it's the spring tunnel on the underside of the slide. By my measurement, the plug is about 11/16" shorter than the spring tunnel. You "take the recoil system out of the gun" and then clip the end of the spring until you can fully compress the "spring guide" against the "guide rod head" and your slide's recoil spring tunnel is going to beat the living hell out of your Shok Buff and the flange on your recoil spring guide rod every time you fire it. Lest you think I've gotten the terminology screwed up BTW, and "spring guide" wasn't supposed to mean "recoil spring plug," a photo in Matt's book shows the plug pushed all the way down onto the guide rod flange, illustrating the correct way things should be. With the recoil system still IN the gun, I can compress the flange on the guide rod until the Shok Buff contacts the rear of the spring tunnel in the slide, without binding up on the coils of my recoil spring (Wolff 15-pound variable). AAMOF it seems just about perfect. So what's the problem? Link to comment Share on other sites More sharing options...
Bill Schwab Posted July 23, 2001 Share Posted July 23, 2001 Thanks for all the help...I'll have to take another look at it. Bill Link to comment Share on other sites More sharing options...
benos Posted July 23, 2001 Share Posted July 23, 2001 Thanks Duane, We had a similar problem crop up on another post on recoil springs. (I can't remember where it was.) Yes, the only time the spring plug can be used to test spring fit is if, when installed, it meets flush with the end of the spring tunnel on the slide. be Link to comment Share on other sites More sharing options...
benos Posted September 10, 2001 Share Posted September 10, 2001 #Moderation Mode Moved here Link to comment Share on other sites More sharing options...
bountyhunter Posted October 24, 2001 Share Posted October 24, 2001 If you have a full-length guide rod, I don't think any of this would matter? Link to comment Share on other sites More sharing options...
bountyhunter Posted October 24, 2001 Share Posted October 24, 2001 On the subject of springs, I have never heard that a spring gets stronger if you snip some coils off: the remaing spring is unaffected. The spring "weight" in pounds is actually a measure of how much weight it takes to expand or compress the spring a certain distance. In phsics, its assumed linear over a certain range such that: F = k X where F is force, x is distance stretched or compressed and k is the spring constant. As a spring gets compressed to the point the coils are touching, it starts to get non-linear and look "stiffer" to the compressing agent than it did in it's linear region. Because of that, I think all gun's springs operate a bit "variable rate". Anyway, I have trouble believein a spring will get stiffer if you cut it. I would like to know how this could be possible? Link to comment Share on other sites More sharing options...
benos Posted October 26, 2001 Share Posted October 26, 2001 bountyhunter, It's true, as the spring collapses and the coils touch and bind on each other, it does affect the spring rate - it gets stiffer. The remaining spring gets "stiffer" simply because it gets shorter as you cut it. If "spring theory doesn't make sense, think of it like this - a coil spring is no different from a torsion bar type spring (on a car, for instance). (A straight piece of metal, fastened or fixed at one end, and attached to a moveable component at the other. like your car's control arm.) It is just a torsion bar, bent into coils. When you cut a torsion bar's length, it gets stiffer, or stronger. It has to. Imagine a fixed diameter rod or wire, one mile long, clamped in a vice at one end you are twisting on the other with a 1 foot long attached bar for leverage. Now imagine the same situation only the rod or wire is 1 foot long. Which do you thing you would be able to twist easier? Does any of this theory matter concerning what a particular spring does in a particular gun? I don't think so. So we just use approximations of spring rate and try to get the gun into the ballpark. OK, I did pull some of that out of a previous post, as you may have noticed. be Link to comment Share on other sites More sharing options...
Mike Auger Posted November 2, 2001 Share Posted November 2, 2001 Springs are rated either by the force required to compress them ( or stretch) a certain distance, for example the coil springs on you car may need 100 kg to compress them 1 cm, this would be a more or les constant rate. The recoil springs we use are rated for the overall force required to compress them the distance to cycle the slide, ie a 11lb spring will require 11lbs of force to compress it to fully open, with the spring not quite coil bound ( coils pessing against each other). as the spring becomes coil bound it's rate goes up to infinity. You can make a gauge to test recoil springs with a washer held in a vise and a long bolt going through the spring and the washer, a nut and washer put on the end of the bolt, jury rig a ring to the head end of the bolt so you can use a fish scale on it and pull the scale it will give you the weight of the recoil spring just before it gets coil bound. Link to comment Share on other sites More sharing options...
2alpha Posted November 2, 2001 Share Posted November 2, 2001 Brian, no doubt that you are right about springs used in torsion getting stiffer as they get shorter. We all know also that when you cut coils off a recoil spring the gun will cycle easier indicating less spring weight. I've been trying to make sense of this because I'm sure both statements are correct. Could it be that each coil works more or less independently as a torsion spring and so cutting coils reduces the number of torsion springs which lowers the total weight? If you could make each coil smaller in diameter it would stiffen the spring in affect. JJ Link to comment Share on other sites More sharing options...
Jack T Posted February 6, 2002 Share Posted February 6, 2002 Greetings, This is interesting. I have yet to encounter a problem of spring bind with a "properly" designed guide rod plug/slide and stock length recoil spring. If the plug/guide and or slide are not properly machined back to full slide travel then this will present a problem because the spring will be pre-loaded more than the original design specs for the spring. (A shock buff does this too) If you have to remove coils from a properly manufactured recoil spring, (more than 2 in a gun with a full length cycle/action) the actual problem lies elsewhere (in respect to 1911 style slides). Years ago we played with physicaly shortening the cycle of the slide so that it would cycle faster. As fast as the 9X21 would cycle and with an extended ejector the original cycle could be shortened to make it even faster and we had to modify springs for that application because spring bind comes into play (with a stock spring). Actually the springs were custom made because after 5 or more coils are removed from a stock length spring the spring becomes useless. (Edited by Jack T at 7:06 am on Feb. 6, 2002) Link to comment Share on other sites More sharing options...
Jim Anglin Posted April 20, 2002 Share Posted April 20, 2002 So what works with this recoil shortening Jim Link to comment Share on other sites More sharing options...
benos Posted April 22, 2002 Share Posted April 22, 2002 2alpha, I think this might be "it." The reason theory doesn't translate to reality (in this instance) is because the recoil spring must fit into a fixed area, and then is compressed to a fixed another fixed dimension. A spring get stiffer as it compresses because the coils begin to touch against each other, effectively shortening the length of the "torsion bar." So, the more coils present in the fixed distances involved, the quicker the spring rate will increase as the coils begin touching sooner upon compression. In other words, the theoretical rate of the spring (on the bench) may have to nothing to do with the installed rate. Does that make sense? be Link to comment Share on other sites More sharing options...
db4 Posted April 24, 2002 Share Posted April 24, 2002 I think what we're missing here is the effect of spring pre-load: the amount of compression between free length and installed length. This determines how much pressure is exerted with spring installed and slide forward. Quick measure on a 5" Colt shows about 5.6" free and 3.6" installed, or 2" of preload (round numbers). So, an 18 lb/in spring gives us 36# of static preload. If we clip the spring 1", it does get stiffer (and no, I don't know how much) but we lose half the preload length, far an installed pressure of 19 or 20# (1 x whatever the new rate is). Now, at full stroke (about another 2in) our spring pressure is (3" x 19#) 57#, where the full spring was (4" x 18#) 72#! Gotta take spring rate x total compression. The BIG question is...did that make any sense? DVC Link to comment Share on other sites More sharing options...
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