Irregular Pitch Spring Installation
 

Does it matter which direction I install my irregular pitch spring? I have a basic mechanical knowledge of the mechbox workings and I can't think of a reason it would matter.

Thanks in advance. (I did a search and could not find anything)

Install it with the more compressed coils at the spring guide end. Otherwise you'll get lower fps than expected.

Thanks.

I have seen this error more than once. It's been one of the first things I check by default when I open a gearbox. I had another case on the last gun I worked on.

Maybe this should be sticky'd?

I've seen it a few times as well. Heck, last year when Kokanee got his M14, he asked me a bunch of questions about upgrades and that was one of them.

Close call for me, too, if it weren't for this thread. You'd think Prom would, I don't know, tell us these things.

Hate to plug my own thread but:

Could someone make this a sticky thread or move the content to a sticky thread? I keep forgetting the info in this thread.

Thanks

You mean Prometheus? What about any of the other spring makers? It should be documentation that comes with all springs.

ANY non-linear pitch spring, regardless of maker, regardless of airsoft gun, including bolt action springs. Tighter wound coils at the rear always.

I just was wondering what he meant by "Prom". I know about the coils thing, I was just saying they should include documentation for people that don't know. But maybe people that don't know shouldn't be taking apart an AEG!

i've heard the opposite
http://www.airsoftcanada.com/showthr...tightly+coiled
"Make sure the tightly coiled end of the spring goes towards the piston."
i messed it up once and i was getting about 280 fps out of a 350 fps spring

Sorry, that was incorrectly stated. I've corrected it.

I would've thought my more recent posts regarding the topic would have come up before that post...

I got a 30fps drop by putting the tighter end into the piston before.

I DO agree, there should be a simple diagram on the packaging to show the proper orientation.

My PDI 150% package actually has a small installation diagram on it.. now if only they made their springs as good as their packaging.

That's not the best example because, a PDI is like a box of chocolate... you never know you are going to get.

LOL this quote is amazing. I chuckled out loud at work... nicely said. :D

And that is why the spring is still in the box! I keep it around for that diagram haha

Agreed, words to live by! I think nthe biggest problem is the PDI 150% springs largely come in lengths ranging from 6 3/8" to 7" long. How's that for consistancy? :confused:

I was thinking more that a PDI spring was more like the ugly girl in a bar at last call. You know you shouldnt, but the more you look at her, the better she looks and in the end, your just gona stick it in anyways.

....

Another awesome quote from the awesome quote factory that is TokyoSeven :D

Don't forget to double bag it, and use rubber gloves.

And fire.

Is that in regards to the spring or picking up a gal at last call? Usually for the latter I just recommend a large paper bag and a tench coat with a hole in the back.

yeah my PDI 120% was shooting higher than a PDI 130 should have lol

Just installed a Systema bearing spring guide and M120 spring into my AUG using the "coils go towards the spring guide" advice. :D

I am never helping you do that again. I think I broke a nail.
Lets work on our crap canon project later.

Yeah it definitely takes more than 2 hands. It's a bit difficult.

Is there a difference between a normal spring and a "Irregular-Pitch Taper Spring"? or is it the same thing? :confused:
http://shop.ehobbyasia.com/systema-i...ude-psg-1.html

And is there a such thing as quality with a spring or could I buy this?
http://shop.ehobbyasia.com/shs-m110-...de-spring.html

Id rather go with a 110 spring but I'll have to buy some "no name" one from this website.... bad idea? Im buying a battery so I thought I could save shipping and buy a spring as well!

There's linear (regular) and non-linear (irregular) springs. Regular springs have all the coils spaced out evenly. Non-linear have sets of coils bunched closer and further apart. Some have a tight pack of coils at one end...some at both ends...some in the middle...and combos of all that.

The purpose is to impart a different power curve as the spring is untensioned. Different power peaks, different timing of peaks, etc...

As a rule of thumb...when installing a non-linear spring, install the tightest pack of coils towards the rear (i.e. spring guide end) for the most power.

All springs are not created equally. IMHO it's worth going with a recognized brand.

Sorry about bringing back an old thread (but it shows I did search ;)).

I have a King Arms M4 which I needed to downgrade to below 400 fps. I was told that I could install a M120 spring (non-linear pitch) backwards, with the tigher packed coils to the front. This would effectively give me the same fps as a M110 spring (which the store didn't have in stock). So, I tried it. With the M120 spring (ICS brand) installed correctly, the gun shot at 420-430 fps. Reversed the spring and it still shot at the same 420-430 fps. So, any ideas why my experience differs from the information that I was given and also the info that I found on this thread?

all springs are different depend on the coils.

Do you mean that for some irregular pitched spring, the orientation does not matter (obviously, that is my experience with the ICS M120 spring)?

But, does anybody know why?

I've attached a picture of my spring.

I have replicated your results before. S110+ irregular spring, flipped one way, 403-407fps. Flipped the other way, 403-407fps.

I think this topic needs more investigation.

Hardcore graveyard.

Tighter coils on a non-linear STILL go to the back right? Results are so varied in this thread and I'm a cell and don't want to search anymore :(

Edit: I also had the same results as Maciek - Modify s110 flipped both ways 363fps (using silent head set)

Side note: I just cracked open a v2 box I'm working on because I noticed metal shreds/dust around the spring guide - tighter coils were to the guide, the mad bull red guide is grinded to shit, same with the busy end of the spring - gears,piston remain in perfect shape - what the shit caused this??

yes, to the spring guide, always to the spring guide

A guy here comes up with the conclusion that tight coils should be towards piston. I personally don't think it would matter because if you push on the spring from either side the spring should compress and decompress the same way.

um. guys a retard.
Science counts for nothing when the actual physical evidence has shown MANY (and I mean dozens of examples just on the forums here) that you get higher fps when the tight coils are to the spring guide.

I don't understand the science of it myself, like not even a little bit. But the fact is, tighter coils on spring guide = higher fps. Fact.

I also hate these guys that use lots of theoretical science to try and disprove actual fact. If your science is telling you something that factually happened is incorrect, then it's the science that is incorrect lol

Lots of people here didn't understand BB physics, the science geeks would explain it with very basic physics. Problem was, those physics were incorrect because they didn't factor in enough information. They were missing too many variables and thus their conclusions were always incorrect.

The scientific method, in it's pure form, should in such a situation indicate an incorrect hypothesis. The human element (ie. hubris) really derails this supposedly unbiased process. Reference Galileo or Hubble for similar examples; both were denounced by their contemporaries for suggesting observable phenomenon contradicted accepted theories.

Close coils go in the area where the highest stress is and where the least movement is.

The close coil end is heavier so if you put it on the piston end you're adding mass that has to be moved with every cycle.

Think of it as a valve spring in an engine vs. a coil sprung shock. It might start to make more sense that way.

Whatever the explanations are I've found no difference in having the coils the wrong way.

If your observations are that it doesn't make a difference...that's fine.

TBH since over a year ago I've stopped working on setups so I'm open to the possibility that things may have changed...particularly with the tempering of springs.

Prior to that litterally hundreds of AEGs went through my hands and while certainly the work on them all didn't involve flipping a spring and chrony'ing the difference I would, and did, definitively say that I observed a difference in nonlinear springs. Definitely some brands did not differ as much as others for whatever particular reasons.

In truth I think that finding a cause for a 5fps difference in one AEG setup versus another is a bit pointless. Typically you set things up as best as you can and then get what you get. There are rough "rules" and "guidelines" about what combo will result in what...but there are plenty of variables and exceptions that buck those.

One of the examples I'd put up would be the 550+ fps w/0.20 AK Spetznas (CYMA of all brands) whose only modification was a reshim, muck out the worst of the grease and swap to a M120 spring. Shouldn't have been possible...but from the multiple chronies, cycling, sound and damage to the shooting box it was definitely beyond hard hitting. I ended up doing 3-4 spring swaps to finally get it down to just over 400fps. Each lower power spring did drop the FPS...but not by the "typical" amounts or anything close to it. I still don't really know why it shot so "well"...but the guys said it was a beast in the field. Should have kept it....