Airgun Technologies Mainspring Deformation

[Maker's Marksman]

Everyone knows it, some mainsprings are utterly deformed, really bent and the coils compressed. This always seems to occur at the rear end.
I don't quite understand why some airgun models or airgun/spring combinations seem to regularly do that while othes don't. It doesn't seem to be caused by a not perfectly fitting spring guide but (to my suspicion) very probably occur when the spring is near or in fact coilbound when cocked.
For instance the humble and cheap Diana 48 mainspring doesn't droop or get bent in the 52, the 35c and the HW85 neither. Though the spring guide is not perfectly fitting, leaving about 0.7 mm clearance.
But any mainspring I insert into the HW 35 is strongly compressed and bent after some shoots. And the guide fit is tighter.
Does anyone know better?

So spring quailty isn't it most probably, spring guide neither, neither grease sleeve for the 52 has no sleeve at all but the spring remains straight and long.

 

[Sqwirl57]

You want the guides to be a right fit. The top hat should very closely match the piston ID but loose enough to spin freely. The rear guide needs to be snug. The more preload the spring has the looser it will be once everything is installed. A properly sized piston sleeve will help too. A buttoned or nylon ring on the piston sized to the main tube wall will keep the piston straight. All of those parts working together will ensure the spring compresses as straight as possible.

As a final thought, recent Weihrauch springs haven't been the greatest in my experience. I always swap them out for ARH springs and make my own guides and everything else noted above.

 

[Hateful McNasty]

Spring guide I like tight near fight it in tight. Too much preload can cause that kinking looking spring .

With the piston and tube in cocked position measure from the spot in the piston where the spring rests to the other end where the spring and guide washer rests and that your max scragg of a set spring length ( spring compressed to all coils just touching)
Kinda showed in the pa blog

Resizing a mainspring | Blog | Pyramyd AIR

by B.B. Pelletier I recently started writing more reports about the fundamental things that many airgunners would like to know. These are things you don't have to know to shoot an air gun; but if you do know them, they can often help you recognize why your gun does what it does. You also don't

www.pyramydair.com

 

[Bear-of-Grayling]

This is why I prefer a Vortek spring kit. Tight sleeve, spring guide, and very little preload. Nowhere for the spring to take a negative set. I believe the set comes from an imperfection in the metal. When there is room to exploit this imperfection, a bend occurs. Eventually the spring will likely break at this spot.

 

[Mycapt65]

I don't know what causes the deformation. I can say that it's not necessarily a bad thing. While most people and tuners will tell you a spring is bad when it deforms and might be right, the deformation can quiet the rifle. I know this is counter intuitive but how many times have you heard of a springer starting off buzzy and quieting after a few tins of pellets? Many people have experienced this and choose not to tune their guns. It undeniably happens to a lot of springers.

The reason for the buzz reduction is the spring deforms and leans against the guide more. The spring vibrates less with more points of contact. Deformation is often accompanied by reduced power which too reduces felt recoil. I can say this with confidence because I've experienced it with my first two springers. Both my HW30 and 95 started out buzzy and quieted with use. They also broke their OE spring after the first summer of heavy use. The 95 spring was in three pieces and the 30 was broken a few coils from the trigger end. Both were replaced with factory springs. Both became instantly buzzy like new again. After a few tins they quieted up as before. I found these forums and they got me interested in kitting the guns so I did. When I disassembled them both springs were noticeably deformed but not broken. I installed Vortek PG2 kits in them and there was an improvement that spoiled me. I kit all my guns now.

Not all springs will deform but all eventually break. Some faster than others due to materials, gun design and user abuse. Dry firing and heavy pellets both shorten spring life. I've replaced several springs in Weihrauchs and most of them break at the trigger end first. It's been explained this has something to due with shock wave resonance. Whatever the reasoning it holds true that the trigger end usually breaks first. I know I haven't really answered the OP but I thought some of you might find this information interesting or useful in answering the OP.

Be well
Ron

 

[Maker's Marksman]

True, such deformation might reduce spring vibrations. I try to optially guide my springs. The HW 80 and 35 don't come with a proper guide neither the new plastic (which broke into pieces after short use) nor the old way too short, way too slim windmill based steel ones do properly.
So I make my own guides for them. (15 mm od) The titan No.2 is in the 80 the No. 4 in the 35, both springs of same steel and dimensions just the No. 4 has a few coils less. But the 80 spring keeps its length and stays straight while the 35 spring shrinks by 3 cm and is utterly deformed. As were the former genuine 35 springs.
The Diana 52 spring I inserted with the genuine plastic guide into the 52, the 35c and the HW 85 and it keeps its shape and energy in any of them which puzzles me. I don't think that the steel of that 12€ spring is better than the titan steel. And the 52 spring vibrates a lot for I haven't grease sleeved the piston. But nevertheless it doesn't seem to droop at all.
While the 35 doesn't vibrate at all (from the very beginning) but looses its power within the first 100 cycles.
That's what I don't quite understand. Ok, the 35 shoots fine at 14.5 ftlb but I know in the beginning it was higher power (about 16 ftb) and I know about the huge spring deformation. If I didn't knwow I was fine. Just want this gun to keep its spring like the other guns.

 

[Hateful McNasty]

All my stuff shoots hard and fast with I fresh new spring , but after x-amount of shot it settles in to it's " true" power ..
Even presetting the spring you still get some of that.. my nylon hw guides been in several springs and can go a few more .. suprizing durable...

 

[Mycapt65]

All your guns somehow defy the normal design power limits. I've never seen a HW35 make 14.5 fpe much less 16. At least without combustion enhancement. Are you sure of your energy calculations?

 

[dizzums]

imo they leave them malleable so they dont break .. you take the good with the bad i guess ..

 

[Maker's Marksman]

All your guns somehow defy the normal design power limits. I've never seen a HW35 make 14.5 fpe much less 16. At least without combustion enhancement. Are you sure of your energy calculations?

Not just calculations but chronified, too.
Those 14.5 is @ 0.22, @ 0.177 it is just 12 ftlb. But with the spring in the original state as they are and stay in my other guns it was 16 and 14 ftlb.
I'm always trying to get maximum power out of them and I think 14 ftlb is the minimum power out of a gun of that amount of solid metal to make sense.