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Slavia · Moderator

Spring compressors are pretty simple. It's not so much a question of brute force as keeping everything under control as the spring relaxes slowly.

http://www.americanairgunhunter.com/sprngcompres.html
http://home.comcast.net/~pelletgunn/jig.htm
http://www.geocities.com/ftshooter2000/photopage2.html
http://www.airguntoys.com/tuna.htm

cw · Banned

These are the type that I have used for years. You have
to be kind of stout to use them with some spring guns.

TONBON · Veteran Member

Thank you Slavia.
I just needed some pics to get an idea of how to do what i need to do, slowly and under control.
i'm getting together washers to use for/with thrust washers.
i got some .5 mm hardened steel shim washers, these are tough.
i think i'll combine 3-4 with a store bought thrust washer, i should be ok.
when i took this apart, i removed the trigger end, then the spring.
i assume that this is the correct procedure for this.
i did not try to remove the seal. i gave the piston that the spring hat goes into a tug. it didn't want to go, so i left it. just greased the spring.
anything i need to watch out for if i try and remove the seal???

cw · Banned

The seal most likely has nicks in it. If it does, you'll need
a new one. Be sure to de-bur all of the holes and slots in
the compression tube or the same thing will happen to the
new seal.

Make sure all of the parts are very clean before applying
lubrication.

Slavia · Moderator

Amigo · Veteran Member

Tonbon:

Welcome to AirGunHome! I'm glad you have the good fortune to have access to machine tools - making an airgun hobby even more fun.

CW's post of 1/5/09 9:34am with photos, on close examination, speaks volumes. Notice that only two washers are shown at each end of the power spring and those washers are at least 1 mm (.039") thick (see CW's 8:09 pm post). The (2) washers are near the thickness/diameter of the spring wire.
A thin washer or multiple washers in the neighborhood of .5mm (.020") could deform under the pressure of the end of the last coil at each end of the spring rendering the flat washer bearings useless as floating bearings.
If in fine tuning spring pre-load, a washer thinner than 1mm is necessary, it should be positioned/sandwiched between the thicker washers. Note other posters recommendations that all surfaces of all washer/bearings should be coated with a film of 60% to 70% molybdenum disulfide (MoSo2) grease.
Another thing about washers, a heat treated tool steel grade 8 washer is far superior to a $0.03 dead soft 1010 -1018 washer, in this application.
Also would recommend that the end of the wire at each end coil be rounded and polished (800 to 1200 paper minimum) so the wire end can rotationally "skate" on the the first washer it directly contacts.

Now, a couple things about coiled wire compression springs that I have learned over several decades of building stamping dies, diecasting and plastic injection molds, all of which utilize compression springs, for a variety of different purposes and applications.
A fully compressed spring that is allowed unrestrained decompression will break sooner than later. Dry firing a spring powered airgun is an example.
Compressing a strong compression spring to the point of coil binding where each coil is pressed tight or stacked against its adjacent coil will reduce its life considerably. The greater the wire diameter and the harder the wire the sooner the failure when bound or nearing the point of binding/stacking.
Several times I've read that professional airgun tuners recommend calculating the bind point by multiplying the spring wire diameter by the number of all coils, then adding a minimum of 0.125" (3.18mm). They use that total as the minimum length that the "average" airgun spring can be compressed to. I suspect that wire in the .125 to .132" range should be given a safety factor minimum of about .200"(5mm) and be included in the calculation. That is what I do and I'm not plagued with spring failures.
Experience has shown me that a bound spring is soon either a dead spring or a broken spring.

I did not mean to write a book, but if a has the will and the means to do his own work, I like to pass along what works for me.

Welcome to a fun hobby Exclamation

Amigo

cw · Banned

Good info Amigo, I might add though, that I have used mild steel
washers before. I surface (case) harden them after lapping them
together.

Amigo · Veteran Member

Yes, a casehardened washer, provided it's not too thin and still has a soft core, makes the more efficient spring bearing surface in this airgun application, and others of a similar nature as well.

CW, you make a good case for keeping a can of "Kasenit" handy along with taking good photos.

Regards,

Amigo

cw · Banned

Or you could make your own "Kasenit". Finely powdered burnt
leather in a lithium soap base grease works great. It's awfully
smoky and smelly, but works great. Anything containing a lot
of carbon in a fine matrix usually will work to impregnate said
carbon into the iron/steel surface.

TONBON · Veteran Member

The thin washers i can get are haaaaard. you can't file 'em. they have to be ground down to size. you need to use a dremel on the hole.
Slavia, you mentioned i may have nicks in my seal. no prob. do you know where i can get a new one?

super6 · Member

I would recommend a good lube tune along with honing and deburring before trying to squeeze a few meaningless FPS out of your gun. You're getting the cart before the horse.

Do a search on James Maccari as a source of lubes, and aftermarket piston seals, springs, etc.

I tune every gun I get now after firing a few pellets, if any. I find problems in every new gun regardless of brand, price, and country of origin. A good tune eliminates a 1000+ shots to "break-in" the gun. A few dozen shots will seat a new piston seal. The gun will be far more comfortable to shoot, smoother overall, easier to shoot accurately, and you may gain a few FPS. My $.02.

TONBON · Veteran Member

sshh i'm playin
Thank you,
everyone for all your help.
i've found out what is possible,(or what i'll do), with this gun.
i'm happy with it. i tried the poly mags, and they shoot better than i can hold. they hit hard. i want to be prepared for next disassembly, with all my tuning parts ready. grease, tar,etc.. Cool

i'm using this to keep shooting while i'm poor. Crying or Very sad

tuning and customizing my toys is what i do. i have a mosin nagant that iv'e got about 1/3 covered in woodburn instead of checkering, Naughty

plus lots of metalwork. butterknife bolt handle, custom scope mount.
this will be another in a long line of personalized toys.
i'll be back Headshot