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PostPosted: Wed Oct 07, 2015 5:22 pm 
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Location: Hill Spring, Alberta
I'm wondering if I have some sort of record. I broke my Surge (490) mainspring a while ago because it had many thousands of pellets fired with it, then broke my new (1200 fps) mainspring the other day, probably because I damaged my new seal when I installed it, and maybe contributed to by a bit of dieseling with the first few shots.

Today I broke my Quest 1000 mainspring but I'm pretty sure I know why.

Directly above the trigger group is a small hole in the action which isn't threaded but I thought it was for a scope stop. It's in about the
right place for that.

I had trouble getting my scope mounts to stay still and since the Weaver rail I was using didn't have a scope stop screw, I cut a piece of the back end of a drill bit, dropped it behind the rail in the hole which I thought didn't go all the way through, and it solved my scope movement issue.

HOWEVER, unbeknownst to me, what I thought was the bottom of the hole must have been a coil of the main spring. I had put the cut end of the drill bit in the hole so that the top looked good, but I hadn't made the cut end smooth, so it just worked on the spring until today when the spring shattered and the gun wouldn't cock.

The good news is I'm getting better and better at tearing these things apart, de-burring them and honing the compression cylinder. I hope 600 grit for the finish is appropriate!

Peter :D


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PostPosted: Wed Oct 07, 2015 5:38 pm 
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Location: United States
Oic. Live and learn... I prefer to use the Centerpoint one-piece mount in medium height, which is in the guide I sent. It's pretty strong and if needed you can add two more clamp screws which make clamping better and look better imo. You can also replace the oem M5 stop screw with an M6 if you make the hole in the gun bigger to match. You can do that to most any mounts, maybe even drill/tap your picatinny adapter.
The seal mod we discussed will reduce your scope mount issues, especially if you stick to heavier pellets.


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PostPosted: Wed Oct 07, 2015 5:51 pm 
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Location: Hill Spring, Alberta
The hole in my gun isn't threaded, but it will be soon, and I'll install a scope mount stop.

Peter :D


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PostPosted: Wed Oct 07, 2015 10:10 pm 
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I meant the mount, see the pix "Scope ring stop pin". I don't believe you'll need a larger M6 screw, just that's it's an option.
So what picatinny adapter do you have on it? Most of those things don't grip all that great which is one reason why I don't use them. If you have a link to it and/or a pix of yours I can throw in my 2 cents on modding it or tossing it.


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PostPosted: Thu Oct 08, 2015 10:34 am 
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Location: Hill Spring, Alberta
My Picatinny rail is one I think I ordered from Amazon because it had a 5 slot overhang and 4 tightening bolts. I don't see a brand name on it, and I had to modify it to get it to fit on my dove-tail. It has a very small (M3?) set screw in a place my gun doesn't have a hole so I've tapped the existing hole and fit a shortened M6 screw into it making sure the end was smooth and flush with the inside of the chamber.

Peter :D


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PostPosted: Thu Oct 08, 2015 3:29 pm 
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At least it has four screws, most are for firearm use or non-springer airgun use so they only have two. As long as the metal you tapped is thick enough to support the screw you should be fine. Like I have an adaptor that came with an Umarex Octane and it's built like a skeleton so no way it could support a setscrew. It works on the octane because the dove rail has four slots that the four clamp screws fit into so I doubt it's going anywhere, but you can't move the mount from that position or put it on another gun unless you cut grooves in it too. Actually I wish all picatinny airgun mounts were like this one because it's super light, super low and removable if you want dove. Guns like a Trail have a heavy solid pic mount that is brazed on (I think) so no guarantee it'll stay attached. Lots of NP2 owners found that out the hard way. Plus when it breaks your scope falls on the deck, so if you bought a nice scope you may be kissing that goodbye too.
Regular dovetail mounts usually have lots of meat to accept a setscrew, except those hollow see-thru types but they can work with a long setscrew if needed. If the gun is tuned, to me that means leak free and the seal mod, and at least mid weight pellets are used then you may not need a setscrew at all. I've converted some from the oem M5 setscrew to M6, but not for strength, I do it so it's less likely to tear up the gun. The thinner pin on an M5 can dent the hole easier, or cut a groove easier in softer metal. Like a Diana with a bolt-on dovetail is softer metal and the M5 screw can plow right thru it. An M6 has more surface area so less likely to do so. An unmodified gun with harsh reverse recoil can bend or break an M5 so they can bennie by the strength of an M6.
Some setscrews are not ground to a shaft like in that pix, instead the end is ground to a point. A classic example of the mfg trying to save a penny. Those have much less surface area so much more prone to cause damage, even cutting a groove in the receiver. So if you ever run across one I'd replace it with one like in the pix.
The overhang you mentioned I assume is five unsupported pic segments sticking out? I haven't heard of any breaking but again most of these things are made for firearms and may not be designed to handle a springer. Or like many things it may be a balance of just strong enough so returns cost less than making them stronger. So I'd keep an eye on it just in case.
Another thing that's an issue with aluminum adapters/mounts is the female threads in the mount for the clamp screws can give out. Most of these things are made in China or similar so the threads on the screws will be rough which will tear up the alum making it weaker You can use a wire wheel to smooth the bolts threads to minimize this. You should also lube the threads with grease. I'd say find some better quality bolts but easier said than done. You can also use longer bolts for more surface area, like most are ~16mm but most will accept 20mm. This spreads the force over ~50% more area, plus more area means you can tighten the screw more. Many people strip theirs because they're trying to stop the mount from sliding but at some point the threads give out .That extra length can make all the difference. You can also drill/tap to the next size. Most are M4 so you can go to M5. Going from an M4x16 to M5x20 is huge. Probably tmi but some options to keep in mind


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PostPosted: Fri Oct 09, 2015 8:54 am 
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Location: Hill Spring, Alberta
Well I've done what I can with the trigger but since the gun is completely apart I'm giving it a complete tune, paying particular attention to smoothing the insides of the cocking slots, new seals etc. Hopefully that will end my spring breakage issues (I'm doing the same with my Surge).

I'm looking forward to trying it when the tune is completed (I've ordered some of that dry lube stuff you recommend in your tuning guide) because it has been a "harsh" shooter from the beginning.

I looked it up on Stephen Archer's Rate a Gun site and it comes in as being hard to tame. I actually like it a lot but a little smoother will be nice.

Today I'll put the first button on the pistons from both guns.

I'm really glad to have other guns to shoot while these two are down.


Peter :D


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PostPosted: Fri Oct 09, 2015 5:45 pm 
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Location: Hill Spring, Alberta
I got the buttons in today for both the Surge and the Quest.

I discovered that 2 part epoxy wouldn't stick to the Quest piston, so I used "super glue". The epoxy stuck just fine to the Surge piston.

Anyway I got all the buttons on and discovered that both rifles had a narrow spot in the chamber about 1/2 way down the cocking slot.
The one on the Surge wasn't too bad but the Crosman one was bad enough I had to get the hone out with 400 grit and then 600 grit to enlarge it. Both rifles still have a slightly constricted spot but I'm hoping it won't be an issue.

Now I'm waiting for the dry lubricant, a seal for the Surge and the springs.

Boy, this hobby is so much better than bird watching and butterfly collecting! (I never did those things, but I'm pretty sure this is better.)

Peter :D


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PostPosted: Sat Oct 10, 2015 3:55 am 
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Location: United States
That tight spot is pretty common. I think it's mentioned in the guide. I use more course paper to hog out tight spots, even up to 150 grit. The buttons have to get past it so the more it's opened up the thicker the buttons can be so I make the effort to open it.
Epoxy has worked for me but I guess it would depend on what epoxy you used. Plus the metal would need to be sanded and stripped of oil etc. Still weird it stuck to the one and not the other... Super glue works pretty good so that's what I usually use.
The Quest can be made to be very smooth. I'd be sure to sand the seal and sleeve the piston, those probably make the biggest differences. Using spring tar can quiet it even further if you want to deal with it. You can also fill the guide with silicone sealant or foam rubber to help dampen noise. Plus that silicone plug in the spring. An oem spring should fit the guide fairly well but other brands may be too loose.


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PostPosted: Sat Oct 10, 2015 10:33 am 
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I've honed the cylinders out so that the tight spots are barely noticeable.

I sanded the Crosman seal this AM and using heat put it back on. For some reason it fit really loose on the piston dove-tail. I've ordered a couple of new ones. (I sanded the correct (face) side.)

This probably a dumb question but may I assume the "guide" that I should fill with silicone is the one on the rear. I couldn't find the reference in your tuning guide.

From your description, the silicone plug just fits snugly inside the spring where it can move back and forth.

I really appreciate your patience and help. I think we're even still on topic with replacing a broken spring.

Thanks

Peter :D


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PostPosted: Sat Oct 10, 2015 8:03 pm 
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The seal should be tight, more or less. Do you mean it spins easily, which might be because it's lubed, or it actually has play and can flop around? Sanding the back side will cause it to be loose of course, but the face shouldn't. I also can't stress enough that you need enough seal sticking out past the dove to prevent the dove from hitting the breech, which I'm sure you did but I gotta say it.
The tuning guide is not complete so lots of little details like packing the guide with silicone or foam is still not in there. Yes the hollow rear guide is what you fill, the front guide aka "top hat" is solid. The silicone plug in the spring is free to move around, and when cocked it should be partially squeezed between the top hat and guide. When fired it ends up ~mid way in the spring and helps dampen vibration and noise. It's not required, just one more little thing to help.
And know that when filling the guide with silicone it may take a while to dry, and the stuff in the center may take a very long time since it'll be sealed at each end. If you want to shoot it asap then I suggest using foam, maybe black foam weather stripping stuffed into it or whatever. Just know that shooting can shake just about anything loose so if using foam be sure it's in there tight. If silicone it may help to let it bake in the sun for a few days, and/or maybe fill half or less at a time. I think just filling just the fwd end half or third will give you most of the benneis. If you use a silicone plug for the spring you should have the end of the guide filled with something so the plug cannot enter the guide, so filling the first third of the guide while making the plug is ideal, then a couple days for them to dry should be good.
You could also make a new guide if you wanted. Ideally a solid piece of tough plastic that is slightly larger in OD to fit the spring better, and long enough that it almost kisses the top hat. Or maybe a metal tube, maybe 1/2" .060 wall that's sanded down to fit. Either one would be a lot of work imo but some people have the tools, materials and drive to do it.
If you want to make the oem guide fit the spring better you can make the guide squarish. Like squeezing it in a vice. Not ideal but not bad, but it's really more of an easy fix for an aftermarket spring like a Vortek that's too big. You could sleeve the guide instead but I don't think it'll be easy finding the material to do it. I suppose you could button it, like 3-4 strips of plastic glued to it and sanded to a perfect fit. Just some ideas if you or anyone is interested.
The sheath in the piston is the biggest contributor to spring noise reduction imo. Even one that's still loose makes a big difference. A more snug fit is better but harder to do. Finding the correct thickness of plastic might be difficult so an option is to double up thinner sheaths. The ID of the piston varies but is ~.060-.070" bigger than the OD of the oem full power spring. So one layer of 2-liter soda bottle should reduce the piston ID by .025-.030", two layers might be perfect or a bit snug. I've made quite a few sheaths plus I'm good at that sorta stuff so making them is no biggie to me, but lots of people get frustrated and give up, or make it loose fitting which I can't say how that will hold up over time. By loose I mean not pressed against the piston so it moves around and imo will likely break free.
Then there's always converting to a nitro spring which should be in the guide? Crosman sells two springs that would work well, one is the standard spring most commonly used on full power guns like the Titan. They make full power but being so strong they also have drawbacks like additional scope and mount stress and upsetting accuracy a bit. The other spring is lighter so it's easier to cock, smoother shooting, less scope stress, quieter etc. I believe the lighter spring is much less likely to leak which is a big bonus imo. Not because the pressure, which is actually the same, but because the shaft is smoother. Of course you lose some power with the lighter spring but it isn't bad and you may prefer it for all the bennies. The lighter nitro in a 177 gun with ~8gr pellets makes a very nice shooter in the 800fps range.


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PostPosted: Sun Oct 11, 2015 7:54 am 
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Location: Thunder Bay
Just thought I'd chime in here...
I just detuned a Crosman Fury springer to around 13 ftlbs with a stock spring. I did this by reducing the preload by shortening the length of the large solid steel spacer at the back of the spring guide. At first I tried just removing it. The preload was almost non-existent, and velocities were all over the place. Probably too much uncontrolled piston bounce. After a few tries, I settled on removing about half of the spacer, thereby reducing the preload by about 50%. The gun shoots around 870 fps with 7.5 gr pellets now. Folks on different airgun sites seem to agree that reducing the preload will decrease stress on the spring and increase its lifespan.
The detune brought out all the benefits already mentioned, like less cocking force, less recoil, less noise, etc. The one benefit that surprised me is the ability to shoot different pellet weights, styles, and manufacturers to the same poi. I detuned a Ruger blackhawk elite with a Vortek docile spring to about 12 ftlbs. Same thing happened, but not as pronounced as the Crosman. The Fury will shoot different pellets into a dime at 15 meters. Of course, groups open up pretty fast as distances increase.
I have a Fury Nitro Piston (full power 17+ftlbs). Tempermental racehorse that's giving me fits. One day it's shooting ridiculously small groups, next day it's shotgunning. Of course it has nothing to do with my shooting ability. I think the NP gets jealous of the time I spend with its older sister, the Fury springer. They sure have different "personalities".
Truth be known, the detuned springers are just plain easier to shoot. Not very hold sensitive, and not pellet picky. I sure don't miss the 100 or so fps I lost in the detune.

I learned lots in this thread. Thanks folks!

_________________
12 springers and a couple of pumpers.
2 lathes and lots of scrap metal.

I'm not multitasking. I'm doing something else until I remember what I was doing.


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PostPosted: Sun Oct 11, 2015 8:10 am 
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Location: Hill Spring, Alberta
Yes, the seal was completely loose so it'll be replaced.

I like the idea about "button guides" on the rear spring guide. I have two silicone plugs drying (one for each gun I have torn down). I'm wondering if a person stuffed the rear guides with insulating foam rubber then put a silicone "cap" on if that would work.

Yesterday I read the section in the tuning guide about spring washers. I have modified one to fit the top hat and I'll get something today when I go into town (we live about 30 miles out) to fit on the spring guide.

I also got looking at the two on the Umarex.

The rear spring guide washer is metal sitting on the "plastic" base of the spring guide and its face is chewed up.

The front doesn't have a top hat, but a thin metal sleeve folded in on the front end much like the ones you recommend to be made from soda bottles. The end of that sleeve is also chewed up.

I'll try to get appropriate washers to put in place and I'm wondering if the spring binding on the chewed up washers caused stress and contributed to the spring breaking. That Umarex has many many thousands of pellets fired through it, mostly with the oem (490 fps) spring.


Peter :D


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PostPosted: Sun Oct 11, 2015 3:40 pm 
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That's weird about the seal. So it fit fine before, then you sanded the face and it somehow became loose... I don't even have a theory for that one, unless you put the Crosman seal on the Surge piston, but that would obvious.
The Surge won't have a top hat like the Crosman, nor does it need one, especially with a plastic liner added. Of course you don't want to fill the guide tube in the Surge, only the Crosman, but yes you could fill the end with silicone, then after it cures stuff the remainder with foam.
The metal piston liner in the Surge can be replaced with plastic, either thicker or two thinner ones to make it thicker, but I usually add a plastic liner inside the metal one. As long as the metal liner is more or less straight, round and dent free it'll be fine.
The attached pix is a Diana liner and you can see where I sanded high spots to make it a better fit in the piston because it was not a very good fit as it came. I also sanded the inside so the liner and inside the piston. The front end of the liner is finished and ready but the aft still needs to be trimmed. Or you could go a step further and make that excess fit the piston skirt by filling the space between it and the skirt with more plastic. It's a pita but the longer the sheath the better it works. If that doesn't make sense it will when you insert it into the piston. You could also just let the excess hang out unsupported, but not so far that it extends past the piston.
Of course when you size the plastic liner it needs to be after all sanding to the steel liner is done and it's installed in the piston. You also want the plastic seam to be opposite the metal seam.
A Diana will have a washer over that chewed up part but I guess on yours they cut it out to save a penny. I'm guessing the washer on the guide was very thin and basically ruined? So you have two washers to make. This will shim the spring up so hopefully it won't coil bind, if it does then you need to trim the spring a bit.
No I don't believe the spring binds at either end or it would cause an issue. I do work like this to prevent damage and metal slivers getting around. Making bearings out of washers is popular but I've never noticed any "spring torque" that people complain about, or a difference after adding bearings. I think it's psychological but many are really insistent and want bearings. If you make bearings, which certainly won't hurt, it'll take up more space and much more likely to cause coil bind.


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PostPosted: Mon Oct 12, 2015 7:53 am 
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My only guess about how the Crosman seal became loose is that I heated it too much, and then installed it hot. It stretched but didn't completely shrink back to the original size. The next installation will be with boiling water instead.

I put a plastic liner in my Surge liner but it made the spring bind. My spring is bent (new one hasn't arrived yet) so it exacerbates the problem but there just doesn't seem to be enough room. I made a liner for the piston without the metal liner and it seems to be about right.

The rear of the piston has a very slight flare which was nice for getting the plastic liner started in, but means that the last little bit of the liner isn't pressured like the rest and the edges overlap. The rest of the liner fits very tightly into the piston so that the plastic in the slot feels very hard. When my new spring arrives I'll check for fit and decide if there's room for an additional liner. Then I'll dry lube as appropriate and super glue the edges to be on the safe side.

Today I'll make a liner for the 1000.

Silicone plugs for both guns are very slowly setting up.

Some time ago, I broke, repaired, and partly re-finished my 1000 stock, so while the gun's apart I've stripped it right down and started (two coats so far) to refinish it. The wood grain is actually quite nice.

Looking forward to getting it all back together and shooting.

Peter :D


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