GTA
Support Equipment For PCP/HPA/CO2 and springers ,rams => Tuners => Topic started by: truck driver on September 15, 2019, 01:03:50 PM
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What is the best material to use to make a piston spring sleeve?
I have tried a poly sleeve made from a gallon water jug but still not sure if it improved anything and only slightly reduced the spring noise.
The material was .002" thick and was cut to fit perfectly inside the piston with no over lap.
Any suggestions will be appreciated.
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Some have used teflon they bought from amazon.
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The materials I have used to create piston sleeves depends on the thickness required. Materials from gallon water jugs, bleach bottles and 2 liter soda bottles have all been used at one time or another. I prefer the white plastic of bleach bottles; seems to holds up very well.
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Im not sure what other leading tinkerers think, but i proved fairly conclusively (to myself) tuning a whole raft load of club members guns, that if the gun is fitted with a correctly machined guide and top hat, that a sleeve is not needed...
Sleeves can also introduce unreliability issues as folded over ends fracture or the spring is gripped slightly at full compression when the spring is at its biggest diameter...
I have pulled out PTFE sleeves that have been torn up, or worn almost through on one side...and bent bits of sharp on metal can sleeves..
A very nice guide will stop a spring slapping against the sides of the piston, as will a nice top hat...
Its clean, reliable and solid....and stood the test of time in many tunes ive done...
The only caveat to this that i came across, is that of the HW80 in the Uk supplied version, where the Uk spring is just too small inside the piston for the guide/top hat to completely kill all the twang...and probably needing of some sort of sleeve ..
Just my view ...not intended to be negative..
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Im not sure what other leading tinkerers think, but i proved fairly conclusively (to myself) tuning a whole raft load of club members guns, that if the gun is fitted with a correctly machined guide and top hat, that a sleeve is not needed...
Sleeves can also introduce unreliability issues as folded over ends fracture or the spring is gripped slightly at full compression when the spring is at its biggest diameter...
I have pulled out PTFE sleeves that have been torn up, or worn almost through on one side...and bent bits of sharp on metal can sleeves..
A very nice guide will stop a spring slapping against the sides of the piston, as will a nice top hat...
Its clean, reliable and solid....and stood the test of time in many tunes ive done...
The only caveat to this that i came across, is that of the HW80 in the Uk supplied version, where the Uk spring is just too small inside the piston for the guide/top hat to completely kill all the twang...and probably needing of some sort of sleeve ..
Just my view ...not intended to be negative..
All views are appreciated so no negative read.
Some of us don't have the machinery to turn out Top hats and guides so we resort to piston sleeves.
I can see problems where the Tinker/home tuner would run into problems when spring ends aren't polished and lubed since the spring turns when it uncoils. I can see where a thin steel spacer/washer could be used between the sleeve petals and the spring to alleviate any problems if there is room for one.
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I have used the quart milk containers in the US as piston sleeves, they are much thicker than milk containers in the UK.
Aerosol cans are about 9 thou, I use those if needed.
I like to sleeve a piston as it stops any grease coming out of the cocking slot and into the cylinder.
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Im not sure what other leading tinkerers think, but i proved fairly conclusively (to myself) tuning a whole raft load of club members guns, that if the gun is fitted with a correctly machined guide and top hat, that a sleeve is not needed...
Sleeves can also introduce unreliability issues as folded over ends fracture or the spring is gripped slightly at full compression when the spring is at its biggest diameter...
I have pulled out PTFE sleeves that have been torn up, or worn almost through on one side...and bent bits of sharp on metal can sleeves..
A very nice guide will stop a spring slapping against the sides of the piston, as will a nice top hat...
Its clean, reliable and solid....and stood the test of time in many tunes ive done...
The only caveat to this that i came across, is that of the HW80 in the Uk supplied version, where the Uk spring is just too small inside the piston for the guide/top hat to completely kill all the twang...and probably needing of some sort of sleeve ..
Just my view ...not intended to be negative..
I agree completely! With the old design HW cocking shoes the piston sleeve was NEEDED to support the cocking shoe over the spring coils...........
(https://i.imgur.com/u9yH4c4l.jpg)
The newer design HW cocking shoes are supported on the sides of the cocking shoe slot so a liner isn't needed..........
(https://i.imgur.com/2gbPqo0l.jpg)
My HW95 came from the factory with a piston liner looking like this at the teardown when stripping and relubing with Krytos.......
(https://i.imgur.com/GC4Lj5sl.jpg)
After stripping/relubing the gun was shot with both with/without the piston liner. I found that using a tight fitting guide and top hat there was no difference in the shot cycle.
Perhaps if the gun was loaded with diesel prone dinosaur grease slathered on the spring a liner would keep some of the excess lube from being thrown against the receiver ID, however the liner only covers a portion of the spring after the piston surges forward so it's a moot point. A few years ago I bought a Vortex PG2 kit with it's "inner guide and outer liner" and it did a good job killing twang & vibration, however the shot cycle wasn't any quieter than that of a properly fitted spring guide and top hat, even without a piston liner.
Anywhoo.....my HW95 still has the piston liner installed simply because it doesn't matter and it was "free" with the gun. As a side note, I have a couple old HW95 piston liners (from the R9 when the cocking shoe was supported by the liner" and it appears to be made of "spring steel" (does spring after being squeezed) and the material measures .3mm (.3mm= 0.0118in).
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I use 2 liter soda bottles and overlap as required. I usually start with it too tight and extra long so I can grab it above the piston skirt. I check the spring fit and if excessively tight, pull the sleeve, trim some off the edge, check the fit again and repeat until it feels right. I then mark and trim the extra length off the top. I usually put heavy tar on the outside to help it stick in the piston.
It should be a medium push fit. If too easy, it won't dampen, and if too tight it can bind.
Hope that helps!
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Im not sure what other leading tinkerers think, but i proved fairly conclusively (to myself) tuning a whole raft load of club members guns, that if the gun is fitted with a correctly machined guide and top hat, that a sleeve is not needed...
Sleeves can also introduce unreliability issues as folded over ends fracture or the spring is gripped slightly at full compression when the spring is at its biggest diameter...
I have pulled out PTFE sleeves that have been torn up, or worn almost through on one side...and bent bits of sharp on metal can sleeves..
A very nice guide will stop a spring slapping against the sides of the piston, as will a nice top hat...
Its clean, reliable and solid....and stood the test of time in many tunes ive done...
The only caveat to this that i came across, is that of the HW80 in the Uk supplied version, where the Uk spring is just too small inside the piston for the guide/top hat to completely kill all the twang...and probably needing of some sort of sleeve ..
Just my view ...not intended to be negative..
I agree completely! With the old design HW cocking shoes the piston sleeve was NEEDED to support the cocking shoe over the spring coils...........
(https://i.imgur.com/u9yH4c4l.jpg)
The newer design HW cocking shoes are supported on the sides of the cocking shoe slot so a liner isn't needed..........
(https://i.imgur.com/2gbPqo0l.jpg)
My HW95 came from the factory with a piston liner looking like this at the teardown when stripping and relubing with Krytos.......
(https://i.imgur.com/GC4Lj5sl.jpg)
After stripping/relubing the gun was shot with both with/without the piston liner. I found that using a tight fitting guide and top hat there was no difference in the shot cycle.
Perhaps if the gun was loaded with diesel prone dinosaur grease slathered on the spring a liner would keep some of the excess lube from being thrown against the receiver ID, however the liner only covers a portion of the spring after the piston surges forward so it's a moot point. A few years ago I bought a Vortex PG2 kit with it's "inner guide and outer liner" and it did a good job killing twang & vibration, however the shot cycle wasn't any quieter than that of a properly fitted spring guide and top hat, even without a piston liner.
Anywhoo.....my HW95 still has the piston liner installed simply because it doesn't matter and it was "free" with the gun. As a side note, I have a couple old HW95 piston liners (from the R9 when the cocking shoe was supported by the liner" and it appears to be made of "spring steel" (does spring after being squeezed) and the material measures .3mm (.3mm= 0.0118in).
Completely agreeing with you buddy regarding the dinosaur grease...This is an important point..
If you use Delrin Guides, you really do not need the Dino grease to damp the spring in the first place.
I pretty much run mine dry, maybe a meniscus of moly wiped on and back off the spring....Thus, no grease to reduce velocity, cause temperature sensitivity issues and no need for the liner to contain the absent grease...
Ok, i take the point regarding not having the facility to machine up your own guides etc and sleeves offering at least some chance of keep your tunes completely DIY ...i respect that...
They are not hard to get hold of these kits though fellas....Vmach do good ones..Tony Leach higher end kits etc..
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Heat shrink tube glued and shrunk (in an oven) onto the spring guide often or normally works better to eliminate twang and vibration than a piston liner.....or do both.
This is called a "shrink tune"; if properly done it will last for many years.
By the way, some incorrectly call heat shrink tubing "shrink wrap." Shrink wrap is entirely different.
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Well Guys I ordered some ultimox 226 and a sheet of .03" thick teflon sheeting and everything arrived so I broke the D48 down and cleaned all the grease out and deburred what needed smoothed up plus polished the spring ends. While I was at it I picked up a couple of stainless steel fender washers about the same OD as the spring and thickness the same as the steel shield between the spring and guide. Thinking this keeps the spring from eating up the guide I thought I would try and make one for inside the sleeve so the spring wouldn't eat on the petals and turn freely when it unwinds. The sleeve was made so the spring would slide easily in and out of the piston so there was room for expansion when the spring compresses and not bind up.
Put a mirror polish on the new spacer and a dab of super lube on each end of the spring and a very light coating on the spring also put a dab behind the piston seal and on the back of the piston.
The rifle was reassembled and test fired for function.
The rifle cocked as before with no binding and the piston latched on the sear. The spring didn't bunch up in the sleeve and the spacer didn't cause any problems with not latching.
I added a lot of material inside the piston and was wondering if I would be tearing it back down and changing things.
So far it works and the twang is gone and a solid thwack when fired.
I'll have to chrony it and see what affect the changes made.
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Well Truck Driver...if one takes the time and trouble with a sleeve that you have, you stand a good chance of this being ok.
The 0.3mm Teflon is a better choice than the 0.5 mm because we need to remember that 0.5mm equates to 1mm of clearance...as the 0.5mm sits on both sides of the spring which equals 1mm...A simple but surprisingly common mistake many make....most springs only have about 1mm clearance which will bind on 0.5mm.
The Teflon does chew up but takes a few 1000 rounds...so it makes sense to make a few sleeves up then just swap them out each time you do a service..
I would be wary of using tin cans. There are all sorts of problems here.
Many propriety beer cans that may seem ok (after you have checked them with a magnet to ensure they are not aluminium) are actually Tin and has a poor coeeficient of friction against steel..
Also your thruster washers will pick up and gall on the folded petals as Tin is soft..
It might be better to use True Shim steel if going this way...Its True steel and relatively hard...
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Well Truck Driver...if one takes the time and trouble with a sleeve that you have, you stand a good chance of this being OK.
The 0.3mm Teflon is a better choice than the 0.5 mm because we need to remember that 0.5mm equates to 1mm of clearance...as the 0.5mm sits on both sides of the spring which equals 1mm...A simple but surprisingly common mistake many make....most springs only have about 1mm clearance which will bind on 0.5mm.
The Teflon does chew up but takes a few 1000 rounds...so it makes sense to make a few sleeves up then just swap them out each time you do a service..
I would be wary of using tin cans. There are all sorts of problems here.
Many propriety beer cans that may seem OK (after you have checked them with a magnet to ensure they are not aluminium) are actually Tin and has a poor coefficient of friction against steel..
Also your thrust-er washers will pick up and gall on the folded petals as Tin is soft..
It might be better to use True Shim steel if going this way...Its True steel and relatively hard...
clarky;
Thanks for the info but for shim stock I use what is available and in this case a stainless steel fender washer polished and fitted. The stainless won't gull when the hardened spring turns on it and the Ultimox 226 will also help with that and excessive wear.
So far the D48 tested out perfectly and is making 24fpe with 14.3gr CP dooms for 870.2 fps.
Wish you guys on the Island could enjoy the more powerful rifles that we can here on the Continent in the Colonies. ;) ;D
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Theres no need bud....
There is a new thinking in town...Everyone here got tired of running 12 ftlbs margin but found 10.8ftlbs so much nicer to shoot and so much easier to shoot accurately...
We have super tuned 98s, 97s and Tx200 s doing sub inch groups right out to 55 metres in some cases...
But you can still use a PCP on FAC if your landowner with an FAC..