Tuning Sizing piston seal

[survivor45]

I have a new Vortek HW style. 26mm piston seal.
The outside diameter of the seal 1.035”
And the inside diameter of my cylinder is 1.006” (to the best of my ability to measure)
My question is what dimension do I turn down the seal to , to fit this cylinder?
Thanks.

 

[Hateful McNasty]

I feel its more to fit then a size. I guess you want the seal on the piston just tight enugh to when vertical it dont fall freely but takes a slight amount of pressure to push it down .. now thats a judgement call / experance feel on what feels right.

I tend to add a few extra seals to experment with in case , or when i test one if not happy i can take more off it or try another seal and see if i can better . ( You can take off but you cant put it back on )

Im sure guys that do this off there own expreance on what they find best in there stuf. Then i thought the vortex was a more drop in seal? ... Yet to try one .

If your not sure, it's best to start tight and test it and take a bit off at a time and check your work as you go.

Im no pro but i like the job and each trip in just adds to the experience..

Matter of fact i made a new spindle from a hex bolt to mimic the piston button to turn in my drill . Not fancy but works

 

[jarmstrong]

I size mine to gently free fall from the tube by gravity but stay put in the cylinder when I put my finger on the transfer port. That is how I was learned

I adjust my barrel hinge, with the gun cocked, vertical pointing up,, with the barrel at 90 degrees. the barrel stays at 90 degrees but a light or slight touch causes them to fall

 

[Hateful McNasty]

I size mine to gently free fall from the tube by gravity but stay put in the cylinder when I put my finger on the transfer port. That is how I was learned

I adjust my barrel hinge, with the gun cocked, vertical pointing up,, with the barrel at 90 degrees. the barrel stays at 90 degrees but a light or slight touch causes them to fall

There's a fine line between too tight and too loose.
Too tight boggs the fps , too loose you may get higher fps but could cause slamming. Thats somthing to go back in and check the seal gace for any bad /deep transfer port marks or cracking around the button area .. this is that your own personal judgement call thing .

Also the seal will ware in some over time and loosen up a tad more..

Personly i think your doing right by doing ot yourself . Then hay... If you goof the first you then know a little better the next one. Your own work gives it the accomplishment feeling. We all had our first ones to..

By the way what spring did you go with?

 

[Sqwirl57]

Yeah I dont even bother sizing the Vortek seals I just let the gun do its thing. Velocity just slowly climbs for the first tin or two but accuracy isn't really affected too much.

If one was clearly way oversized that would be a different story but I've been fortunate enough not to run into that so far. @Hateful McNasty has a pretty solid system to take care of that. I have done something similar with ARH seals in the past. Those NEED resizing by design.

 

[jarmstrong]

ARH springs and seals in 2 HW50s,, sold the 22 cal HW 50, still have the 20 cal
I have 3 Vortex seals awaiting on the shelf for the next tear down

 

[Hateful McNasty]

Yeah I dont even bother sizing the Vortek seals I just let the gun do its thing. Velocity just slowly climbs for the first tin or two but accuracy isn't really affected too much.

If one was clearly way oversized that would be a different story but I've been fortunate enough not to run into that so far. @Hateful McNasty has a pretty solid system to take care of that. I have done something similar with ARH seals in the past. Those NEED resizing by design.

Of the arh seals each one gave me a different result from not happy to now i like this fit, sweet. One would never get over 825 fps or have that first shot bad or nice transfer port mark..lol. Then did not think i did one any different then the other. I was glad i threw a few seals in the order. It payed off. Also i do think your last sanding should be a more polish scratching like fine 600 grit. Lower / more course to take off is fine for that ..

Good thing with a hw break barrel is easy to dissemble and reassemble. Any rework is a breeze ..

(Disclaimer.
This is all matter of my opinion ... Results may differ)

 

[Sqwirl57]

Of the arh seals each one gave me a different result from not happy to now i like this fit, sweet. One would never get over 825 fps or have that first shot bad or nice transfer port mark..lol. Then did not think i did one any different then the other. I was glad i threw a few seals in the order. It payed off. Also i do think your last sanding should be a more polish scratching like fine 600 grit. Lower / more course to take off is fine for that ..

Good thing with a hw break barrel is easy to dissemble and reassemble. Any rework is a breeze ..

(Disclaimer.
This is all matter of my opinion ... Results may differ)

Yessir. ARH seals will rob you blind of power if they aren't sized prior to installing. My 55 went from 6fpe to just over 10fpe in a matter of turning like 1/100 of an inch off. It works wonderfully now though. I even got to trim 2x coils of the spring because I wasn't looking for much more than 6fpe in that gun.

 

[Motorhead]

Indeed ... ARH expressly states that there seals are oversize requiring sizing and fitting by a qualified airsmith ( Or something to that verbiage )

 

[survivor45]

This will be my second rebuild/tune. The last one on a Diana Mdl 45 the seal slide right on in.
Just an FYI. This seal is not going into an HW air gun.

 

[Sqwirl57]

You'd be suprised what seals fit random guns. I have HW seals in Walthers and a TX200 seal in a BSA Meteor Super. I always keep a few different ones on hand because you just never know when you'll need one

 

[Hateful McNasty]

Indeed ... ARH expressly states that there seals are oversize requiring sizing and fitting by a qualified airsmith ( Or something to that verbiage )

He offers like 4 hw seals in size .. lol

Si i got a little of everything to play with saddly he throws them all loose in a bag for you to weed them out on what one is what.. i was like come on man... Put each size seal in there own bag..lol.

But it seemed the most oversized seal. i had to do some grinding on to fit ended up being the best overall.. you could barely pry it in the tube covered in owl snot unfinished.. i jokingly said to myself " by the time i gring it down to fit there won't be any lip left to seal ". Bit it did nicely.. im shooting it now.. so far im liking it .. may best not look that gift horse in the mouth..lol

Welp trump speech on, got to go..

 

[Pellet-Head]

ARH springs and seals in 2 HW50s,, sold the 22 cal HW 50, still have the 20 cal
I have 3 Vortex seals awaiting on the shelf for the next tear down

Hi,
Is the .20 cal for sale as well?

 

[jarmstrong]

Nope, no way, that's my baby,

 

[Deerstalker]

I installed a Vortek 26 mm seal in my 2018 year HW95L .22 without any mod or sizing. 17 FPE and accurate after about 7K shots. Cocking cycle is soundless until the piston latches. Shot cycle is a sharp dull thud if that makes any sense. I used the ARH kit for the tune after a through clean/polish with Krytox GPL-205 lube.

 

[Pellet-Head]

Nope, no way, that's my baby,