Tolerance ?

samuelkeesee12 · 09-29-2010, 04:51 PM

Is there a sticky somewhere about o-ring tolerances? I have looked through all the stickies and can't find it. I know I saw one somewhere before but I can't seem to find it now. Also does anyone have any pointers for selecting o-rings?

KansasCityRellik · 09-29-2010, 04:57 PM

Don't use Buna o-rings on dynamic seals. They work good for static seals but definitely go with Urethane or Polyurethane on the dynamic ones. I.E. Bolt Sail

Ant_Diggity · 09-29-2010, 05:18 PM

I just ordered some o-rings from o-ring monkey. they are decently priced and work perfectly. there's also a few different options to which o-ring you can buy if you don't need o-rings for the entire gun. http://oringmonkey.com/

samuelkeesee12 · 09-29-2010, 05:31 PM

Yes but I'm talking about o-ring tolerances, or how "tight" o-rings fit. I have heard buna o-rings are fine for any seal.

SpeedsCustom-PB · 09-29-2010, 06:13 PM

While true, a part that is moving should use a stronger o-ring; Urethane or Polyurethane. It will hold up better since their will be friction.

-Speed

KansasCityRellik · 09-29-2010, 06:34 PM

Buna do seal great and they are cheap. However; I had horrible consistency problems on my Shocker NXT shortly after rebuilding it entirely with Buna o-rings. The tolerances of the Buna on the inner firing chamber seemed to be off slightly. (Bolt seemed to be loose and did not shoot as 'crisp'). I changed all of them to the green (Therban) o-rings, as well as changing the bolt guide and bolt sail o-rings to urethane or polyurethane. All my problems went away.

Just to confirm the problem, I changed a couple of them back to Buna one at a time. For some reason the Buna just wouldn't work right anywhere the was a dynamic seal. Horrible bolt stick and inconsistencies, especially when the bolt sail was a Buna. When it wasn't sticking, the chrono was dropping off 80-100fps every 2 or 3 shots.

Gisgo09 · 09-30-2010, 02:33 AM

The section you want is in the first page of the spring mod page (not the one in the stickies).

timmyfreek · 09-30-2010, 02:41 PM

dose anyone know were to get urethane or polyurethane orings? oring monkey only has buna

KansasCityRellik · 09-30-2010, 03:03 PM

I've used www.mcmaster.com before. Prices are pretty fair and they don't charge extra for small orders.

timmyfreek · 09-30-2010, 03:28 PM

cool thanks. i never thought to check them for orings, my dad buys stuf from there all the time. lol

samuelkeesee12 · 09-30-2010, 06:02 PM

Another question related to o-rings. On zdspb.com it says the outer can o-rings are 22, but on ndz website their o-ring kits have 23. I even emailed them to see which it was and they said 23. I tried to go to smart parts website, but it was down. Which size go on the outer can o-rings?

Ant_Diggity · 09-30-2010, 06:36 PM

I use 22 and they fit perfect, 23 might be too big

The mielke way · 09-30-2010, 06:40 PM

22 is the correct size. I have about a hundred or so of them so I know they are correct.

KansasCityRellik · 09-30-2010, 06:46 PM

I have a stock HE can and it uses 22s. No idea if an NDZ can is any different.

"22's son!, 22's!"

The mielke way · 09-30-2010, 06:46 PM

www.oringsusa.com is the best place I have found to get them. I get the green HNBR-70 orings in bulk for cheap.

The mielke way · 09-30-2010, 06:48 PM

I have the NDZ can and it is 22-70.

KansasCityRellik · 09-30-2010, 06:50 PM

8c a pop for those 17/70s. Damn, that is cheap. Score.

The mielke way · 09-30-2010, 07:02 PM

I bought 100 of the 17-70 and 15-70 for like $15.00 and replace them every time I play since they are the only dynamic orings. cant get much cheaper. And with the HNBR I never have leaks. Just make sure they have enough in the inventory column to the right.

ccluff2 · 09-30-2010, 08:09 PM

Quote:

Originally Posted by The mielke way

I bought 100 of the 17-70 and 15-70 for like $15.00 and replace them every time I play since they are the only dynamic orings. cant get much cheaper. And with the HNBR I never have leaks. Just make sure they have enough in the inventory column to the right.

12/70 on the bolt guide and 16/70 on the bolt sail are dynamic as well. That is a great find and I will be buying those therban orings here soon.

samuelkeesee12 · 09-30-2010, 08:13 PM

Yeah. The paintball o-rings are rediculous. Whats the difference with the HNBR o-rings compaired to the polyurethane?

KansasCityRellik · 09-30-2010, 08:16 PM

" HNBR, aka. Therban: This material is chemically similar to Buna, except the materials are hydrogenized (addition of hydrogen). The resulting material tends to hold up longer than urethane or buna, while maintaining the same durometer as the lower-quality Buna rings. Although significantly more expensive, ideally this is the most long-lasting o-ring type available due to the long tolerances. "

**Quoted from ZDSPB.com**