There's different ways to measure o-rings. Some places use the OD, others the ID. Take the OEM and place it in the center of the 4.5x1. It seems like it will just fit. Can you confirm that? If you have calipers, or a mm scale, can you estimate the ID of the 4.5x1 o-ring? Is it oh, 4.5mm ID?GK1 manual shows brass screw oring (#59) as 4.5x1mm (https://www.hubenairguns.shop/colle...en-spare-parts-for-gk1?variant=47416272224588).
I bought some from oringsandmore.com and they're WAY too big. I end up using a 2.5x1.5mm with sanded down OD to fit. Gun holds air now but the brass doesn't go in all the way because the oring is still a little big. Anyone else run into this?
It depends. If I need a bunch of o-rings I'll use the oringstore, or captainoring. Make sure you get a kit, if available, or ensure that you are ordering the correct size! Sometimes I sneak in an item, if I'm ordering from McMaster-Car. Ordering from McMaster means you are getting a bag of 100, so that's practical only for small o-rings, since they're cheap. It's rare to find one place that has what you need.Where do you get your O-rings for the GK1s in the USA from Oring suppliers? Probably will buy a few dozen just in case..
Where do you get your O-rings for the GK1s in the USA from Oring suppliers? Probably will buy a few dozen just in case..
DId you use the brass screw under the loading gate to degas? If so, that is likely your slow leak and a good place to start. Super easy.
I’m assuming that these are all of the o-rings needed. Check pages 11-18 in the owner’s manual. If these are all of necessary o-rings then it would only take someone about 20-30 minutes to sift through them and compile the listed sizes into a an exclusive o-ring list.
GK1 | | | | | | |
Item # | Desc | OD x CS | ID x CS | # | PN | |
1 | NBR90 o-ring | 17 x 1.5 | 14 x 1.5 | 1 | #26 | close valve brass housing |
2 | NBR80 o-ring | 4.5 x 1.5 | 1.5 x 1.5 | 1 | #59 | brass insert screw |
3 | NBR90 o-ring | 11.5 x 1.5 | 8.5 x 1.5 | 2 | #63, #87 | breech seal, pressure tube connector |
4 | NBR90 o-ring | 29.5 x 2 | 25.5 x 2 | 2 | #84 | Pressure tube |
5 | NBR90 o-ring | 9 x 1.2 | 6.6 x 1.2 | 1 | #90 | intake valve cover |
6 | NBR80 o-ring | 7 x 1.5 | 4 x 1.5 | 3 | fill probe | |
7 | NBR90 o-ring | 11.6 x 1.8 | 8 x 1.8 | 1 | #4 | opening valve |
8 | NBR90 o-ring | 6.4 x 1.2 | 4 x 1.2 | 1 | #24 | close valve |
9 | NBR90 o-ring | 4 x 1.5 | 1 x 1.5 | 1 | #41 | Pressure gauge |
10 | NBR90 o-ring | 4.5 x 1.2 | 2.1 x 1.2 | 1 | #57 | Air mag index assist pin |
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Hero! Thank you.
Blush. Wasn't that much work. The first 6 items were on a little scrap of paper that Kelly included with my GK1. (Spare parts bag contents.) So those were easy. Had to go through the manual for the rest of them. Used a calculator to go from OD measurements to ID. ID = OD - 2*CS. Seriously, it took less than 15 minutes.Not sure why your screen name is WobblyHand... —
because you had a very steady hand (and mind!) to assemble —
for the benefit of ALL of us airgun nuts — this extremely helpful table!!
THANK YOU!
Matthias
Haven't found a single source for these. I've had to hunt around. I know McMaster had the probe o-rings (in NBR90). Let me tell you stretching NBR90 o-rings onto the probe is REALLY hard. Most folks would give up and use NBR70. NBR70 will not last as long as they will tend to extrude under high pressure.
