Certainly the threads (UNF 9/16-18 I think) have to be the same size else a standard hose fitting would not screw on to it. I don't think going to a SP splined nut would be a good idea for someone who got rid of his SP wrench. 
Atomic M1 jam nut size?
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OP
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Certainly the threads (UNF 9/16-18 I think) have to be the same size else a standard hose fitting would not screw on to it. I don't think going to a SP splined nut would be a good idea for someone who got rid of his SP wrench.
So true, when I had a stable of G250s was trying to find an alternate to the splined nuts, from memory we had a thread running discussing the use of Atomic jam nuts and G250V jam nuts. IIRC the G250V ones were too long and I have a niggling feeling there was an issue with Atomic jam nuts too. I'll try to find the thread.
If I can get some 11-16 nuts I'll be happy as they are the same size as my Apeks, "standardization" and all that.
This thread would win the award for the most nuts used.
OP
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I don't even like nuts.
eelnoraa
Contributor
Like couv said, the thread size is standard LP hose thread. I happen have these laying around after service. Here is some measurement number for the width:
G250V: 0.479"
M1 new style: 0.515"
M1 old style: 0.515"
B2/regular Atomic: 0.439"
HOG classic: 0.234"
A few observations:
0. I hate proprietary fitting jam nut on G250V that need a dedicated tool to operate.
1. I really think M1 old style is a better heatsink. weight about the same as the new style, but much more surface area.
2. For Atomic, the inlet tube length is the same between B2 and M1. But jam nut vs heatsink width is different. Thing works just file. So it makes me think that there is some margin on the width to play with. For this reason, if I round out my G250v jam nut, I will just give Atomic regular jam nut on it, only 0.04" narrower.
3. I happen to have a HOG laying around. It has a very narrow jam nut. With this width, it won't work on the Atomic 2nd stage. I didn't try it on G250v because I don't want to muscle with that jam nut.
G250V: 0.479"
M1 new style: 0.515"
M1 old style: 0.515"
B2/regular Atomic: 0.439"
HOG classic: 0.234"
A few observations:
0. I hate proprietary fitting jam nut on G250V that need a dedicated tool to operate.
1. I really think M1 old style is a better heatsink. weight about the same as the new style, but much more surface area.
2. For Atomic, the inlet tube length is the same between B2 and M1. But jam nut vs heatsink width is different. Thing works just file. So it makes me think that there is some margin on the width to play with. For this reason, if I round out my G250v jam nut, I will just give Atomic regular jam nut on it, only 0.04" narrower.
3. I happen to have a HOG laying around. It has a very narrow jam nut. With this width, it won't work on the Atomic 2nd stage. I didn't try it on G250v because I don't want to muscle with that jam nut.
Scared Silly
Contributor
Late to the party but the old style and new style heat sinks I have are both 0.81 inches or 20.55mm so a 13/16 would work. The std. jam nut is 11/16.
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