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Wish I could find a tool or two to install 1.5 x 4 NBR90 o-rings on a 7mm probe. Seems like I need 15 hands. Anybody know something that would work?
 
@WobblyHand
I have made a long tapered cone, with a polished surface, to install O-rings on small diameter shafts. The tool had a major diameter .010 " larger than the shaft and had a counterbore in the end, to receive the shaft end (for alignment and to take the chamfer out of play. I used O-ring lubricant and "screwed" the O-ring up the taper. By "screwed" I mean that I rotated the cone and used a fingernail to push the O-ring along.
If the O-ring rolls, inside out, it will likely break. If the cone doesn't work, get lower Durometer O-rings.
 
The other trick is some Teflon lacing tape. You thread it through the O ring, and then use it to allow you to pull the thing over and through grooves.
Like nuclear powered dental floss.

Sent from my SM-S911U using Tapatalk
 
@WobblyHand
I have made a long tapered cone, with a polished surface, to install O-rings on small diameter shafts. The tool had a major diameter .010 " larger than the shaft and had a counterbore in the end, to receive the shaft end (for alignment and to take the chamfer out of play. I used O-ring lubricant and "screwed" the O-ring up the taper. By "screwed" I mean that I rotated the cone and used a fingernail to push the O-ring along.
If the O-ring rolls, inside out, it will likely break. If the cone doesn't work, get lower Durometer O-rings.
Thanks, interesting idea. NBR70 is known to extrude at 5000 PSI, OEM is 80, didn't see any, so bought 90.
 
The other trick is some Teflon lacing tape. You thread it through the O ring, and then use it to allow you to pull the thing over and through grooves.
Like nuclear powered dental floss.

Sent from my SM-S911U using Tapatalk
Oh, I like that idea. Don't have anything like that, except maybe for teflon like dental floss, which might work! Might not avoid the three ring circus, but will make it easier to get the o-ring out of a groove that it shouldn't be in.

Think I will put the probe back in the lathe chuck, so at least I don't have to hold it, too many degrees of freedom!
 
The other trick is some Teflon lacing tape. You thread it through the O ring, and then use it to allow you to pull the thing over and through grooves.
Like nuclear powered dental floss.

Sent from my SM-S911U using Tapatalk
Can't even seem to get this o-ring over the end at the moment. If it was on the rod, I bet your idea works great.
 
McMaster has NBR (Buna-N) in that size in 70 and 50 durometer.


If you haven't checked McMaster . . .
 
McMaster has NBR (Buna-N) in that size in 70 and 50 durometer.


If you haven't checked McMaster . . .
70 durometer will probably extrude at 5000 PSI. 50 will definitely blow out under pressure. I wanted 80, but they don't carry that. Perhaps a variation of this picture may work. Skinny end is 4mm, fat end is 7mm, the diameter of the probe is 7mm. Have a locating pin, in case. Some lube and maybe some additional luck. Already made 3 tools just to fab the HPA probe, I guess one more to assemble the o-rings won't hurt me. Lubed small o-rings are hard to grab on to!
oring_tool.jpg
 
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