Surface Finish Confusion
Surface Finish Confusion
(OP)
Hello all,
I'm looking to get a steel rod to work with a seal I'm getting. The manufacturer of the seal tells me I need a rod with a surface finish of 16uin Ra or better. A manufacturer of steel rod tells me that he has a precision ground rod that has a tolerance of +0 -0.0005 in. How can I tell if this is good enough?
Thanks!
I'm looking to get a steel rod to work with a seal I'm getting. The manufacturer of the seal tells me I need a rod with a surface finish of 16uin Ra or better. A manufacturer of steel rod tells me that he has a precision ground rod that has a tolerance of +0 -0.0005 in. How can I tell if this is good enough?
Thanks!





RE: Surface Finish Confusion
rp
RE: Surface Finish Confusion
RE: Surface Finish Confusion
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Plymouth Tube
RE: Surface Finish Confusion
all what is said above & also Edstainless is correct, there is a tolerance for seal surfaces. generally like 15-20 micro.
have an independent lab or your inspection department to verify the surface finish & diameter. never rely on your vendor for attributes. It must verified to ensure it's been correctly being mfg.
Mfgenggear
RE: Surface Finish Confusion
Thanks alot for all of the help. It makes sense that the roughness and diameter tolerance are two separate things, just seemed odd that the vendor didn't know much about it. I'll see what else I can find out. Thanks everyone. And good call mfgenggear, I'll be getting a third party to look at the rod after I get it.
Thanks,
-Brammer
RE: Surface Finish Confusion
I've worked with high-vacuum equipment for years in graduate school. The only rods I've ever used with o-ring seals were smooth with no visible signs of machining marks. Make sure you use plenty of vacuum grease.
metalhead