what is"125 finish on all machined surfaces"

[nadine1314]

I have a inquiry of "7/16 flared tuve nut",the customer asked "125 finish on all machined surfaces",I don't know how to understand 125 finish.

Thank you

 

[MikeHalloran]

I'd guess 125 micro-inches RMS, which is fairly coarse. Most tube fittings are far smoother than that. But you need to ask the customer for clarification, not me.



Mike Halloran
Pembroke Pines, FL, USA

 

[nadine1314]

thank you Mike,I'd like to hear more from other persons.

it is too late for you.Have a good rest.

 

[TheBlacksmith]

My interpretation is the same as Mike's.

 

[patdaly]

Same here, probably an older Engineer specing it.

I do it all the time when I dont care what the finish is.

125 F.A.O. signifies the same.

 

[TStaples]

In the engineering world in which I operate, it is customary to place a general note on component prints to indicate an acceptable finish on on non-critical surfaces, or surfaces that aren't explicitly called out (e.g an o-ring groove, or bushing bore.) In automotive, where Sensible unIts are used, the general note would be for a 3.2 finish, which means 3.2 microns rms max. By having the general note covering everything that isn't explicitly called out to a better finish, there is an agreed upon value for QC checks. It's prevents your supplier from dropping a part into a rough textured floor, and just blindly picking it up and throwing it back into the delivery box, even though it now has a big gouge or scratch on one surface. If you don't have some kind of general spec on the print, then it's a good part.

125 microinches is equivalent to 3.2 microns, and is very easy to meet with most maching, blanking, drawing, and even some forging processes. It is the Engineer's equivalent of CYA!

-Tony Staples

http://www.tscombustion.com