Finish Requirements
Finish Requirements
(OP)
I have a drawing submitted to me by a vendor and he has noted the finish as:
"ALL MACHINED SURFACES 125 FINISH OR BETTER"
My question is: Is it always assumed that a smoother finish is 'better' or should the wording be:
"ALL MACHINED SURFACES 125 FINISH OR MORE"
or:
"ALL MACHINED SURFACES 125 FINISH OR LESS"
or:
"ALL MACHINED SURFACES 125 FINISH OR HIGHER"
or:
"ALL MACHINED SURFACES 125 FINISH OR LOWER"
I only want to do this once so it's important that I get it right the first time.
Any suggestions?
Thanks, Kim
"ALL MACHINED SURFACES 125 FINISH OR BETTER"
My question is: Is it always assumed that a smoother finish is 'better' or should the wording be:
"ALL MACHINED SURFACES 125 FINISH OR MORE"
or:
"ALL MACHINED SURFACES 125 FINISH OR LESS"
or:
"ALL MACHINED SURFACES 125 FINISH OR HIGHER"
or:
"ALL MACHINED SURFACES 125 FINISH OR LOWER"
I only want to do this once so it's important that I get it right the first time.
Any suggestions?
Thanks, Kim





RE: Finish Requirements
http://www.mfg.mtu.edu/cyberman/quality/sfinish/
The note should read "ALL MACHINED SURFACES 125 FINISH".
RE: Finish Requirements
RE: Finish Requirements
Also, after I think about it, depending on the part, I don't think you would want "All machined surfaces...". There may be some surfaces you don't care what finish they are. Maybe "All machined surfaces...except where noted".
RE: Finish Requirements
My understanding, with which my Machinery's Handbook agrees, is that the number attached to the surface finish symbol is the maximum allowable roughness. You have the option of applying two numbers representing the MAX and MIN values for roughness for when you want the surface to be rough.
JHG
RE: Finish Requirements
I agree that's the best way to handle it - thanks both of you. One other thing - the phrase in the notes, according to ANSI is "UNLESS OTHERWISE SPECIFIED..." followed by the note. I've even seen it as "UOS" on Hamilton Standard drawings. The spec says that it should be the first part of the note.
Thanks again,
Kim