flatness tolerances for "stock" material
flatness tolerances for "stock" material
(OP)
Several people at my company always put flatness tolerance callouts on faces that are indicated as being "stock" dimensional thickness and then use them as a datum, typically Datum A. We're not talking sheet metal here either, we're talking stock anywhere from 1/4" plate to 1" bar stock. I always wonder if that's "legal". It seems that we're telling the machinist to use the stock material, but ensure that it meets some flatness tolerance. In some cases the flatness is specc'ed as 0.2mm for 1/4" thick aluminum plate over a distance of a meter! Other times they call out flatness of 0.2mm for a 3/4" stock thickness piece only a couple of inches long and call that out as Datum A. Is it right to call out a flatness tolerance on material listed as "stock".
Thanks,
Courtmann
Thanks,
Courtmann





RE: flatness tolerances for "stock" material
RE: flatness tolerances for "stock" material
Any other responses on the appropriateness of flatness and perpendicularity tolerancing finished pieces largely using stock dimensioned material would be appreciated.
RE: flatness tolerances for "stock" material
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: flatness tolerances for "stock" material
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: flatness tolerances for "stock" material
Chris
SolidWorks 11
ctopher's home
SolidWorks Legion
RE: flatness tolerances for "stock" material
Thanks
RE: flatness tolerances for "stock" material
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
http://www.gdtseminars.com
RE: flatness tolerances for "stock" material
On the drawings I'm doing/correcting I've started calling out flatness of 1mm in the free state for the longer 1/4" plate pieces and eliminating flatness tolerance callouts entirely where "stock" thickness callouts also exist.
Thanks,
RE: flatness tolerances for "stock" material