Datums coaxial A-B
Datums coaxial A-B
(OP)
Hi I'm trying to clean up Gtol prints for different engineers but I don't recommend changes until I have confirmed that the changes I recommend follow standard. I couldn't find this in the book specialty
Ok I have an assembly situation
this is what Eng1 has listed
two bushings space 24plus inches apart welded in place (Intended to be coaxial). the left bushing is Dia x.xxx position .xxx mmc A, creating Datum -A1- (attached to feature frame). Right bushing is Dia x.xxx position .xxx mmc A creating Datum -A2- (attached to feature frame). he then uses these two bushings as Datum -A- in other feature frames.
From my understanding the left side should be dia x.xxx creating datum -A- and right side should be dia x.xxx position .xxx mmc A, creating datum -B- and all future feature frames should call out A-B to establish the two bushing as a datum.
my assumption is Eng1 is trying to use the datum target concept A1, A2, Etc using the datum flag to create a datum thru the two bushings. I believe this is incorrect application. plus he is referencing the datum to itself
Let me know if I'm off on this
RE: Datums coaxial A-B
RE: Datums coaxial A-B
What standard are you working to? Y14.5-2009 or an ISO standard?
RE: Datums coaxial A-B
RE: Datums coaxial A-B
If using datum targets, then you can get into the letter/number combination.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: Datums coaxial A-B
RE: Datums coaxial A-B
If the top 4x diameters are one size and the bottom 2x are another size the simplest thing to do would be reference the bottom 2x pattern as datum A (no datum references in position tolerance), top 4x pattern as datum B (reference datum A in position tolerance) and reference it as A|B in the FCF on the controlled feature in the center. Is there any reason you wouldn't want to do this?