TP callout for two bearing counter bores
TP callout for two bearing counter bores
(OP)
Hi there,
I need your opinion on the case below:
Problem: A buterfly valve with a shaft goes thru both side of the wall. Each side has a bearing bore callout.
1. The hole for the shaft is a thru hole with diameter A +/- tol with a datum A callout.
2. The bearing bore on the right states 2 X diameter +/- tol (for two bearings bores) with a TP of .002" to datum A.
3. They call out a datum C on the bearing bore on the left of the body with a TP of .003" to datum B-C.
Question:
a. Is the callout in item 3 above valid? and good control?
b. Does the 2X diameter +/- tol with a TP of .002" to datum A in item 2 above apply to both bearing bores, regardless the callout in item 3 above? In other word, the callout in item 3 above is NOT REQUIRED.
Your earliest help is appeciated.
Uptick.
I need your opinion on the case below:
Problem: A buterfly valve with a shaft goes thru both side of the wall. Each side has a bearing bore callout.
1. The hole for the shaft is a thru hole with diameter A +/- tol with a datum A callout.
2. The bearing bore on the right states 2 X diameter +/- tol (for two bearings bores) with a TP of .002" to datum A.
3. They call out a datum C on the bearing bore on the left of the body with a TP of .003" to datum B-C.
Question:
a. Is the callout in item 3 above valid? and good control?
b. Does the 2X diameter +/- tol with a TP of .002" to datum A in item 2 above apply to both bearing bores, regardless the callout in item 3 above? In other word, the callout in item 3 above is NOT REQUIRED.
Your earliest help is appeciated.
Uptick.





RE: TP callout for two bearing counter bores
Hope to hear from you soon. Thanks
Uptick
RE: TP callout for two bearing counter bores
Please post a sketch its far easier to see and follow rather than your description.
desertfox
RE: TP callout for two bearing counter bores
The GD&T forum is the correct location for this question.
"Good to know you got shoes to wear when you find the floor." - Robert Hunter
RE: TP callout for two bearing counter bores
The shaft bores are tertiary at best.
Mike Halloran
Pembroke Pines, FL, USA
RE: TP callout for two bearing counter bores
Sorry. I posted in the wrong place before I posted this here.
Mike: The datum A (the shaft thru hole) is already tight to the butterfly bore which I did not present here. Now the issue is the bearing bores are controlled the A. I wont to know if the callout is correct (valid). I know the total runout for C to B is the best, but does this one (TP callout) work?
Thanks,
Where is KENAT?
Uptick.
RE: TP callout for two bearing counter bores
Mike Halloran
Pembroke Pines, FL, USA
RE: TP callout for two bearing counter bores
RE: TP callout for two bearing counter bores
RE: TP callout for two bearing counter bores
Working the job that pays my bills. I'm not overly familiar with valves and didn't follow your description well enough to comment.
forum1103: Drafting Standards, GD&T & Tolerance Analysis thread1103-279665: True position callout
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: TP callout for two bearing counter bores
I think you can't reference B&C to themselves which is what you appear to have done.
What I would do is have B&C as your datum and then use runout of the bore datum A (thru hole) to the datum B&C.
desertfox
RE: TP callout for two bearing counter bores
Further to my last post your tolerance figures should actually be derived from the clearance between bearing internal diameters and shaft diameters, ie when the bearing housing holes are misaligned and the bearings and shaft have minimum float, you should still be able to assemble all the components.
desertfox