huangyhg

perpendicularity of a frame
i am building a frame per the attached. the questions:
perpendicularity of each side is shown as .06 relative to datum a.
question 1:
a) does this mean that the point shown at each red arrow tip (left side and right side) can each "swing" .060 to the left or .060 to the right? (making for a total allowed arc of 0.120)
b) or does this mean that the total maximum allowed "swing arc" is .060, meaning that the maximum allowed in either direction off of nominal is .030?
question 2:
is there any linkage between the left and right? or is each perpendicularity symbol taken on its own, without regard to the other?
(this would mean that if left and right sides angled out, that the distance between the red arrow tips would be 0.120 (if the answer to 1a above is 'yes'), or 0.060 if the answer to 1b is 'yes')
also, is there a citation or section in y14.5 that describes this?
thank you
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i uploaded the file that goes with the above question, but it does not show on my post - how do i link the uploaded .pdf to my question?
thanks
hi mactruck
without seeing your diagram i would say this:-
if you put a geometrical tolerance of squareness (0.06) of a single feature to a datum then the allowable out of squareness would be +/- 0.06.
so if you have 2 features going to the same datum the maximum parallel error between them would be 0.12.
hope that helps
regards
desertfox
doing the file upload from a different workstation....
another try to upload
i don't know about the citation in asme y14.5, but to answer your questions -
1. a is correct - the total swing is .12 (.06 in any direction).
2. perpendicularity is only taken between the surface which is being controlled, and the controlling datum(s) (i.e. left and right have no bearing on each other unless referenced parallel to one another with one being a datum). the arrow points can shift .06 in any direction, and therefore can be +/- .12 away from each other, off-normal.
hope this helps.
v
mechanical engineer
"when i am working on a problem, i do not think of beauty, but when i've finished, if the solution is not beautiful, i know it is wrong."
- r. buckminster fuller
i agree with vcastro66. the total swing would be .12. each call out should be inspected individually with respect to datum a. you can visually observe this under the asme-1994 std through fig 6-34 - 6-42.
failure is a prerequisite of successful design
mactuck: i can't pull up your graphic, since my company has really strict filters, but as long as you are not exceeding your maximum size tolerance, you can be out of squareness +/-.12 as the other guys have said.
agree with the others. dimensioned as you state, you can be out of square +\-.06 (.12 total swing).
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