angle and its true position
angle and its true position
(OP)
Could I add posision tolarance to the angle which desribe slots width?
Thanks in advance
Thanks in advance
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angle and its true position
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RE: angle and its true position
Peter Stockhausen ://www.lin kedin.com/ profile/vi ew?id=3006 4526&t rk=tab_pro
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RE: angle and its true position
Certainly position controls can be used with slots, but I'm not sure what you're trying to do with the angle.
Generally the position FCF's are based on the overall length and width of the slots, I'd think the angle would be basic.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: angle and its true position
I may be wrong but I assume pewex is thinking about applying positional tolerance FCF to an angle describing countersink like hole.
RE: angle and its true position
RE: angle and its true position
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: angle and its true position
Your angle defines a feature of size, therefore, you can apply a positional tolerance.
This will control the rotation of your feature with respect to some angle reference feature you specify as a datum. Is this what you want to do?
RE: angle and its true position
I would not say 7-16 is similar situation to this case because walls for the slots on 7-16 are nominally parallel. This allows using positional tolerance.
For OP's case I would suggest applying profile of surface callout to whole outline of the shape (maybe with ALL AROUND symbol attached to the leader of FCF). IMO angled walls can not be considered as a feature of size and positional tolerance should not be applied here.
I am starting to worry that can of worms entitled 'Feature of size definition' has just been opened again:)
RE: angle and its true position
Belanger,
I don't have the current standard in front of me, but can you double-check that 6-14 is the figure you mean to reference for the 1994 version? It doesn't seem applicable to me, showing profile between two points.
RE: angle and its true position
But yeah, if the OP is talking about a slot that has a varying width, I'd probably steer clear of using position.
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: angle and its true position
A 1) wedge or 2) cone is now sanctioned by Y14.5-2009 as a datum feature, which would have a "wedgical"
Especially since center planes on even a normal slot are not so easy to find (cmm software programmers provided capabilities for cylindrical features pretty well, but not yet for slots, "slabs", cones or wedges), I agree with those that have said that a profile tolerance, with basic dimensions to define the center of the zone/true profile would probably be better in this case... At least until software is quite a bit better and standards advance a bit more.
Dean
www.d3w-engineering.com
RE: angle and its true position
Do you know why there is not a single example in Y14.5 that would show position tolerance applied to an angle dimension?
Isn't position of conical / "wedgical" features common enough in reality to deserve showing on at least one figure in the standard?
I am asking not only by curiosity, but also because I have really no idea if such callouts are legal or not. Since there is nothing in Y14.5 (and as far as I see in Y14.8), I have nothing that would scatter my doubts. Is there any other document that could help?
RE: angle and its true position
Could you get away using linear dimension instead of angle?
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(The picture is intentionaly incomplete)
RE: angle and its true position
IMO your proposition sounds good according to Y14.5
Anyway I decided to not use true position, but locate slots on parts perimeter by toleranced angles. Slots are defined by +/- angle like it is on my sketch and controled by +/- radius.
The question is still open. I didn't find the answer in any document I know.
Thank you all gentlemen for quick response and I look forward to hearing some good news from you.
RE: angle and its true position
You're quite right that Y14.5 and Y14.8 don't really provide direct support for a position tolerance for cones or wedges. I also don't know of any other standard that would help.
I think it's logical enough and could be done, but unless/until a new revision of either Y14.5 or Y14.8 supports it better, maybe with a flag note to explain that the tolerance applies to the cone's axis or wedge's center plane..?
pewex,
Toleranced angles don't mean much... I hope you might reconsider profile of a surface. I understand that we're all operating with suppliers that may not be comfortable with profile though.
Dean
www.d3w-engineering.com
RE: angle and its true position
Of course, I've been wrong a lot lately so feel free to correct me while I wallow in my own inadequacy.
Powerhound, GDTP T-0419
Engineering Technician
Inventor 2010
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RE: angle and its true position
Thanks for reply.
It seems I would have to wait another 10 years or more until proper examples appear in updated revisions of Y14.5 or 14.8 and clear my doubts
powerhound,
I agree with you that feature of size definition in Y14.5M-1994 is not including conical features. IMO modified 2009 definition is not doing it as well, but this is another story.
Actually I believe whole confusion stems from inprecise FOS definition in the standard. I think such essential concept for GD&T should be supported by at least several graphical examples that would help in better understanding the intent of Y14.5 committee members.
Without this we have a situation that every GD&T user has its own interpretation of FOS definition and noone knows for sure what is really going on.