hole pattern : controlling hole-hole position
hole pattern : controlling hole-hole position
(OP)
Hi all,
Here I have requirement , assume a rectangular block which has pattern of holes on it.
The pattern of hole is used to establish the datum. with respect to the pattern of holes the edges of the block needs to be located. now the question comes that before using the pattern of holes as datums , i need to control the orientation of hole axis to the bottom surface- this can be done by applying the perpendicularity control to holes. Along with the perpendicularity control i need to control the hole-hole distance as well.
In ISO GPS standard, if we use a perpendicularity control to the pattern of holes, the spacing tolerance between the holes is also defined. but in ASME it is not
there is a similar example fig 4-22 of 1994 std, can this be used? does this control the hole to hole distance of the pattern.
can anyone help me?
Here I have requirement , assume a rectangular block which has pattern of holes on it.
The pattern of hole is used to establish the datum. with respect to the pattern of holes the edges of the block needs to be located. now the question comes that before using the pattern of holes as datums , i need to control the orientation of hole axis to the bottom surface- this can be done by applying the perpendicularity control to holes. Along with the perpendicularity control i need to control the hole-hole distance as well.
In ISO GPS standard, if we use a perpendicularity control to the pattern of holes, the spacing tolerance between the holes is also defined. but in ASME it is not
there is a similar example fig 4-22 of 1994 std, can this be used? does this control the hole to hole distance of the pattern.
can anyone help me?





RE: hole pattern : controlling hole-hole position
4-22 for sure controls perpendicularity of holes relative to datum A as well as hole-to-hole spacing.
May I know which ISO standard is a base for you to say that perpendicularity applied to a pattern of holes controls hole-to-hole spacing too?
RE: hole pattern : controlling hole-hole position
sure i can send you the snap shot when i go to office tomrw. i dont remmember the std number.
RE: hole pattern : controlling hole-hole position
I just couldn't recall and thought you could help me right a way.
RE: hole pattern : controlling hole-hole position
Frank
RE: hole pattern : controlling hole-hole position
Strange, isn't it?
RE: hole pattern : controlling hole-hole position
That really is, I am not crazy about that! It is almost like spite, "you guys control perpendicularity indirectly with position so we will control location indirectly with perpendicularity".
Frank
RE: hole pattern : controlling hole-hole position
I agree with Frank. It seems to mess with the hierarchy of things. What if you really only cared about perpendicularity, and not at all about location of the holes?
John-Paul Belanger
Certified Sr. GD&T Professional
Geometric Learning Systems
RE: hole pattern : controlling hole-hole position
It applies every time, not only when a pattern is referenced as a datum feature
RE: hole pattern : controlling hole-hole position
Do not use word "location" - it is risky today. It is only spacing
RE: hole pattern : controlling hole-hole position
That is exactly the kind of thing that bothers me, it is like someone doesn't think the possibilities all the way through (or from my experience, they have simplified the problem so they don't need the extra options, which we inevitably need in real world applications). This is just like the battle to have the option to orient patterns of features (as a pattern, not just features normal to a face) as a refinement of a pattern location.
pmarc,
I thought "location" was the general term we could use?
Frank
RE: hole pattern : controlling hole-hole position
"If you have been looking at ISO 2692 on the Maximum Material Principle, and you think you have spotted an error, you are probably right. This standard has numerous errors in the text and diagrams - use it with caution." Iain Macleod Associates
I hope they are correct!
Frank
RE: hole pattern : controlling hole-hole position
pmarc, I should have added this at the end of my reply to you :)
RE: hole pattern : controlling hole-hole position
They are correct. I have an article in my hands written by one of the members of ISO GPS TC213 committee which says that Annex A contains some significant errors and should be used with caution. Unfortunately it has not been specified which specific points, figures or notes are vague. Maybe it has something to do with this perpendicularity thing.
I will try to ask him - let's hope he will clarify exactly where the problem is.
RE: hole pattern : controlling hole-hole position
I got a response from the member of ISO TC213 committee. There is a mistake in the latest edition of ISO 2692 standard. Perpendicularity does not (cannot) control spacing between features within the pattern.
RE: hole pattern : controlling hole-hole position
Thank you, Maybe there is a god and he does not hate the ISO!!
RE: hole pattern : controlling hole-hole position
I have already created few drawing based on this. I think I need to relook into this. :)
RE: hole pattern : controlling hole-hole position
Frank