Limiting Hole to Hole Size Variation

[JCReynolds79]

Hi all,

Numbers of holes , equally spaced on a PCD. The size of the holes can be quite loose, say, +/- 0.2mm. But what I am trying to think of is a way to control the variation of hole sizes. In sentence speak, Holes can be +/-0.2 but each hole must be within 0.05 of each other.

e.g. dia 10 +/- holes specified gives a hole size target of 9.8-10.2. Lets say the first hole we make is 9.9. I want to ensure/control/specify that all other holes in the pattern must be within +/-0.05 of first hole. So all other holes must now lie within range 9.85-9.95.

Its like I want a composite tolerance on the hole size....

Thanks!

Regards,

Jon Reynolds

 

[PeterStock]

To replace the average with the value of one particular hole, call out that hole with the normal dimension i.e. DIA 10+/-0.2 (my personal preference would be the limit dimension). Make that hole datum G.

Change the note to:

6 NOMINAL VALUE OF DIA N IS TO BE THE MEASURED VALUE OF DATUM G.

Peter Stockhausen
Designer / Checker

 

[PeterStock]

My checker brain just told me to make that SHALL BE

Peter Stockhausen
Designer / Checker

 

[drawoh]

Interesting thread. Overall, I would say that the OP's requirement for "consistency of hole size" would best be specified in the form of a note.

The OP's requirement is weird. I cannot see why I would do this. I cannot see why the standard has to cope with it, since a note will work. The more esoteric stuff you add to the standard, the more likely it is that people will not understand it.

Dynamic profile sounds like a useful concept. I can see myself using it five or ten years from now, when the next Y14.5[ ]update comes out, and a reasonable number of fabricators and inspectors have learned about it. I almost missed the symbol when I first inspected 11[‑]37.

--
JHG

 

[3DDave]

I just want to see a sensitivity analysis that's done to set the tolerance limits.