Sliding fit using GDT

[ShlomoB]

How the standard combinations of fits (as H7/g6 etc) can be used combined with orientation gdt? For example perpendicularity. As if I use the standard size for shaft and add the perpendicularity, I screw up the standard hole dimension (in virtual condition).

 

[3DDave]

It's a Feature Control Frame, for ASME Y14.5; there is no Geometric Dimensioning.

As if I use the standard size for shaft and add the perpendicularity, I screw up the standard hole dimension (in virtual condition).

Care to share the diagram and calculations you have used so far? Please use the Image button if possible for any pictures.

 

[Burunduk]

Shlomo,
limits and fits are mainly useful for considering how external and internal mating features would fit when no constraints are applied (such as at manual assembly where you just insert a pin into a hole by hand without any pre-established mutual orientation or location between the parts). If these are not the primary mating features and the virtual condition is considered you can no longer count on the level of clearance or interference indicated by such classifications as "clearance fit", "transition fit", or "interference fit" and their sub-types (such as "sliding fit").

 

[ShlomoB]

@Burunduk
Yes that's what I thought. I mean, all the information that exist (on books and the web) about these standards of fits don't take into account the orientation constraints.
As if you apply some say perpendicularity or parallelism the virtual conditions will deviate from the standard.
Thanks.

 

[3DDave]

B, you and ShlomoB could get together and have lunch. Possibly tell him all about what virtual condition means and why there's no standard for virtual condition in standard fit documents.

 

[Burunduk]

Good suggestion. Virtual Condition, limits and fits and product definition standards are fun to talk about while wiping Hummus.

 

[CheckerHater]

Back in good old times using ISO standard tolerances and fits would automatically imply Envelope requirement.

New edition of ISO 286 removed that, but you still can specify Envelope requirement individually if you want your size to also control things like form and orientation.


"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future

 

[Burunduk]

CH,
Since when does the Envelope Requirement (circled E) controls the orientation of a feature or any feature to feature relationship?

 

[CheckerHater]

My apologies.

"For every expert there is an equal and opposite expert"
Arthur C. Clarke Profiles of the future