By making the angle of a chamfer basic does this mean the angle has to be "Perfect"?

There is a discussion here about the validity of showing the angle as a basic and using the tolerance block in the drawing title block to control the chamfer size. Thus allowing angle variation within the limits of the depth of chamfer.

Is this a valid way of controlling the angle of the chamfer?

One discussion is to have the angle tolerance dictated by an angular tolerance in the title block.



Our ANSI Y14.5-1994 book does not discuss this.

Any help would be appreciated.

Tony

ANYONE?

The purpose of making a dimension "basic" is to exclude it from the title or drawing block tolerance.  So, assuming the block tolerance applies to a chamfer defined by basic dimensions is incorrect.  

If you use basic dimensions, then you would need to also apply an appropriate geometric tolerance (probably a profile tolerance) to define the allowances for the surface.

ASME Y14.5M-1994 defines several methods for specifying a chamfer in paragraph 1.8.15 (page 14) and Figures 1-41, 1-42, 1-43 and 1-44. (pages 17-18).  All of the examples illustrated would default to the block tolerance as long as they were not enclosed in a box.  Select the method most appropriate for your application.

Hope this helps

GDT GUY

Thank you! This is what my associate and I were thinking but without our '1994 book (lost but another one on its way) we could not prove or dis-prove.

Thank you again!

Tony