Geometric demensionig and tollerancing

[mikewesterfield]

Is anyone good with GD&T. I am trying to put GD&T on a v-belt pulley. The problem is we are getting ap ulley in from a vendor where the set screw isn't radial. (it doesnt hit the center of the shaft) There are 2 set screws on the pulley that are perpendicular with each other. One of which is on the keyseat, the other being the 90º from it, on the centerline. At least it is supposed to be.

 

[drawoh]

mikewesterfield,

Are you tring to apply a tolerance, or interpret one?

If you trying to interpret an existing tolerance, make sure the drawing has a reference to ASME Y14.5M-1994 or its ISO equivalent. Otherwise, the tolerance is not based on a standard, and cannot be interpreted.

If you show your tapped hole on the centre line without a positional tolerance, I think you are on your own. I am not sure how I would interpret that under ASME Y14.5M-1994.

If this were my drawing, I would specify a geometric tolerance, and call up the pully face, the bore and the top surface of the keyway as my datums (data?). My tolerance would be fairly sloppy, since probably, I don't care that much about where the set screws go.

Getting tapped holes into the right place cannot be that difficult. Regardless of GD&T and your drawing, perhaps you need a new vendor.

JHG