Common Errors in GD&T Drawings: Mistakes in Defining Features

[@mathewjadamec4868]

basic dimensions for thickness in side view don't have a size tolerance or form control

[@QwertyCanada]

This is not a complete drawing anyway. The purpose was to show incorrect practices.

[@mathewjadamec4868]

"what is missing?". I think I gave a fair answer

[@niamhbatchford9621]

@@mathewjadamec4868 either a non basic with a tolerance or keep it basic and put a profile tol on the outer face of the flange would do it . i think you had a good question but like they said the drawing is incomplete anyway

[@VictorHernandez-nt3tw]

Good video. Thanks!

[@sajadfilabi9576]

super!

[@gerryvandyk5551]

Using the hole positions as Datum B does bother me. It feels to me that this part will ride on a shaft, and it's most important to ensure the parts features are centered on the shaft. Therefore I'd prefer to see the ID 1.000 +/- .001 to be Datum B. Subsequently the bolt circle diameter and hole positions would be slaved to the bore. Trying to measure the position of the 1.500" boss based on the position of holes that themselves may have up to .0025" deviation seems ambiguous.

[@Gdandtbasics]

That's a great analysis of the decision making process that a designer must understand when selecting their datums for feature control frames. The functional intent of the part should dictate the select of datum features. With out seeing the rest of the assembly in this example we are only operating on assumptions of the final assembly criteria. If the center bore was a clearance bore then it would likely make more sense to use the pattern of holes as a secondary.

[@asaholey]

You forgot to mention that the perpendicularity is correct if it is a datum

[@asaholey]

Your final drawing still has an error. The diameter symbol in the position of 0.188 should be just 0.01, not ⌀0.01.