iso 2768

huangyhg

iso 2768
i am trying to see if i am missing something in the way we have dimensioned parts and their respective tolerances.  our title block calls for machining tolerances according to iso 2768 mk.  we have many cut outs in plates sized say 100 x 100, we have matching boss inserts sized 100 x 100, is there any implied tolerancing between these to insure there is no inteference.  it would see according to what i have seen that there is in fact a lot of room to these two discrete parts to fall within the tolerance range but not fit together for welding.  last time i checked we would normally want essentially a locational clearance fit for accurate positioning and ease of assy for welding.
tap
in your case, you will need to specify a tolerance to be sure that there is no intereference.
i suppose you could also call out a tolerance class of fit, but i don't know if they only apply to cylindrical items.
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ben loosli
cad/cam system analyst
ingersoll-rand
thanks for the reply, we are "supposed" to be doing complete build to print packages, the example i was refering to was signed off on as a rev "0" package for construction (done in another office) and is a poster child for how not to dimension.  i just wanted to make sure i was not missing any thing we do in fact need to add over/under size tolerancing if we do not want fabricators having parts that must be reworked to fit.
tap