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Proper GD&T callout for countersink holes for flat head screws

Proper GD&T callout for countersink holes for flat head screws

Proper GD&T callout for countersink holes for flat head screws

(OP)
I am struggling with applying GD&T to #6 flat head screw holes.  I've attached the applicable drawing that I'm working on.  The mating part has press-fit inserts that the screws thread into.  I am looking into using "floating" inserts that allow for +/-0.015", but they are larger and packaging into the design may be an issue.  I have the countersink called out RFS, but if I switch to the floating insert can I call it out as MMC?

Is there anything else that I am missing?  Thanks!

Here's the link to the currently spec'd insert:  http://select.pemnet.com/interactiveSearch.php?FASTACT=ISEARCH_PRODUCT2&FPRODUCTID=3409&PAGEID=
Here's the link for the floating inserts that I'm trying to package:  http://www.pemnet.com/fastening_products/pdf/a4data.pdf

 

RE: Proper GD&T callout for countersink holes for flat head screws

Electret,

   A countersink centres your screw.  MMC does not affect location.  I agree with your idea of using floating fasteners.  

   Usually, I specify holes and positional tolerances on the assumption that fabricators can easily do Ø.010".  If I cannot make at least one hole float, as in your case, I specify positional tolerances of Ø.005".  

   If your part is sheet metal and your holes are coming from a bend, you cannot do any better than ±.015" from the bend.  You will have to re-think your design.

               JHG

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