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

[Electret]

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

 

[drawoh]

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

 

[KENAT]

thread1103-255441 delt with the fixed-fixed situation in some detail.

Posting guidelines faq731-376

http://eng-tips.com/market.cfm?

(probably not aimed specifically at you)
What is Engineering anyway: faq1088-1484​