> For .035 +.004 -.001 finished holes, we have a pad size of .050
>  What pad size is required to meet annular ring requirements
>  per MIL-P-55110 ???
>
The easy answer is 0.002 for a type 3 board.  But it's really more
detailed than that. I use the following formula to determine the
minimum anular ring.

(Finished hole size +0.005)+(2X min.annular ring)+(a manufacturing
adder of 0.014)=minimum land diameter

So, for your example
0.035+0.005+0.004+.014=0.058 diameter pad minimum required.

I'd say your present pad is a bit undersized using standard
production processes.

Tom Hybiske
General Atronics Corp.

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