Hole drill diameter and tolerances for press fit of GM3 module

anand_i

I'm attempting to design a PCB with CAB006M12GM3 module. This is a press-fit module and I've gone through the application note CPWR-AN41. Table no.1 in page 3 specifies that the drill hole diameter should be 1.21 to 1.24mm. However, talking to the PCB fabricator, it looks like they use the metric drill bit where drills are available in increments of 0.05mm. So the fabricator can use either 1.2mm drill or 1.25mm drill. What is the rationale for specifying 1.21mm to 1.24mm? This does not seem be achievable by fractional inch drill bit system either.

Also, the finished hole size should be in the range of 1.08mm-1.18mm, which requires a tolerance of +/-0.05mm. However searching through various PCB fabs online, it looks the minimum tolerance for a PTH hole is +/-0.075mm. Is the tolerance mentioned by the application note achievable in manufacturing?