drill bits

[watch_art]

I need to order some drill bits to match my new 9/16 and 5/8 taps. Yes I'm going to make some BIG pens.

Should I go 1mm under the metric size and just get that?

So for 9/16
13 or 13.5mm drill bit?

and for 5/8
14.5 or 15mm?

Thanks!

 

[jd99]

Try this:

Tap Drill Size Calculator -- Technical Notes

 

[watch_art]

Thanks - I can't get anything to do anything though. Will have to play with it later.

 

[Chthulhu]

According to Machinery's Handbook:

9/16"-12 uses a 31/64" drill
9/16"-18 uses a 33/64" drill
9/16"-27 uses a 17/32" drill

5/8"-11 uses a 17/32" drill
5/8"-12 uses a 35/64" drill
5/8"-18 uses a 37/64" drill
5/8"-27 uses a 19/32" drill

 

[watch_art]

thanks!