Drill sizes

[Andre V]

Hi,

Can anyone tell me the equivalent metric sizes for the drills used to tap 2-56 and 0-80 holes.

Thanks in advance.

 

[David Wesner]

Hi Andre , for the 0-80 my Tap Drll Chart lists a #56 drill @ .0465 & when taking into consideration the probable oversize hole the drill will make that drill will give you 74% thread. For all following sizes this is the format I will follow

- 0-80 #56 Drill @ .0465 74% thread
3/64 Drill @ .0469 71% thread
1.20 mm Drill @ .0472 probably around 60 % thread (this is the one I would use
1.25mm Drill @ .0492 (probably a little large for tap drill for thread that size)

- 2-56 #51 Drill @ .067 74% thread
#50 Drill @ .070 63% thread
#49 Drill @ .073 49% thread (you can see how fast thread % drops off with just a little bigger hole
1.7mm Drill @ .0669 % ??
1.75mm Drill @ .0689 % ?? (This is the one I would use)
1.8mm Drill @ .0709 % ?? (This one will work too)

Hope this helps

 

[Andre V]

Thanks very much.

 

[David Wesner]

no problem at :thumbup: glad I could help

 

[Andre V]

I had a look at your site. You make some very nice knives. Thanks again