I'm looking for some drill and tap sets, just the specific sizes not a whole kit full. I need 6-32 and M3, for building a custom case. I found 6-32, and also 3mm, but here is where I'm confused. This is the site I found 6-32 on, and they have 3mm, is 3mm M3? Also it says 3mm Tap 3mm Drill, if it's an M3 tap, shouldn't the drill bit be 2.5mm?
It's not actually a 3mm drill. It is a matched pair with the 3mm tap. The drill bit is slightly smaller and is only for use with that tap.
yes M3 is 3mm being "Metric 3" i think if there is more than one number ie 3mm by 1.5mm the second number means a thread pitch oif 1.5mm and i think for 1mm pitch they just leave it out cause it's the generic pitch. people please tell me if I'm wrong also
the 3mm is the clearance hole, and the maximum diameter of the thread. The tapping drill makes a hole slightly smaller, and the tap taps it (obviously) so that a screw with a 3mm thread on it will go through it. So a M3 tapping drill would probably be about 2.6mm, depending on the depth of the thread.
Okay so I've been looking around... According to this and many other sites, for a 6-32 tap, you need a #36 bit. Problem is, I can't find #36 bits, just fractional ones? Also, for an M3 tap, you need a 2.5mm bit, does that fit into the M(x) scheme? Or will the bit just be called 2.5mm?
If you go to a HD or other major hardware store, they often have the tap and associated bits in a combo package, or individually in the immediate area. The ones that I've bought have the matching size on them, i.e. that #6 tap would have "uses #32 drill bit" and the #32 bit would have "use with #6 tap" written on the package. I've even seen a decent selection at a local ACE hardware. If you simply can't get them locally, try mcmastercarr.com. They've got EVERTHING!
Personally I would use 2.6mm but then thats just because of the taps I've used wern't very good. Its just a normal 2.5mm drill to make the "tapping hole" (2.5mm in diameter), which you then tap with the tapping bar.
