O.T. Tools Tap and Die set Help Please

[highflier]

OK 1 last question.
Tap set showed up today, no drill set but thatis no big deal as of FLM alredy drill and half taped the hole :)

It is obvious that I need the 4MM tap not the 3MM No big deal just FYI for any others that read this thread.

The taps are not label course or fine. THe 4MM are labeled
4MM X .75
4MM X .7

I for this task I am sure it will work either way... but for future knowledge which is the correct order to run them into the hole. .7 first then the .75?? At least that would be my guess if nobody answers me.

Highflier

I don't think metric works like that. For metric, the 2nd number is the thread pitch I believe. RC 4mm screws are listed as 4mm x .7, so thats the tap to use. The .75 will not fit the threads of the .7 based screws. You might get away with it fitting in soft alum, but in something harder, you'd feel it bind.