Drill size for tap?

[p8ntbal4me]

mine has a chart as well but it has a 60% thread sixe and 75% thread size collum so i havent goetten a chance to understand it exactly yet

-matt

I was told to think of it this way: use 60% when the threading and set needs to be critical. Such as a barrel thread, trigger travel limit screw, grunt screws that hold the safety retaining spring in. Use on parts that have alot of vibration.

Use the larger tap sizes for things that can have some play and the screws could have play in them or have another force applied to them to hold them in place. (IE: screws that hold the sticky grips on the intelli frame screw in smooth but dont come out because when tightened up, the grip actually pushes between the head and the frame causing it to stay snug.

I dont know if all thats perfectly true,... but Im using 60% all the way so far at its holding on everything I've milled.

[SR_matt]

i went and looked at my guide and the way it is set out it says the 75 is to be used on very shallow screws buut that it doesnt hold as well (even though the bit size to be used with it is smaller so im nto sure)

either way i dont think im gona be worrying about that for now and ill see what works when i need to start doing stuff alot.

thanks

-matt