[jpatz18]

Im trying to tap using a 1/2 tap. I drill with the 27/64 and as soon as i start the tap it locks. So that means im probably try to tap hardened steel. I cant for the life of me to get it going so i have been tapping using a 15/32 drill. I tap it with success. Is there an easy way to tap hardened steel?

Also im tapping the holes and using a nut threaded on first. Then thread the bolt in the hole as far as it will go and then tightened the nut. I am correct as the nut will take the brute force of the impact correct.

I am not a machinist.

[Delw]

My guess and I am usually 100% correct, is you bought a cheap tap.

[jpatz18]

irwin... What kind do you recommend for hardened steel?

[Dylwad]

irwin... What kind do you recommend for hardened steel?

Any besides Irwin check Mcmaster Carr for good taps, and some info on the different types.

It's probably not hardened steel if you can tap it with a bigger starting hole, I would say the tap is too dull, or it's a bottoming or plug tap, in which case starting with a regular or gun tap would be best, finish up with the bottom or plug tap if it's a blind hole.

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[juergenwt]

If you are tapping 1/2-13 than 27/64 is your tap drill. If you drilled the hole with a HSS drill than you do not have hardened steel. Problem is your tap.

[109jb]

Are you using a bottoming tap?

[neilw20]

Taper or intermediate tap, and use some sort of cutting agent. Don't do it dry.
Sounds like a cheap tap. Does it have nice sharp cutting edges? The the cheap ones have hard burrs on them and they will only cut wood, and make a mess of that.

[Shane1234]

get yourself a nice guhring spiral flute tap !

[fizzissist]

At least there's an admission to not being a machinist... For that, help without the sarcasm is cheerfully granted.

As noted, if it's steel that's truly hardened, you wouldn't be able to drill it with a regular high speed steel (HSS) drill. Since you don't mention which 1/2" thread, we'll assume it's a 1/2-13 (13 is the number of threads/inch,,, and a common one for that diameter), and using the machinist's bible.. Machinery's Handbook (15th Edition, in this case.. ) the hole needs to be .417-.434" dia. In your case you want it to be on the big side.

There are tap guides with spring loaded tips... You should drill the hole (you're using a drill press, right?), and leave the part clamped in place. Put the tap guide in the spindle and use your tap wrench to turn the tap while the tap is being pushed gently into the hole (no, don't turn the spindle on). This will keep the tap aligned nicely and help minimize binding from the tap going in sideways.

Don't use a cheap tap. Get a Guhring, OSG, Emuge, or other quality brand. Be nice to it and it'll last you a long time. I like 3 flute taps, "Plug" for general purposes. Get a can of Moly D or some kind of cutting oil you can dab on with an acid brush.

.... If you had a CNC, it'd look like this...
How to tap stainless steel - YouTube