Thread tapping

[God mode restorations]

Evening chaps.
Quick question. I am tapping some m16 threads in to a blind hole. Now the taps I have are designed to basically run right through an open hole. Will a bottoming tap cut to the bottom of a blind hole. I have threaded as far as I can go with my taps but am missing a few cuts at the bottom .

 

[MBB]

That's normal.

 

[God mode restorations]

That's normal.

Yes. But I kind of screwed up. As my threaded rod needs to bottom out but it cant

 

[God mode restorations]

Think I Sussex it. My taps are tapers. I need to finish off with a bottoming tap .

 

[frank horton]

even with a proper bottom tap there's usually 1/2 a thread u never get..........if I need the stud to directly bottom out to the plate below I turn of the last thread on the stud...........
or u can grind the tap dead flat on the bottom but the last tooth will be very fragile......!!!!!!!!

 

[eLuSiVeMiTe]

What frank said. Bevel the bottom of the rod to allow it to contact the bottom.

 

[Rocketman]

As elusivemite says relieve the bottom of the rod. Really to do it properly use a slot drill to get a flat bottom in the hole and then tap with the first/second tap and then finish with a plug tap

 

[johnik]

weld a plate over the bottom of the hole or if you need it flat, cut a section off the stud, screw and weld that in the bottom of da hole

 

[God mode restorations]

Sorted the problem. Altered my drill bit so it will cut the bottom of the hole flat. Just got to remember to buy two drill bits of the same size when I need different sizes .one to cut the hole. And two to cut the bottom . Got new taps on order. Happy days.