Large diameter tap - photo

[Altair]

Large diameter tap.

Fullsize image: https://s3-us-west-1.amazonaws.com/h...p_fullsize.jpg



Previously:

Tapping machine - video
Tap wrench - video
Tapmatic - video
Magnetic tapping fixture - video
2-inch power tapping - GIF

[Frank S]

You can bet he is not taping those holes with that tap but using it to clean up the threads.
We used to have a 50 Hp Cincinnati mill for taping 41/2" holes in 6" thick material. if that thing hung up for some reason the tap would grenade. the shrapnel would dent the 1/8" thick steel safety shroud around it

[Toolmaker51]

Large diameter tap.

Agreed, just chasing the existing threads. No one is pulling such a tap with a peg-legged [one handled] wrench.
More of a wonder is stack of adapters in use; kicking up size of 3/4" drive to socket engaging the tap. I count 3 of them.

[Frank S]

Agreed, just chasing the existing threads. No one is pulling such a tap with a peg-legged [one handled] wrench.
More of a wonder is stack of adapters in use; kicking up size of 3/4" drive to socket engaging the tap. I count 3 of them.

The 12 pt socket to fit the square drive of that tap would have a 1 1/2" sq drive then the 1 1/2"to 1" adapter then a 1" to 3/4" adapter driven by a 3/4" ratchet with a pipe cheater
A tap that size costs upwards of a couple grand even a 3 1/2 12 TPI plug tap will set you back $1300.00. If it were in my shop and I needed to chase some machined threads with a pat that size there would be a homemade tool posting for a proper 6ft long tap handle by the time I got through