Single point thread tools

[m_c]

Still not sure whether a single-point tool could be used for thread milling (although I don't see why not) even if it wouldn't have the "full hole-depth thread in one rotation" capability of the "proper" cutters as used for production.

They're used all the time. No different from any other milling cutter, as it's rare more than one cutting edge is in contact anyway. The main drawback (or could be classed as advantage depending on how you want to look at it), is a lower feed rate as you only have one tooth doing the work. If you have the horsepower available along with the rigidity to handle it, a multi-thread/tooth thread mill is far quicker, as you can do the whole thread height in a single circular pass.
Off course, tapping is usually quickest, but then you're into needing enough torque to handle the tap, having the capability to handle the required synchronisation, and a tap being available in the correct size.

[magicniner]

If you have the horsepower available along with the rigidity to handle it, a multi-thread/tooth thread mill is far quicker,

That way you will also need the budget to buy a cutter for each pitch you wish to cut.
I have cutters capable of full thread depth in a single pass for frequent jobs but a single point cutter can give you a lot of flexibility for one-off jobs and you don't end up with a drawer full of "once-used" threadmills.

[Neale]

Something to put on the shopping list - slightly further down than the CNC vertical mill conversion...

[Lloyd Barnes]

The reasoning is I have 4 nuts to make. 75mm diameter thread, can you imagine the cost of a 75mm diameter tap!! I would use it twice and in fact need 2 (2 nuts LH thread, 2 RH).

Single point threading seems a very sensible option as I'll be able to use it again for other large but different threads. I'd only need to buy a LH and a RH insert. That's assumes I can find one of course!

[Neale]

Do you need two different inserts? Surely the only difference between cutting LH and RH threads is the movement in the Z axis?

[magicniner]

Do you need two different inserts? Surely the only difference between cutting LH and RH threads is the movement in the Z axis?

That's correct, thread milling tools cut left or right handed threads.

[Lloyd Barnes]

That was my logic too but the inserts still seem to be available in left or right handed versions which makes no sense to me.

I need to spend some time browsing the links provided earlier in this thread at the weekend.