CT40 vs. BT40 spindle's and tooling?

[gunsmither]

Total newbie question here.

I'm about to purchase a Haas TM-1, and I'd like to know the difference between the CT40 and BT40 spindle's, and availability, and or desireability of tooling for them.

In other words, which one should I get?

Any help, or links, or suggestions, etc. will be most appreciated. Thanks! Joe

[steveg]

The differance between CT and BT is in the tool changer flange,
and inch(CT) ,verses Metric(BT) threads for the pullstud/retention
knob.
CT is the american standard (first clue ) and BT is the Japanese
standard. there is also a euro standard ,ISO

As you live in the US CT is the way to go, every tool company
will have CT wereas BT is often special order, and no doubt more expensive.

The spindle of the machine as actually identical regardless
of the Tool holder, CT,BT or ISO, what is differant is the tool change
arm or carousel grippers (dependent on model).

Functionally there is absolutely no advantage or disadvantage
of any of the 3, just the ease of purchasing, and for you CT wins
by miles.

[gunsmither]

Thanks very much steveg for the excellent explanation! Joe