CAT40 Big PLus

We are purchasing a new Okuma Genos M560 with the CAT40 Big Plus spindle. This is our first machining center as we have a number of Prototrak Bed Mills and lathes and are in the process of researching tooling holders and fixturing. There are allot of threads about Tool holders but most are dated at least a few years. Any input on brands of tool holders or fixturing would be much appreciated. We are a machine builder so we make everything from small plates with clearance holes to large $250k pieces of tooling. Thanks for the input.

I've used Nikken exclusively for years. End mill holders, collet chucks, tap holders, collets and have had very few problems. Not sure if they make Big Plus compatible tooling. As I understand it, the only time Big Plus is an advantage is deep cut side milling, so would you need it for drilling and tapping?

We buy from Mari-Tool.
Excellent quality and prices.
CAT4 Dual Contact Tool Holders made in USA - MariTool

Is Big plus the holder and spindle both? I understand the concept, but I have never used or seen any of it. So is the spindle face a smidge lower than normal, and the holder a smidge higher so they contact...?

I think the nominal spindle dimensions are the same- Frank may correct me on this...

The Big Plus spindle has a ground face and the distance from the gage line to the spindle nose is held to tight tolerance.

On the holders, the flange is thicker on the Big Plus to take up the ~1/8" gap that you see in a standard CAT40. They look kind of like a cross between a BT and a standard CAT.

You can use standard CAT holders in Big Plus spindles, but the MTB's usually say don't mix-and-match, because there is a risk that a chip can get between the holder and the spindle nose with a standard CAT. Then you do a tool change and the chip can get squashed between the spindle nose and the Big Plus holder.

If you are tooling up from scratch, just buy dual contact everything. I use Techniks and Parlec holders and I like them, but I am planning on ordering a couple ER11 collet chucks from Maritool.

Mentioned above, you don't need the rigidity of the dual contact for most drilling and tapping operations- but if you have a high speed spindle, the dual contact will prevent the tool creeping up in the taper when the spindle is hot. A standard CAT40 holder can move a little as the spindle expands.

The gap between the spindle face and the tool holder flange face on a normal 40 taper spindle is .125" or more. With a dual contact spindle the face of the spindle is .04 longer and the tool holder flange is .085" thicker. With this setup you will not have any 40 taper tool holder ( dual contact or standard) will fit in any spindle ( dual contact or standard). Just if you buy and use a dual contact tool holder in a standard spindle ( such as a HAAS spindle) you will not have any flange contact and you are just wasting your money. Tool holder will not interfere with spindle or the ATC.

With dual contact you dont have the problem of a tool getting sucked in too deep by a warm spindle. No more tools sticking during a tool change.