[bengineer]

Hi,

I'm not sure if this is a proper place for this post, but I couldn't find a better location.

I'm wanting to design a spindle cartridge with an automatic drawbar somewhere in the 1-3 Hp range / maybe 4k to 6k max rpm.

It seems that by far the largest problem I'm looking at is locating a frameless motor (or I'd settle for a very large hollow shaft - somewhere around 1.5-2" bore) that's large enough and that I can actually purchase (not being an OEM).

I've searched the web for months now. Ebay is an option, but I'd like to have the ability to purchase an exact replacement if it ever goes bad.

Does anyone know of a seller/reseller that sells large frameless motors to individuals?

Thanks!

[Jawno]

I'm pretty clueless about how an automatic drawbar works and don't know of a source for frameless motors either but kind of wanted to say that if your having a big problem locating a component like that, that seems pretty central to the design, maybe you need to change the design. Don't most automatic drawbars just use a belt and pulley on a traditional motor? I think thats the way our Bridgeport is set up but like I said I'm kinda clueless there. Hope you don't find this post offensive. Just wanted to help.

[Al_The_Man]

I know Aerotech make them, there are also a few other manuf.
S Series Frameless Torque Rotary Motors
Al.

[bengineer]

No offense taken, I'm sure many who view this post probably think the same thing.

I'm currently building a 3-Axis gantry mill with a belt and pulley like the Bridgeport. But the more effort I put into it, the more I want out of it. So I'm planning to finish this machine in order to help make parts for a second, larger & more capable machine. I'm hoping the second machine can have tilt head (maybe even a tilt/rotary head) and in order to keep the spindle from getting too bulky I can't think of a better way than to use a hollow shaft / frameless motor inline with the spindle shaft, rather than an offset motor pulleyed to the spindle shaft.
If I can't find a motor, then no huge deal, i suppose. I just won't have a tilt head

[mike_Kilroy]

http://www.kollmorgen.com/en-us/prod.../direct-drive/

[RICHARD ZASTROW]

There are a few motor manufacturers that produce the hollow motors. As mike kilroy stated above, Kollmorgen has about the widest selection. Bosch/Rexroth, INA, Yaskawa and Etel all produce them as well.

I've designed Kollmorgen KBM's into one machine and Kollmorgan DDR's into a second machine so far this year.

Last year we did one with the Etel hollow spindle motor.

All have worked fine.

Dick Z