First off - sorry if this is in the wrong forum! I don't post very often.
To business: Just as a hobby endeavour, I'm going to design a medium size spindle for an imagined (later to be designed) 5 axis gantry-type machine. I have a few goals: design a spindle which is as mechanically sound as possible (so that, if one were to build it, it would work) and a spindle that I actually like. There are a couple of things I'm aiming to do, right off the bat: first, I want to use a frameless BLDC motor mounted on the spindle as the drive. Something like Parker's SKW073_XXXLAM (pdf link) motors - these are relatively high-power but small (the smallest motor produces 3.1 kW of output power in a package 80mm in diameter and 114mm long!). I like the concept of the spindle being an all-in-one unit, with only one moving part: the spindle itself.
I'm aiming for a BT30/ISO30 taper. I'd also like to do a power drawbar so that the spindle is ATC-ready. I've read other people having trouble with power drawbars pushing the toolholder offcenter due to the balls in the gripper not properly centering, to avoid this I'm thinking a floating gripper is the best bet - where the gripper is secured to the drawbar by something like this, so it can pivot. My starting question is: does anyone know where I can find the specification for the BT30 taper? As a follow-on, is there a certain kind/shape of pullstud I should design the gripper for?
This design is currently only a sketch on engineering paper, but I'd like to go all the way through CAD drawings as an exercise, and actually do the calculations on estimated cutting forces and deflections. If somebody can tell me where to find the taper specification, I can start drawing something for real. As a side note - is a labyrinth seal the only good way to keep chips/coolant/etc out of the lower bearings?
Ideally this is a solid design that I can sit on until I have the financial resources to actually build one, so I'm aiming for the best spindle I can design.