So I’m looking at designing the spindle for my machine but I’m not sure of the best way to go.

Ideally I need it to able to machine wood and metal so high speed and high load will be needed. I have considered just fitting an interchangeable plate on the z axis to fit a router when needed but I would rather use a 3 phase motor and VFD so I can control the RPM, which means a separate spindle is required.

I bought the Spindle book from the Workshop series which covers small tool post grinders for Lathes. For the spindles in the book it says that ‘any’ type of bearing is suitable, even deep groove ones, but for higher loads then use Tapered rollers B’s ( I presume because of the relatively low grinding and milling speed required by a lathe). However after looking at the data from the Bearing manufactures and other peoples spindles then they use Angular contact bearings for the high speed designs.

The biggest problem I seem to be facing is that spindle design is basically a compromise to make it fit for purpose, if space is limited and the tool holder is big then it will require a different layout to say a integral motor design so I’m not keen to just copy a design without understanding why.
At the moment I’m only looking at what bearings to use and the mounting arrangement so the basic design parameters are

1. High load (milling)
2. High speed (routing)
3. ER 32 collet holder
4. Belt driven or end mounted motor

So has anybody made something like this or used normal bearings in a spindle?

Im initially looking an somting like the ones below from SKF web site, but I might be aiming a bit high

http://www.skf.com/portal/skf/home/p...newlink=9_10_8