I had an inquiry about how the Taig Spindle could be taken apart and the cartridge used elsewhere. I had to be honest and admit I had never taken one apart to investigate. Taig products are so well built there was never a need to disassemble the spindle.
The new spindles are different than the older versions. The new ones have the cartridge insert from the end. It slides into a machined bore. The old heads have a split case. The pictures here are the old head. Both hold the cartridge in place with a recessed screw into the center portion of the cartridge.
I wasn’t and still not interested in pushing apart one of my ER spindles to view the cartridge. There may be no harm, but if it isn’t broke now, why look for a problem? The old split case is no problem. The side will almost fall off when the bolts are loose. Probably the reason for the change to the new style.
At first look it appears to be four bearings. The center section is not bearings (as far as I can tell). The end bearings are compressed against the center core providing proper bearing pre-load. The pre-load nuts are on the outside against the bearing case. The center section is under compression.
To me it looks like a very elegant design and has been trouble free. First class machining, not like the cheap imports. It HAS to be to run at 10,000 rpm. That doesn’t imply all imports are cheap but few are rated for that kind of speed.
So I suppose you could make your own spindle case if required. I run the spindle at 10,000+ rpm all day with no heat buildup (after initial break-in). Perhaps the cartridge could be pushed faster with bearing cooling. However, for the novice there are other requirements like dynamic balance. There is a lot of mass there.
I read the “speeder” 30,000 rpm spindle adapter on the Tormach machine is really rated to 20,000 rpm. Even then, they have had to resort to dynamically balanced ER16 collet nuts to run at that speed. Experimenters beware.