how would this be for a spindle motor

[justin_sane420]

i was thinking up a design for my machine (i already have an xy table with no motors, and im building a z axis comumn for it, and i thought up an idea for a spindle motor. i have a mastercraft spinsaw, and i was wondering if it would be sufficient. i know i could use it for engraving but i was wondering how if it would be good enough for milling/drilling/etc for aluminum and in a less likely situation some steels. its rated as 120vac 60 hz, 6 amp, 7/8 hp (but it says maximum developed), and rated for 20 000-30 000 rpm variable speed. i figured if it isnt good enough for milling the stuff i want, i would eventually build a new spindle assembly that has the hp/torque for what i want. one thing i was wondering is that if its rated for such high rpm, what could i do to reduce the speed and increase the torque without overloading the spindle? it says its for running 3/32 to 1/8 shank tools. also what would be a good motor spec for milling steel/stainless if i was to build a new spindle assembly for that? and steppers strong enough for this application (and also for a rotary table)? my table has 8"travel both directions and i was planning on running 8" for the z axis assembly as well. any help would be greatly appreciated. feel free to email me at justin_sane420@hotmail.com if you have any advice/suggestions.

[ViperTX]

It would be good for light milling of wood, plastics and aluminum. I suspect that the bearings are not made for any heavy duty work....steel is out unless you want to crawl.

[justin_sane420]

perfect thanks. just for future reference does anyone know specs of a motor that would be alright for steel? i think im going to try (sometime somewhere in the future) to build a machine for steel, but i dont think the platform i currently have would be rigid enough for it. id have to either A) make really small parts really slowly, or B) build a completely different machine. but i think id go for B because im only really interested in plastics and aluminum for the time being. also what steppers would be good for the aluminum? (i dont want to spend more than i have to for this machine, and then when i build the steel cutter ill actually drop the real cash that is necessary). also for the steppers for steel what would be ok for that?

[ViperTX]

Well the construction of the spindle is of upmost importance when machining hard substances or substances that are hard to machine. JRogue has a nice thread of a spindle that he built and it's powered by a motor from a treadmill walker...he's had some problems with the motor at high RPMs 8,000 and was looking for another motor....any of the variable speed DC motors in the 1HP and up range that are built for industrial use (TEFC) should work...just depends on how much you want to spend. You could also opt for some of the AC motors (3phase) that you could use a VFD on.

Primarily think about the quality of the spindle and its bearings.