Im trying to build my own Mini i have access to a full cnc shop but my main problem is find a spindle moter also im not sure on what hp i need to do some medium cutting on alum.

If aluminum is your main intended material, you will benefit from a fast spindle. XX,000 RPMs would be nice, but are really not very realistic for a DIY machine unless you are prepared to spend a LOT of money to do things right. Tool and toolholder balancing becomes a very big issue once you pass about 5000 RPM.

What size of machine are you looking to build (estimated cutting area, X, Y, and Z)? Perhaps a 1/2" router may work for you... Perhaps you could get away with a Taig or Sherline spindle. It all depends on what you want to do with the machine. Give us some more details on what you would like to do with it and we can give you more guidance on spindles and motor HP.

Ithink that i have most of the mechanics figured out i plan to use topball slides from nippon to support and have the spindle figured out useing a 30 taper > The planed size is 34x14x8 thats what im hoping for any way. i plan on building the spindle and i thouhgt about building the moter as well ,but i couldnt find any formulas to translate power and speed

the yahoo gingery group
If you've got access to a full machine shop this should be pretty easy for you. You should be able to cnc the parts that are hard for most home builders on their mill rather than cast it etc or buy it. (The x,y table and the head are the expensive parts along with the speed controller)

Using pulleys to control speed you can set it up without even that and add it on later for better control.

Id really suggest what they said up above about the spindle. Its the most important thing on your machine. You can fudge to fix inaccuracies in your machine on the parts and get them right. You cant fudge a spindle turning 5000 rpm's blowing up

The great thing about diy is you'll be able to set it up from the start with an easy to change head and motor setup. so you can slip in a 1hp,2hp.. whatever size motor you want.

I envy your machine shop access.

Originally posted by lancedulak
the yahoo gingery group


Could you please give a full url for this group ( if my understanding are rigth ) ?

Thanks
Pigi

You might want to look at Swede's mill here http://www.5bears.com/cnc.htm

This site rocks....

Thank you very much

Pigi