Low speed mild steel spindle needed

[gtrdude]

Hi, I am building a 3 axis cnc mill around a 150x400mm compound table. I would like to at least be able to mill mild steel without too much trouble. The frame is being made from tubular steel with reinforced diagonals and 1/2" plate steel welded into the open areas. I am finishing work on the z axis now and am researching a spindle. I have been searching for quite a few hours now and can't really find much info on either a.) Low cost off the shelf milling spindles b.) diy spindles. There seems to be lots of talk about people wanting to build high speed stuff but my requirements are a lot simpler than that.

At a guess I think I will be wanting the spindle to handle about 1HP input. It would need to be capable of doing up to 1500-2000 rpm. Speed is not a huge factor as I will only be doing odd jobs on this machine. I'm really more concerned about rigidity. I would like to achieve a 0.001" accuracy if possible.

Can somebody suggest any economical off the shelf solutions? Should I look into diy for this one? I have access to a good lathe. Where do I start?

[307startup]

www.littlemachineshop.com

look for their replacement spindles & headstocks as these will be your inexpensive off-the-shelf option

[RICHARD ZASTROW]

gtrdude, Economical is relative. I don't know if these make it into your definition, but you may be interested. www.rtgilman.com

[JMcDonald]

I made my own spindle using two VXB flanged bearings, a simple HF drill chuck, and a VXB thrust bearing. Each flanged bearing was $10, the drill chuck was $6, the thrust bearing was like $3, and the through-bolt was $2. So about $40-$50 total, after shipping. It feels way more solid than ether of my drill press spindles. Ill post pics and details of it soon.

[gtrdude]

Since I haven't actually finished the machine, do you still have photos of your diy spindle? Boy a lot of stuff can happen in the space of a year or so.

Paul

[JMcDonald]

I don't have it anymore, but here is a diagram showing a little how it ended up. If I were doing it over again I would have put more thrust bearings so I could really crank down on the bolt torque without stressing the axial bearings.
http://www.lindenwoodracing.com/mill_spindle.jpg

[gtrdude]

That's pretty cool man. I'll have to sit down and have a more detailed look at it when I've got more time. Thanks a lot!

Paul