KDN high speed spindle, was Re: milling circuit boards

This high speed spindle appears to be a Proxxon hand grinder attached
to a bracket.
There will be a huge difference between a machine tool spindle and a
hand grinder. For example, the hand grinder has no need of axial
stiffness or dimensional accuracy. Runout is also not very
important, to a few mil level. Since this grinder appears to be made
mostly of plastic, there will also be thermal expansion issues.

No doubt it will remove material, but don't be surprised if it is the
limiting factor in the precision and smoothness of cut of your mill.

regards-
Elliot

>
> Here is my previous write up.
> Looking for an affordable high speed spindle for your SIEG X1, X2,
> or X3 - or for any bench milling machine? I've been looking for one
> for over a year, and finally found one at KDN Tool.
>
> I first looked at the NSK Astro-E 250, which sells for over $2,000.
> I can buy 18 of the KDN Tool high speed spindles for the price of
> one NSK Astro-E 250. The solutions I found on ebay, the internet,
> and in the discussions on Yahoo CAD-CAM-EDM-DRO group, DIY-CNC
> group, hf47158toCNC group, Irk-torquemax group, X-Series-Mills
> group, and CNCzone came close, but not quite close enough in price,
> power, number of collet sizes, reliable collet chuck design for
> small end mill shanks, air cooling, variable spindle speed,
> commercial designed spindle nose bearings, low spindle run out,
> quiet running, and a fairly good duty cycle for long jobs.
>
> I've got it on order - 5,000 to 20,000 rpm with six collets 1/32"

to

> 1/8" - for $170, which includes the mounting bracket for the SIEG
> X2. You will find it on www.kdntool.com
>
> Finding the KDN Tool spindle has been quite an adventure. When I
> first got into CNC, I determined that I would not be primarily
> making conventional machine parts, but would be engraving, and
> sculpting plastic, aluminum, and brass. I was surprised to learn
> that I would need a high speed spindle, for the same reason that

PWB

> drilling, and engraving applications demand. The very small

diameter

> end mills require the high speed. My stock SIEG X2 at 2,500 rpm
> needed to be stretched up to 20,000 rpm. No way. I looked at high
> speed routers (collet limited to one size), air driven spindle
> motors (too noisy), hand pieces for manual grinding, engraving,
> sculpting (not enough power or too expensive), and die grinders

(one

> speed).
>
> Th