Re: High Speed Spindle for SIEG X2 - Finally .... ... just a nagging doubt ?

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Chris Horne" <chris@...>
wrote:

>
> A bit of a question regarding these proxxons
>
> I like the Proxxon tools a lot for hand use and this new one looks
> just the biz.. but..
>
> The literature says 'rated for 30 minutes continuous'
>
> I don't want to spoil the party, but
>
> Has anyone used them as a mill spindle for an extended period of

time?

>
> My application is 15 minutes on, 30 seconds off all day long.. is

it

> going to go bye byes in short order ?
>
> and if it is the bearings that fail.. can they be changed

relatively

> easily?
>
> Chris

Chris,

I bought a Proxxon hand held, flexible cable spindle (Flexishaft, I
think it was called) to use with my little cnc router. While I was
in the store, I looked over and compared the regular hand held
grinder spindle with the flexible cable one and they looked to be
identical with the bearings set up the same on each. I intended to
use the flexible cable spindle with a lower speed, much quieter
motor and belt system to provide 25,000 RPM to the spindle. I ran
the flexible cable spindle for about an hour or so at that speed,
cutting out a pattern, before I noticed the plastic coating around
the "speedometer" cable was melted in the middle of a wide sweeping
turn it made! It only had that large radius 90 degree turn, but
obviously it couldn't take such continuous duty operation like that.
I cut off the flexible cable and mounted an old Dremel type grinder
motor, that I had modified to run full speed continuously, behind
the Proxxon spindle to drive it. That system has run overnight lots
of times and not developed any problems. I've felt the bearings of
the Proxxon spindle while it was running, and they barely get warm
to the touch after several hours. My housing, though, does provide a
heat sink of sorts.

So I think the spindle bearings will not be the weak point. I don't
have any idea what the grinder motor will do, though. The bearings
don't seem to be too bad to remove and replace, if that would become
necessary. They are held in place by a small snap ring on the
spindle.

Irby