On Mon, 3 Aug 2009 19:07:47 -0700 (PDT), N Morrison
wrote:

On Aug 2, 5:59*pm, "Michael Koblic" wrote:

Questions:

1) Is such degree of heating abnormal?

Sadly no.

2) What is the likely cause? My first thoughts was "bearings" but why would
the housing be hotter than the shaft? Superficially there is nothing to
suggest that the bearings are at fault.

It's the motor design. Cheap to make, not so good to run. People have
had much better results with a 24 VDC electric scooter motor, about
150 W. You can machine steel for 30 minutes and the motor barely warms
up, plus you get excellent speed control. They are being surplused
right now.
My little DP came with a 1/6 HP motor that would get too hot to touch
almost before you turned it on. Now it has a 1/3 HP I bought three for
a dollar and I can work all day and still grab it.
Gerry :-)}
London, Canada