Flexshaft overheating suddenly

I just got back into my studio after spending months primarily in the local
arts center studio. Went to clean a piece and the flexshaft handle got
incredibly hot very fast and stayed that way. Does anybody have any advice
as to why that would happen? I am going to relubricate the cable today but
I doubt that is the cause as I am pretty good about doing that. I don’t
want to burn out the motor, etc. so I will await your valued suggestions.
Thank you all so much. I feel so fortunate to have such a wealth of
resources available through Orchid! SHael dakotahdog@msn.com


My Foredom and #30 handpiece overheated from too much oil in the cable and
handpiece. If you lubricated yours and left it a while, maybe the oil
just drifted down the cable and caused problems.


The handpiece was just dirty. Not from misuse but it sat idle for a
couple of months in which time the old oil and grease had a chance to
harden. Clean the flex shaft and re-lubricate with lithium or moly grease.
It might be worthwhile to disassemble the handpiece itself and use “Break
Free” or some other PTFE containing lube and clean and lube the handpiece.
If the handpiece is not “disassemble-able” check with the manufacturer and
see what they have to say. Mike

Went to clean a piece and the flexshaft handle got incredibly hot very
fast and stayed that way. 

G’day; I suggest you remove the handpiece from the shaft, and the flex
shaft from the outer flex tube, and soak the lot in kerosene and wash it
well; use an old paint brush. Dry it all out as best you can with tissues
of rags, allow it to drain thoroughly - overnight preferably - then
relubricate the lot with fresh low viscosity MINERAL oil. (Vegetable oils
oxidise and goo up - and I have me doubts about three-in-one too!) She’ll
run like a box of fluffy birds! And cheers!

        /\      John Burgess
       / /
      / /      Johnb@ts.co.nz    
     / /__|\

Shael - It sounds like the bearings in your hand piece may be worn out.
Friction between parts is most likely causing the heat. It is unlikely
that heat is transferring from the shaft. Check with the manufacturer, or
the paperwork that came with your machine to see if it is possible to
lubricate the hand piece or if it is one that has a sealed bearing. If it
is a Foredom machine, you can send it back to Foredom and they may be able
to recondition it. Otherwise you will probably have to buy a new hand
piece. Steve.

Steven Brixner - Jewelry Designer - San Diego CA USA

Clean the flex shaft and re-lubricate with lithium or moly grease. 

Where does one get this stuff? Thanks in advance!

Lithium grease can be found at most gun shops. It is known as M1 grease.
Used on the M1 Garand Rifle. Generally it is white/Yellowish in color and
is in small yellow capped tube-letts designed to fit in the butt stock of
the Garand. Molybdenum (spelling?) can be found in any machinist supply


Hi Fshbreath,

Try the hardware store. Most well stocked stores will have one or both in
small tubes (about 5 inch long). Incidently, the moly sands for molybdenum
(sp?). If the hardware store doesn’t have it, try an industrial supply
house. If you want to get larger sizes, 5 gal. or larger, check the yellow
pages for oil companies. They usually stock many different lubricants most
folks never dreamed existed.


I replaced the bearings in my Foredom handpiece with ABEC-3 rollerblade
bearings - same size, and although it still heats up a little, is much
better than the old, destroyed bearings that were in it (used for lapidary
work). This is a cheap option.You can even get ABEC (tolerance/precision
grading used by bearing mfg.) of higher numbers. The size is the same, and
the id numbers on the bearings are the same as one of the bearings in the
old unit. Unscrew the back of the housing, and the whole assembly will
probably come out. Then unscrew the preload nut, and press the bearings off
with an arbor press. press on the new bearings, reassemble.

flexshaft overheating cause possibility: … after moving my flexshaft
hanger thingy over a little to accommodate another piece of equipment, i
found the handpiece heating up because of the more acute angle of the
flexible cable conduit. good luck - ive