I fixed the Dumore flex shaft grinder yesterday...

the square keyed end of the flex shaft had broken off ahead of the
flex itself, leaving a small swaged feature, with the wire sticking
out of the end of it.

So I used the TIG, and melted the end of the wire into a mass, then
chucked the swaged end in a collet, and cleaned it up, then bored a
very small counterbore about .250 x .020 deep.

I then made a matching end piece, with a square key, by turning it on
the lathe, then chucking it in a spin indexer and milling the square
key, then reversing it after parting it off to length, and machining a
boss to fit the counterbore in the swaged piece (to keep concencitity)

Then clamped them together in a vise, and using a .040 electrode,
tig'd them together. Putting the welded assembly in the collet, I
cleaned everything up in the lathe, then put it back together.

It runs fine.

I think however..I made a mistake..I filled the flex shaft with
grease, and stuck in the flex wire..now it runs hot. The handpiece
runs very hot, even though the bearings appear to be free and spin
easily. I filled the handpiece with ATF over night, and will see if it
still runs hot here in a little bit.

Any hints on care and feeding of a flex shaft and hand piece?

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner