Warning: Rapid Reversal of scroll chucks can unwind jaws

[troup]

Not sure of the etiquette, as I'm new to this forum, but I just made a disturbing discovery about rapid reversal (or more accurately speaking, de-reversal) of self-centering chucks which I've posted at

http://madmodder.net/index.php?topic=2323.90

I would strongly urge anyone considering the instant reversal possibilities of a VFD / 3 phase motor combo for a lathe to read about what can happen.

At the very least it's not good for the lathe, if the chuck jaws were to self extract at full speed.

At worst it's not good for the operator, or anyone in line with the chuck.

[ieezitin]

This guy brings up a good point.


Since most are well versed in machining, and we assume most know we do not pay too much attention to safety.

Maybe a thread on safety and peoples experiences on running lathes and milling machines would be helpful to people who are just experimenting with there machines.

Ive worked all of above and still get nicked by machinery after 30 years but as I get older it dose not happen twice.


Anthony.

[Yorkshireman]

The very same thing once happened to me on a Myford Super 7.
I changed a chuck, and as a rule I always clean the threads on the headstock, add a drop of oil.
Then I worked on a fitting and later operated the clutch to stop things for a tool-change.
But the chuck did not stop that quickly, unscrewd, jumped from the lathe and then danced through my workshop.
Scary, I can tell you!
Luckily no damage to myself of the Myford.
Johannes

[bry1975]

IMO the smock wrapped around the lathe chuck is one of the scariest lathe accidents I've seen!

Bry

[Bogstandard]

I think we have all had a brown trouser moment sometime in our lives whilst using machine tools, and no matter how much you push the 'nanny' safety precautions things, accidents will still happen (see below).

The biggest safety feature that can be used in a workshop, is COMMON SENSE. If it feels, looks, or even if it just makes you think about it being 'iffy', DON'T DO IT, it is as simple as that.

If you haven't got common sense, then you should be sitting in a rocking chair, knitting a new coat for the dog.

BTW, accidents don't happen, they are all caused.


Bogs

[Mike Cole]

As my first proper post , my two bit about  shop saftey is ALLWAYS wear glasses when using lathe or mill. I have had a trip to the hospital a couple of years ago to remove a spinter of steel from my eye. Not very nice .

Mike

PS sorry no pics this time