"Harold and Susan Vordos" wrote in message
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"Ignoramus14555" wrote in message
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I think that I have the same chuck on my clausing lathe, four jaws and
foud adjustment points. Very strange. Why would they even want to make
them like that.

Could be that in wood working it makes little sense, but when machining
metals, it makes all the sense in the world. A 4 jaw chuck is the most
precise of all holding devices *because* it allows for independent
adjustment. The level of precision is up to the operator, unlike the
typical universal chuck (typically a scroll type device that adjusts all
jaws simultaneously). With such a chuck, you're at the mercy of the
level
of precision inherent in its manufacture, plus the results of use and
abuse.
Because all the jaws work together, you can't make adjustments when
they're
off, although there are three jaw and six jaw chucks on the market with an
adjustable body. If one had but one choice for a lathe, it would
have
to be an independent 4 jaw, otherwise many jobs would be impossible to
hold.
They are often slower, but very flexible.

Don't overlook the fact that irregular items can be held as well, and parts
can be held such that diameters can be turned eccentric with one another.
Very important if you're trying to build a crank shaft or eccentric device.

Harold