Re: [CAD_CAM_EDM_DRO] What's the difference between a dividing index and a rotary table?

Lloyd Leung wrote:

> Please excuse the newbie question.
>
>
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> What's the difference between a dividing index and a rotary table?
> Besides in price?

Most literally, a rotary table is just a table, with no through hole. You
could mount a chuck onto a rotary table with a suitable adaptor.
Many rotary tables are not designed to be turned while milling, and
when you loosen the locks, the table may lift off the base somewhat
under side loads.

A dividing head pretty much always has a through hole, and usually
is designed to have a jawed chuck or collet hold the part.

The dividing head may be designed to hold the part under cutting loads
while being turned (good for making helical gears). the bearings
on a dividing head are more like lathe spindle bearings than on the
rotary table.

Finally, the dividing head is usually equipped with plates with rings
of holes for dividing the rotation of its main spindle into a very great
variety of possible divisions. They have two arms that help you make
the correct partial turns without counting holes each time.

> Is one more heavy duty than another?

That is not really the difference, it is the purpose for which they are
designed. If you want to drill bolt hole circles in a flat plate, you used
to use a rotary table, before CNC, Now, the CNC system can put the
holes mathematically where they should be, and the rotary table is
nearly obsolete. (There are tricky ways to use them to expand the
reach of a machine, and they can be mounted on their side to get
4- and 5-axis capability.)

The dividing head is used for cutting gears, sprockets, escapements
and all manner of symmetrical mechanisms like that.

Jon