In article , Rex B "" wrote:
I've uploaded to the dropbox a photo of an item I qcquired last weekend.

http://www.metalworking.com/dropbox/Indexer-1.jpg

Do you have any other views of it? In particular, a view square
on to the end of the shaft with the crank would show whether or not it
has the indexing arms designed to mark off a sector so you can advance
to the next cut without having to count holes each time. (Those make it
a lot easier to use for cutting gears and the like.)

Also, another view -- perhaps from the other side from the first
I requested -- might show whether it can be tilted at angles other han
parallel to the bed.

Note that the spindle is both equipped with a socket for a
standard taper (usually B&S taper for indexing heads, though this one
might be a Morse taper -- or something else entirely), and a thread for
screwing a chuck or a faceplate onto it.

The first thing to do is to make a mark on the spindle (layout
dye would probably do well, so you could scribe an index line without
damaging the metal of the spindle), and see how many turns of the crank
are needed to bring the spindle one full turn. The most common one is
40:1 ratio, though there are 60:1 and 20:1 as well.

It's either a dividing head or a rotary indexer. It only has the one
plate, and the numbers on it seem odd, something like "3 7 13 17 23 etc"

That is only one of (typically three) plates. And I am
surprised to find 3, as that is often subsumed in a 12 or a 33 ring.
The other two plates cover some of the gaps between the existing rings,
and these all have to take into account the spindle gearing ratio.

What is it properly called - rotary indexer, dividing head?

Both should do.

Does anyone recognize it by brand?

Not I.

Are additional plates available?

It depends on who made it -- but it can be used to generate the
other plates with a bit of work. (If the head does not swivel to point
up, you will need to mount it on a right-angle plate on the mill to do
this. And it might be easier to use with a 3-jaw chuck mounted on it
with reversed jaws to grip the other plates.

How is it used, what is it good for?

Some of that is covered above. But its basic purpose is to
divide a circle into a known number of increments. This can be used for
such things as cutting gear teeth, making new index plates for it,
spacing holes around an object -- such as holes for mounting a backplate
to a lathe chuck, or drilling evenly spaced holes for a tommy bar use to
screw an adaptor onto a spindle, or to remove it.

It could even be used for decorative milling to produce
something other than standard knurling on a knob -- perhaps making a
fluted knob.

Do I need to keep it or sell it? I have a 9" logan lathe, shopping for
a mill.

You will find uses for it with a mill. You can even find uses
for it on a drill press, as I have.

Ideally, it should come with a center tailstock holding a center
at the same height above the table as the one in the head, and with an
adjustment to extend or retract the center. You can make this if you
must. Otherwise, you will be limited to workpieces which can be held in
a chuck threaded onto the spindle.

Value? Unless I can be convinced I need it, it may be available for offers.

If it does not have provisions for setting the spindle to other
angles relative to the table, it is less than with one which has that
capability. Mine does have it. This one appears not to have it.

Look on eBay for a while to try to find one close to that.
Consider what it may cost to get one to replace it when you discover
that you do have a use for it. I kept hold of mine some twenty+ years
before I got a mill (though I used it on a drill press from time to time
in the intervening years).

I would keep it -- but you may not wish to.

Good Luck,
DoN.
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