On Sat, 18 Oct 2003 10:01:37 -0700, Brad Brigade wrote:
On Fri, 17 Oct 2003 15:50:37 GMT, (Gary Coffman)
wrote:

Not new price, but perhaps you could find used equipment for that
amount. What you really want for gear cutting is a horizontal universal
mill with a gear driven index head. That'll let you cut helical gears as
well as straight spur gears. Used horizontal mills are often pretty cheap
because most hobbyists want "something like a Bridgeport", even
though a vertical mill often isn't the best choice.

Gary

Horizontal?? Now thats something I never thought of. I've yet to
come across a horizontal mill in all my searching.

They're out there, particularly in industry where their features
make them very desirable. They're rarer among hobbyists, but
several people in this group have them. The universal style is
particularly appealing because the table swivels. This lets you
cut long tapers, something more difficult to do with a Bridgeport
style vertical machine.

If I got a horizontal mill for gear making, would it be any more
annoying to use it for general milling as opposed to a vertical mill?

About the only thing that's more annoying with the horizontal is
trying to use it as a drill press. You'd have to mount the work on
an angle plate and use the table Y advance to drill the hole.

But otherwise, the horizontal works great once you get used to
the idea that the spindle is horizontal and fixed. Even pocketing
work is easier with the horizontal, since the chips tend to naturally
fall out by gravity instead of being recut over and over as they are
in a vertical machine.

Of course a horizontal mill can use end milling cutters mounted
directly in the spindle, or conventional milling cutters mounted on
an arbor. And when you use the arbor and overarm, the horizontal
is much more rigid for its size, letting you take much heavier
roughing cuts, and also letting you gang mill multiple features
in one pass.

And if the index head could stand vertical, then would a horizontal
mill be unneccessary?

Not if you want to be able to cut anything other than a straight spur
gear. Only the horizontal machines have a drive for the index head
that's geared to the table advance, so you can mill a precise helix.

You're pretty much limited to cutting straight spur gears with a
vertical machine. (A CNC machining center could be programmed
to do other than straight gear teeth, but I'm talking about manual
machines.)

The majority of power transmission gearing uses hypoid helical gears,
so you really want to be able to cut those if you want to make gears
on the mill. (There are other ways to make gears, using a gear hobbing
machine, for example.)

Gary