Re: [CAD_CAM_EDM_DRO] CNC Benifits and Drawbacks

Stephen Goldsmith wrote:

> Hello Folks,
>
> This might sound like a dumb question but for the benefit of us newbies
> .....
>
> What are the +'s and -'s af cnc control in the home workshop with
> regards to lathes as well as millers?

It depends on what you are doing. Obviously, when doing many of the
same part, the CNC is a big benefit. There is probably more benefit on
the mill than the lathe, as the turned parts that are usually needed are
simpler than some milled parts. That is a big generalization, of course.

With the milling machine, whenever you need to do something circular,
like a 3" round hole in a panel, or rounded corners in a pocket, etc.
you need to use a rotary table. When you have CNC, a rounded corner
is as easy as a straight line. Also, any angle of straight line can be
handled
without moving the workpiece. this is hard to do without CNC.

On the lathe, so many parts are cylindrical in design, that you can do these

quite easily on the lathe. For turning balls, however, you need a special
attachment, or a lot of fudging. If you make a ball-ended handle just for
appearance, it doesn't matter, but if you want to make a ball on the end of
a shaft for an instrument mount, for instance, then it needs to be pretty
round. CNC can do that. Also, taper turning is a pretty intricate
business,
even with a taper turning attachment. With CNC, you can cut a taper as
easily as a cylinder.

I have retrofitted my mill with a 3-axis CNC, and immediately started doing
things that I couldn't have done easily before without it. I made a bunch
of covers for an instrument that had a round OD, and a large round hole in
the center. I stacked 6 .062" chunks cut out of aluminum sheet on the
bandsaw. I then centerdrilled and then drilled all the holes in the pieces
while clamped to a fixture. I then cleaned out several of these holes and
ran bolts through them into the fixture, and removed the clamps. Now, I
mounted an end mill and cut the OD and ID. When done, these pieces fitted
so well, each screw just dropped right into the hole perfectly centered to
thread into the part it mounted to. That was wonderful feeling. No more
filing out holes so things would fit together!

I haven't retrofitted my lathe yet, but I do want to!

Jon