Re: [CAD_CAM_EDM_DRO] New to servos, please help/advise?

C.S. Mo wrote:

>My understanding, from the recent long discussion here, is that in order
>to do thread milling, you will need control over the spindle as well as Z.
>
>

No. Rigid tapping or lathe threading require spindle position information.
Thread milling does NOT require any spindle information, just the right
movement of the X, Y and Z axes together. Conventional thread milling
uses cutters that look like taps until you look closely, and discover the
"threads" are not a helix, but just rows of teeth spaces at the thread
pitch.
These tools are quite expensive, often costing over $100 each, and they
can only be used for a single thread pitch!

For home shops, I recommend the "single row" thread mill, which can be
used over a wide range of thread pitches. They do a fine job, and leave
VERY pretty looking threads.

For threading a large number of small holes, I have used a Procunier
CNC tapping head, which is a great invention. It has clutches activated
by axial pressure on the tap. You need to know spindle speed fairly
accurately to calculate the correct feed rate. The Z axis is fed into the
work the required distance, and then withdrawn at twice that feedrate
(as the reversing clutch spins the tap twice as fast in reverse). It taps
holes at about 1 per second.

Jon