Rigid Tapping

Good. I was hoping that I could get by with the 64 CPR encoder.

While I do not know what the upper bound on tapping spindle speed is, I doubt very much that it is any where near 5000 RPM. So, it looks like I can get by with a dumb parallel port for starters.

Thanks!

-Wayne

jmelson wrote:

waynegramlich wrote:

Greetings:

I am planning on adding rigid taping to my mill.
-Wayne

Oh, one other area that you need to be concerned about. The Z axis needs to
be able to follow the spindle speed changes. So, either the spindle reversals
need to be moderated or the Z axis needs to have very quick acceleration.
I had to put a filter into the spindle speed commands to slow down the reversal
so the Z axis could keep up.

If you have a stepper axis setup, then it is a bit hard to know if there are
any velocity lags in your stepper drivers. So, it is just a little hard to know
exactly how well the axes are following the commands to sync to the
spindle.

Jon

I do have a stepper axis setup. I will dig around in my configuration file tomorrow morning and see what the Z axis acceleration is set to. It looks like I'll have to see how fast my spindle changes speed and try to do the math.

Does anybody know if there is a recommended speed for tapping aluminum for various common diameters and thread pitches -- 4-40, 6-32, 10-32, etc? I suspect that aluminum tapping speeds are faster than most.

Thanks for the insight and info,

-Wayne

waynegramlich wrote:

Does anybody know if there is a recommended speed for tapping aluminum for various common diameters and thread pitches -- 4-40, 6-32, 10-32, etc? I suspect that aluminum tapping speeds are faster than most.



-Wayne[/quote]
I answered this before but pushed the wrong button and lost the message.
I do 2-56 up to 6-32 holes in aluminum alloy at 1000 RPM, and 10-32 at
600 RPM. I use spiral flute taps for thin material, and spiral point for
deeper holes. Note that the manufacturer specifies something like
3X hole diameter for the safe depth for the spiral FLUTE taps. I think
you can go a bit deeper, but the flutes eventually clog if you go too
deep. I use combo drill-taps a lot, so I effectively spot, drill through and
tap with one tool. I have a program that takes in a file of XY coordinates
and generates the G-code for that operation.

I use alum-tap as the tapping fluid of choice, it works amazingly well for
tapping aluminum. I often get thousands of holes in sheet aluminum
out of one tap.

Jon

jmelson wrote:

waynegramlich wrote:

Does anybody know if there is a recommended speed for tapping aluminum for various common diameters and thread pitches -- 4-40, 6-32, 10-32, etc? I suspect that aluminum tapping speeds are faster than most.



-Wayne

I answered this before but pushed the wrong button and lost the message.
I do 2-56 up to 6-32 holes in aluminum alloy at 1000 RPM, and 10-32 at
600 RPM. I use spiral flute taps for thin material, and spiral point for
deeper holes. Note that the manufacturer specifies something like
3X hole diameter for the safe depth for the spiral FLUTE taps. I think
you can go a bit deeper, but the flutes eventually clog if you go too
deep. I use combo drill-taps a lot, so I effectively spot, drill through and
tap with one tool. I have a program that takes in a file of XY coordinates
and generates the G-code for that operation.

I use alum-tap as the tapping fluid of choice, it works amazingly well for
tapping aluminum. I often get thousands of holes in sheet aluminum
out of one tap.

Jon[/quote]

Jon:

Thanks for the great info. That is exactly the kind of information I needed.

Again, thanks,
-Wayne