Hi Brian,

sorry that it took so long...

The problem occurs when you are using metric units. An example (like attached as tangential.xml):

The resolution of my x and y axis is 400 steps/mm. The resulting maximum feedrate is 1500 mm/min.

The resolution of my a axis is 14.4 steps/degree (in normal mode). The maximum feedrate is 8000 degree/min (even more, to be honest...).

The resolution of this axis in tangential mode is 5184 steps/rotation. The maximum feedrate is 60 rotations/min.

Now my problem in tangential mode:

When I try to cut with a feedrate of 1000 mm/min and the defined maximum feedrate of my rotation axis is ignored (in tangential mode) Mach3 tries to rotate this rotation axis with 1000 U/min. Doesn't work of course...

The only chance was to manually reduce the feedrate down to 60 (my defined maximum speed for this axis).

That also means the x and y axis also move only with 60 mm/min which is much too slow.

Art wrote that defining the tangential axis in steps/rotation is for technical reasons.

But ignoring the defined maximum feedrate results in a big problem here.

It must not be ignored for the tangential control to work imo.

Now switch to imperial units (like attached as inch.xml):

The resolution for x and y now is 10160 steps/inch.

**The resulting maximum feedrate now is 60 inch/min!!!**The setting for the tangential axis remains the same: maximum feedrate is 60 rotations/min.

When I try now to cut with a feedrate of 40 inch/min everything works fine!!!

The problem is that you have to use the same feedrate for axes that are configured differently (mm/min, degree/min, rotations/min).

If you are using imperial units (and I suppose you do

) the maximum feedrate settings are almost identical.

But not if you are using metric units!

And I didn't like to switch to imperial units, because we are living in a metric world here in Germany

.

A feedrate scaling factor that compensates the differences of the different used units for linear and rotation axes would be very helpful.

A similar problem occurs when milling different workpiece diameters with a "normal" rotation axis. As far as I understand this can be compensated with the radius correction feature which appears right to DRO of a rotation axis.

Kindest regards

Norbert ( aka rubens...)