negative rpm's

[Estop]

Can anyone tell me why or of what use it is that when in the define tools and upon the parameters tab, if ccw is selected for spindle rotation, then when the box is closed and I'm back on the tool parameter sheet for an operation the spindle speed will then have a negative value. This caused one of my posts to output negative rpm's, which the control didn't like too well. I have the post modified to compensate for this nifty feature, but I'm just wondering why it exists.

[KMaynard]

I think for left handed taps and drills

Kev

[Luther_Heggs]

Left handed taps (or any other tool that wants the spindle to go ccw).

[Estop]

Thanks for the replys. I understand left hand tools, but what I'm puzzled about is the minus sign before the spindle speed. My post based on mpfan.pst ignores it and codes out Sxxxx M04, but one based on mphur.pst (for a hurco control) posts out S-xxxx M04, which is what is appearing in the spindle speed edit control. This happens in V8.0 and V8.1 both. However it Only happens if the tool icon is accessed by right clicking from the tool parameter sheet of the operation. Thanks again for the replys.