[g-codeguy]

Mr. James Weed's last post, "converting ipm to dpm macro question?" reminded me of my ignorance.

We have a part that was programmed by the seller of our lathe. 17 degree helix over .34 length. Our first ever C-axis program, and obviously not as easy to figure as drilling holes.

His 6 passes were based on these figures.

G98X.5Z.25C25.5
G1X.14F100.S5000
Z.14F10.M88
Z-.495C0F600.
G0X.5

This resulted in about an 8 degree helix, but was used by a sister company like this. So I have to assume it was doing its job as we never got any parts back or rejections. However, last time it was set up, I figured why not make it right?

I wound up with this.

G98X.5Z.05C52.
G1X.145Z.015F100.S5000M88
Z-.62C0F1500.
G0X.5

How does one go about figuring the feedrate for C-axis rotation? I used cycle time and eyeball to get my modified program to cut at about the same feedrate. I have no idea where to start looking for this information.

Thanks.