Need thread cutting help

[Larry Myers]

Hi all,
I posted this in the G-Code section as well.
I am looking for some advise concerning internal thread milling. I have a Sharp 2412 VMC. Fanuc oi.
I am wanting to thread a 1”-8 hole, 1” deep. (aluminum) I have the hole already bored out to 7/8”.
I have a 6 flute single point carbide bit that is 0.695” dia. I wasn’t going to use cutter comp to begin with. Below is the part of the program that I am having trouble with:

T4M06(THREAD MILL);
G00G17G20G40G80G90;
G54X0Y0M03S1000;
M08;
G43H4Z0.1;
G01Z-1.0F20.;
X0.150F10.;
G91G03X0.15Y0I0.15Z0.125F10.L10;
G01X0Y0M09;
M05;
G00G28G91Z0;
M30;
%

I think my problem is in the feedrate however I am not sure what to do. Thanks in advance for any help!

Larry

[samdog]

use i and j and start from bottom of hole and bring tthe z up in 1/2 truns