[jgarner77]

Hi not sure if this is the right place to post but here goes I am trying to remove the burr on the back of a thread I'll try and give as much information as I can the thread is an external 8un thread obviousley imperial but is programmed in metric as most of our operators putting it nicely struggle to comprehend imperial as almost all our parts are metric.

Sorry for my babbling as i've said the thread is 8un external and is programmed

G97S300M3
G00 X107.696 Z2.54 M8
G76 P020000 Q230 R0.0
G76 X104.106 Z-59.69 P1803 Q230 F3.175

At the back of the thread is a groove and the back face is at Z-63.5 I am using a 3mm wide L/H grooving insert to machine out the groove and the same tool to clip the thread both the groove and threading tools are set from the front edge of the insert on the front face of the job I just can't seem to find the right starting position to get the groove tool in the same lead as the thread tool I know the distance between the front edge of the threading insert and the cutting edge is 1.6mm so i'm trying to allow for that aswell but have just ended up with figures running around in my head and a burr at the back of the thread i'm using a right hand threading tool threading towards the chuck and a left hand grooving tool away from the chuck for the clipping operation

Thanks in advance for your replies and if you need anymore info i'll be happy to give whatever I can

[txcncman]

Trial and error. Change Z start point for different degree rotation. Try G32 cycles with motions on X as well as Z. Some machines can use P word to specify degree start point.

[jgarner77]

Thanks for reply as it stands I am using a sub program to clip the thread going from the major dia to the minor dia my program looks likes this

In main program

G00 T1111 (3MM L/H GROOVE TOOL)
G97S300M4
G00 X110.0 Z2.0 M8
Z-62.0
X107.696
M98 P100040 (repeat sub program O0040 x10)
G00 X150.0
X250.0 Z150.0 M9
T1100 M1

(SUB PROGRAM O0040)

G00 U-0.359
G32 Z-60.0
U10.16 W2.794
G00 U1.0
Z-62.0 (Back to start pos' n)
U-1.0
U-10.16
M99

I use this method on a smaller version of the same part and it works a treat but can't for the life of me get it to work on this one as you can see i've included start and end figures in my programs but these are just random figures somewhere close to where it should be to show you what i'm doing and how i'm doing it as you can see it takes 10 passes at an ever increasing 0.359mm taking it to the minor diameter of the thread the u and w figures are taken from the smaller part program and I use the same principal to clip the front of the thread but using a right hand grooving tool but is a lot easier to set up cause I just start my grooving tool 1.6mm further back from where my threading tool starts allowing for the difference from the front of the threading insert to the cutting edge of the threading insert

Thanks again any and all help greatly appreciated