Left hand tapping

[Get lucky]

I am trying to tap a left hand 7/16-20 tap in kia turn21 with a fanuc oi-TB


This is what I do for a R.H. tap

(7/16-20 SPIRAL TAP R.H.)
G97S200M3
G0X0Z.2T1010
M129S200
G84Z-1.75F.05
G80M9
M128
G28U0W0T1000



This is what I tried for a L.H. tap and did not work

G0T1000M8
(5/16-18 CUT TAP L.H.)
G97S200M4
G0X0Z.2T1010
M129S200
G74Z-1.5F.05
G80M9
M128
G28U0W0T1000

Any input would be appreciated

Kyle

[beege]

Why would you change from G84 to G74? All you needed was a change in spindle direction? I' not familiar with the machine, either, or what G74 does differently than G84. Good luck!

[ikneb]

When using G74 start your spindle M03 for lefthand taping ,freaks out the boss
good times!

[maz43]

You could try G32 instead if you have a TC tap holder.
Then just reverse spindle directions.
Works in my older Kiaturn21 as I don't have G84 or G74.

[Jawbreaker38]

I'm assuming you're doing this in a lathe, and G74 is left hand tapping for a mill. I don't remember the code for left hand tapping in a lathe, but the G32 will work.

[toolsrul]

Your feed needs to be .055" (1/pitch) since that is governed by the tap. 18 is a little more coarse then the 7/16-20. Plus you don't explain why it doesn't work.

[Get lucky]

Begee,
G74 just seemed logical to me never had to program for a L.H. tap before so I figured I would give it a try. G74 is a milling L.H. tapping cycle

maz43,

No TC holder not sure I understand what a TC holder is I think you are talking about a floating head holder.

jawbreaker38,

Yes this is on a lathe, I was reading in the fanuc book and it says that I should be using a G84 just change from a M3 to a M4 didn't work

toolsur,

were is your math from 1/20=.05, 1/18=.055. I'm not sure I follow what you are trying to get at.

Here is my problem in more detail


G0T1000M8 (change turret to station 10)
(7/16-20 CUT TAP L.H.)
G97S200M4 (spindle starts in revers)
G0X0Z.2T1010 (turret positions in front of the part)
M129S200 (spindle stops )
G84Z-1.5F.05 (spindle starts in foreword and turret feed Z- and then spindle reverses and turret feed Z+ back to start position)
G80M9 (cancel G84)
M128 (cancel M129)
G28U0W0T1000 (send turret to home position)


The fact that on the G84 line it doesn't start as a M4 doesn't work for me and I'm not sure how to make it start as a m4


Thank you
kyle

[ProProcess]

this is a long shot but try M129-200

[Jawbreaker38]

Ok, I guess I'm not getting the M129 command, for rigid tapping I assume? I would've thought that it was M29. I'd go with the G32 method, and I'm sure you will have no problem in rigid mode if done correctly.
I'd do it like this-
G00 G18 G99 T202 S500 M04
X0. Z.1 M08
G32 E.0556 Z-1. M05 (use E or F on this line and put the M05 on this line)
G32 Z.1 M03
G00 Z1. M09
G28 U0. W0. M05
M01

The M05 command will be read last, so it will be performed when the tool has reached it's depth. I neglected to pay attention to the pitch of our thread, but this is just an example anyway.
Hope this helps.

[beege]

My 10TF manual mentions G84.1 as left hand tapping function...

[ProProcess]

My Haas lathe uses G84 Forward Tapping Cycle and G184 Reverse Tapping Cycle. My old Fanuc controlled mill used G84 Forward and G74 Reverse. I would bet that there is a similar Gcode in there to do what you need.
Good luck and post your findings here as I'm sure they would be usefull down the road.

[Get lucky]

Proprocess,

M129-200 resulted in a illegal us of negative sign

Jawbreaker,

The G32 worked but snapped the tap in the bottom (bound up chips) of the hole so I tried to run the tap half way in and then to full depth but got a miss match thread. When I ran the the other side witch was 7/16-20 R.H. I had allot higher quality tap available to me, nobody makes a good quality tap in a L.H. that will tap to full depth.

begee,

G84.1 resulted in illegal G-code

The M129,

This is what I have have found out on the M129. I was not sure what it was for myself until I was looking threw the fanuc book and I found the section 4.22 (parameters of rigid tapping ) in the the parameter manual.

Parameter #5210 (Rigid tapping mode specification M code)
[data type] byte
[valid data rang] 0 to 255

This parameter sets an m code that specifies the rigid tapping mode.
To set the M code larger then 255, set it to parameter No.5212
NOTE:
1 The M code is judged to be 29 (M29) when "0" is set.
2 To use an M code whose number is greater than 255 specify the code number with parameter No.5212

Parameter #5212 (M code specifies a rigid tapping mode)
[Data type] 2-word
[Unit of data] Integer
[Valid data range] 0 to 65535

This parameter sets an m code that specifies the rigid tapping mode.
The M code that specifies the rigid tapping mode is usually set by parameter 5210. To use an M code whose number is greater then 255 specify the code number with parameter 5212.
NOTE:
If the setting of this parameter is 0, the M code specifying the rigid tapping mode is determined by the setting of parameter 5210. Otherwise, it is determined by setting of parameter 5212. The setting of parameter 5212 must always be within the above valid range.


parameter #5210 is set to 129
parameter #5212 is set to 0

So if what I read there and copied to this thread means the same thing to you as it did to me, well that is were the M129 came from as for the M128 to cancel have not found that yet.

Thank you everybody this is a pain in the @ss
Kyle