Thread Mill Wizard - Slanted thread produced

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07-22-2012, 01:58 AM
ngr1

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Thread Mill Wizard - Slanted thread produced

Hello, every time I try to use the thread Mill Wizard for a ball nut the thread produced is sharp and a great fit but it is always slanted. Pictures and g-code below, I am beginning to think it maybe my MACH setup as I have seen many do this. I did check to ensure the TAIG mill is square

Any help would be appreciated. . Thx.

---------Thread Milling G-Code---------------------------------
G0 G49 G40 G17 G80 G50 G90
M6 T0 (TOOL DIA. 0.65)
G20 (Inch)
M03 S0
G64
G00 G43 H0 Z0.1
(Right hand ID Conv)
X-0.3075 Y0.37375
G00 G42 P0.325 X0.06625 F10
G00 Z0.0313
G02 X0.44 Y0 R0.37375
G02 X-0.44 Y0 R0.44 Z0
G02 X0.44 Y0 R0.44 Z-0.0313
G02 X-0.44 Y0 R0.44 Z-0.0625
G02 X0.44 Y0 R0.44 Z-0.0938
G02 X-0.44 Y0 R0.44 Z-0.125
G02 X0.44 Y0 R0.44 Z-0.1563
G02 X-0.44 Y0 R0.44 Z-0.1875
G02 X0.44 Y0 R0.44 Z-0.2188
G02 X-0.44 Y0 R0.44 Z-0.25
G02 X0.44 Y0 R0.44 Z-0.2813
G02 X-0.44 Y0 R0.44 Z-0.3125
G02 X0.44 Y0 R0.44 Z-0.3438
G02 X-0.44 Y0 R0.44 Z-0.375
G02 X0.44 Y0 R0.44 Z-0.4063
G02 X-0.44 Y0 R0.44 Z-0.4375
G02 X0.44 Y0 R0.44 Z-0.4688
G02 X-0.44 Y0 R0.44 Z-0.5
G02 X0.44 Y0 R0.44 Z-0.5313
G02 X-0.44 Y0 R0.44 Z-0.5625
G02 X0.44 Y0 R0.44 Z-0.5938
G02 X-0.44 Y0 R0.44 Z-0.625
G02 X0.44 Y0 R0.44 Z-0.6563
G02 X-0.44 Y0 R0.44 Z-0.6875
G02 X0.44 Y0 R0.44 Z-0.7188
G02 X-0.44 Y0 R0.44 Z-0.75
G02 X0.44 Y0 R0.44 Z-0.7813
G02 X-0.44 Y0 R0.44 Z-0.8125
G02 X0.44 Y0 R0.44 Z-0.8438
G02 X-0.44 Y0 R0.44 Z-0.875
G02 X0.44 Y0 R0.44 Z-0.9063
G02 X-0.44 Y0 R0.44 Z-0.9375
G02 X0.44 Y0 R0.44 Z-0.9688
G02 X-0.44 Y0 R0.44 Z-1
G02 X0.44 Y0 R0.44 Z-1.0313
G02 X-0.44 Y0 R0.44 Z-1.0625
G02 X0.44 Y0 R0.44 Z-1.0938
G02 X-0.44 Y0 R0.44 Z-1.125
G02 X0.44 Y0 R0.44 Z-1.1563
G02 X-0.44 Y0 R0.44 Z-1.1875
G02 X0.44 Y0 R0.44 Z-1.2188
G02 X-0.44 Y0 R0.44 Z-1.25
G02 X0.44 Y0 R0.44 Z-1.2813
G02 X-0.44 Y0 R0.44 Z-1.3125
G02 X0.44 Y0 R0.44 Z-1.3438
G02 X-0.44 Y0 R0.44 Z-1.375
G02 X0.44 Y0 R0.44 Z-1.4063
G02 X-0.44 Y0 R0.44 Z-1.4375
G02 X0.44 Y0 R0.44 Z-1.4688
G02 X-0.44 Y0 R0.44 Z-1.5
G02 X0.44 Y0 R0.44 Z-1.5313
G02 X-0.44 Y0 R0.44 Z-1.5625
G02 X0.44 Y0 R0.44 Z-1.5938
G02 X-0.44 Y0 R0.44 Z-1.625
G02 X0.44 Y0 R0.44 Z-1.6563
G02 X-0.44 Y0 R0.44 Z-1.6875
G02 X0.44 Y0 R0.44 Z-1.7188
G02 X-0.44 Y0 R0.44 Z-1.75
G02 X0.44 Y0 R0.44 Z-1.7813
G02 X-0.44 Y0 R0.44 Z-1.8125
G02 X0.44 Y0 R0.44 Z-1.8438
G02 X-0.44 Y0 R0.44 Z-1.875
G02 X0.44 Y0 R0.44 Z-1.9063
G02 X-0.44 Y0 R0.44 Z-1.9375
G02 X0.44 Y0 R0.44 Z-1.9688
G02 X0.06625 Y-0.37375 R0.37375
G00 G40 X0
G00 Z0.1
M5 M9
M30
07-22-2012, 07:26 AM
Superman

Your tool (Ø0.65") seems too large for the core diameter of the hole
- as 1 single cutting edge leads into ( & out of) the vee of the thread, it should not be cutting on the flanks of the thread, other than at the tangent point

---side query, is the pitch correct ? 16 TPI ?? :confused:
-- 5/8" UNF is 18 TPI , core Ø = 17/32" (0.578125")
-- 3/4" UNF is 16 TPI , core Ø = 11/16" (0.6875")
07-22-2012, 04:09 PM
ngr1

Thanks superman.

My cutter is 3/4" 60 degree cutter and I am trying to follow the example from Hoss. Refer to the video below and forward to the 2:00 minute mark to see the MACH3 screen. I see that Hoss has the max diameter as .9375 which I will try. My hole size before milling is also .880".

[ame=http://www.youtube.com/watch?v=Suwl_HzouVU&feature=player_embedded]G0704 Economically Threadmilling a Ballnut Mount - YouTube[/ame]
07-22-2012, 04:20 PM
Geof

I did check to ensure the TAIG mill is square....

Not square enough. Did you tram it to the to the table with an indicator.

Alternatively your workpiece was not held level.
07-22-2012, 05:26 PM
ngr1

Thanks for the feedback Geof. I thought the same thing but I have also tried surfacing the material with a fly cutter first then milling the hole and then cutting threads. I am also placing the plastic sheet over 1-2-3 blocks and then clamping it down. The slant is really pronounced which I have never noticed in other machining operations.
07-22-2012, 07:23 PM
Geof

I am not really familiar with those small machines but from your pictures it seems you have a quill that moves up and down as well as ways on the column for the entire head to move up and down.

When you tram the spindle by rotating an indicator on an arm you are checking that the spindle axis is perpendicular to the table. However, this does not directly check that the column is perpendicular also. The spinlde axis and the column may not be parallel so you can have the spindle true which means you can face things correctly but if the spindle is not true then the machine will not interpolate holes perpendicular to the machined face.

This could be the case on your machine.