Anyone have a edge finder G-code routine?

I don't have homing switches on my mill, and I am thinking about writing a G-code routine to make it easier/faster to set 0,0 to one of the corners of the fixed jaw.

Am I re-inventing the wheel here? Anybody have something like this already?

-Jeff

Here's what I ended up doing... I created a edge find verification tool. I try to leave the bit parked over the corner of the vise every night. This code can verify location after re-start.

Posted for deskcnc, this code should be verified carefully and safely on your machine if you wigh to use it... yadda yadda...

-Jeff

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(Created 6:29:19 PM 9/19/2006 from edge-find-right.dxf)
(Post = ISO G-Code - Non Modal)
(Tool 0 = Tool Reset)
(Visually place the edge finder centered on the corner of the vise and slightly above the top of the jaw)
(Then zero the XYZ)
N0001 G90
N0003 T0 M06 S10000
N0005 G00 Z0.0500 (come up a bit)

N0007 G00 X-0.1000 Y-0.2000 Z0.0500 (move to front of vise jaw)
N0009 G00 X-0.1000 Y-0.2000 Z-0.2000 (go down)
N0011 G01 X-0.1000 Y-0.1010 Z-0.2000 F5.00 (approach vise, not quite to edge)
N0013 G04 P.5 (dwell with edge finder hopefully NOT offset)
N0009 G00 X-0.1000 Y-0.2000 Z-0.2000 (pull back)
N0011 G01 X-0.1000 Y-0.0990 Z-0.2000 F5.00 (approach vise, hopefully to edge)
N0013 G04 P.5 (dwell with edfinder hopefully offset)
N0015 G00 X-0.1000 Y-0.2000 Z-0.2000 (pull back)

N0017 G00 X0.2000 Y-0.2000 Z-0.2000 (move outside of vise jaws)
N0019 G00 X0.2000 Y0.1000 Z-0.2000 (move back)
N0021 G01 X0.1010 Y0.1000 Z-0.2000 (approach vise, not quite to edge)
N0023 G04 P.5 (dwell with edge finder hopefully NOT offset)
N0025 G00 X0.2000 Y0.1000 Z-0.2000 (pull back)
N0027 G01 X0.0990 Y0.1000 Z-0.2000 (approach vise, hopefully to edge)
N0029 G04 P.5 (dwell with edge finder hopefully offset)
N0031 G00 X0.2000 Y0.1000 Z-0.2000 (pull back)

N0033 G00 X0.2000 Y0.1000 Z0.05000 (pull up)
N0035 G00 X0.000 Y0.000 Z0.0500 (go home)
N0036 G00 X0.000 Y0.000 Z0.0000 (go home)
N0037 M05
N0039 M02

Dosen't your mill have a hand pulse generator (handwheel)?

It has a keyboard, but I need to put it in an easier location to work with. The other thing is that DeskCNC doesn't switch easily between jog speeds.

-Jeff

So how does it work? I'm guessing that you stop it when it's close? or run in single blk.?

That's what I was thinking originally, but now it is a "confirmation" zero. If it doesn't break, then breaks on y and then doesn't break, and breaks on X then I'm +/- .001".

So, if it breaks, breaks on y, I'm too high on Y and I need to move the edge finder closer to me and try again.

It starts and ends at zero, zero.

Normally, I park the axis at zer, zero at night, so I can hit it in a few tries.

I may try it with pausing instead at some point, but this works for now.

-Jeff