Centroid Community CNC Support Forum

I am continuing my setup of my King-Rich mill (Bridgeport clone) and have set up auto homing of the X Y and Z axis.
I am using the knee, rather than the Quill for my Z axis, so I have set it to home in a negative direction (down).
This all works well when using the automatic homing sequence, but I think it would be nice if, aftert homing, the knee could move up a bit, to make it faster to run a job. Most of the things that I work on, wouldn't need the knee to start off all the way down.
I'm sure this has been asked before, but I'm not sure which search terms to use when looking for this answer

The home file is just a G-code file. You can add any move in there you want. After the G26 /Z line, just add a G0 Znnn line to move it to whatever coordinate you want

Yep, but after a change select custom home in the Wizard, so it will not be overwritten each time you use the Wizard.

Uwe

Thanks Tom and Uwe, I was a bit slow of thinking today an obvious answer. Thanks again.

I am using the knee, rather than the Quill for my Z axis, so I have set it to home in a negative direction (down).

If your Z axis moves the knee of a knee mill, then the Z-plus direction (e.g. M92) should be knee-down.

Regardless of machine mechanical layout, the Z-plus direction should move the tool tip farther away from the workpiece, and the Z-minus direction should move the tool deeper into the workpiece.

If you set up your control backwards (Z-plus moves the knee up, bringing the workpiece closer to the tool) then you will find you cannot use canned drilling cycles, nor any standard post-processor, including Intercon's.

It sounds like I have made a rookie mistake then, Cncsw. Thanks for that! I'll add it to my "to do" list in my New Build thread!

Today I am attemping to setup up my milling machine homing, based on cncsw's comment above: "If your Z axis moves the knee of a knee mill, then the Z-plus direction (e.g. M92) should be knee-down.".
Here is my current Acorn inputs screen: ....and here is my Homing and travel screen: I have tried to change this a couple of times, and keep ending up with no Z axis movement, however when I restore a report, Z works again.
Rather than providing details of what I have set wrongly, what is the correct setup of these 2 screens, bearing in mind that I am moving the knee, rather than the quill?
Thanks again for your help.

By using the Acorn wizard to reverse the Z axis motor direction, I was able to get the positive home switch to be the lower limit switch on the knee's travel. My input definitions and Homing type now look like this - The Z axis now homes to the lower position and the lower knee switch is the positive one.
This seems to have also affected the X axis, I haven't yet worked out why, but the X axis now homes to the LHS of the mill (operator's RHS) and what was the positive switch on the X axis is now the negative switch and vice versa..

I swapped the inputs around for the X axis and it now homes the X axis to the RHS of the mill. Why it changed is still unknown, but it seems to be fixed.
Here is a photo of the mill in its home position. The machine coordinates for this position are: X: 0 Y: 0 Z: 0 Feel free to tell me if this isn't right.