New to CNC, Sherline Mill User

Ok, please pardon my total ignorance.

Bought a new Sherline ready to rock CNC setup. Loaded up the CNC software and played with the manual controls, came back inside to do some reading on the auto part of it and was lost. Finally figured out that the "Sherline Mill Inch" was TKLinux GUI, and that looks like one of the least popular GUIs.

Anyways been doing some reading, finally figured out how to home each axis and can run some of the loaded programs.

I guess my question is offsets and homing. Like I said I'm totally new to CNC and I'd rather not tear stuff up right off the bat.

Is there any certain place to home the axis, or does it depend on the file, like dead center or left rear position, or..........

How about offset, do I need to touch the stock with the tool and Home Z, or???

I can find very little info on the TK GUI, maybe I'd be better off switching to a more popular one??

Thanks for listening

Chris

Found this wiki
linuxcnc.org/docs/html/gui/mini.html

Maybe that'll solve my problems....

Homing is well covered here
linuxcnc.org/docs/2.7/html/config/ini-homing.html

Take the time to understand the diagrams.

Thank you.

Thanks. I been watching videos this morning on the subject and have a better grasp of the subject.

Sherline goes into pretty deep on the code and whatnot but never, hey lets load a hunk of aluminum and drill a hole in it.

The default setup for the sherline is to have no hard (ie mechanical limit switches = physical) or even soft (ie motion stops when an axis gets or expects to get to a predefined coordinate = virtual) limits.

Simplest way to get it all working is to manually jog the x and y to the middle of their range of travel, and the Z all the way up, then press home all (or home x, then y then z if the home all button is not there)

As there are no limits you can happily command the mill to move 100 inches in any direction and it will try to comply - bit of an issue when it runs out of travel! But for a newby, you will never get the annoying "will exceed axis limit" message which can be hard to figure out what is going on. Especially when you start to play with tool length compensation and the Z-axis.

But take care - you will stall the steppers at the end of travel if you exceed the real machine travel limits (the steppers are pretty small so x and y overtravel and z "up" overtravel will not damage anything) and may stuff up the part you are making as LinuxCNC will be happily still stepping away thinking everything is fine! Now overtravel in the z "down" direction with the cutter rotating is a different story - you don't want to mill thru the table!

After you are sort of happy with moving the machine aound, adding soft limits to the configuration is worth learning how, so at least when you hit "run" LinuxCNC will warn you that your g-code will try and exceed the machine limits - investigate, fix and try again!

I'm using the Axis interface, and I've set up the axes to be x=0 and y=0 at mid travel and Z=0 at bottom of travel, with home position being x,y at mid travel and the z at the top of travel
This gives travel in machine coordinates of -4.51 < x < 4.51 -2.21 < y < 2.21 0 < z < 6.81 and the soft limits are set to this.

The relevant bits from the config are (most of the config came from installing a clean install from the Linux CNC LiveCD and choosing sherline mill as the config - the limits and homing tweaks I put in myself)

This all works pretty well. The Axis interface is better than the TK one, as are the newer versions of LinuxCNC. The CD's that came with the sherline were for earlier versions of LinuxCNC (actually EMC2 at the time) and may still be dated.

When I finished prior to shutting off, I return the machine to the home location with the following G code
Which sets it ready for next time - turn on and hit "home all"
You can do lots of customisation of both the hardware and the software.
Adding spindle control is not too hard or expensive, and customising the GUI is not too hard either - I've attached a screen grab of my slightly tweaked Axis GUI.

Enjoy!