DIY Z axis 0 plate. It works perfect!

[balsaman]

Someone on here mentioned that the Shop bot comes with a Z axis zeroing tool made up of a plate that you set on your material. You run some kind of "Zeroing routine" and the tool comes down an touches the plate and calculates the material top of stock location and sets the tool zero to be at the top of stock.

Well I made my own, and it's so simple it's silly.

I made a small .125" thick plate from aluminum. I took the +5 volt wire off my Z axis home switch, extended it and tied it to the plate. I set my z home switch in turbocnc.ini file to normally open and the home offset to .124". My router has an aluminum body so it is grounded.

To set the tool height, I chuck in the tool, set the little plate on my material, under the tool, then I home the axis. The z axis slowly moves down towards the plate. When it touches the plate, it stops, thinking it hit a NO switch, and sets the z height to .124". The 1 thou difference seems to be the time it takes for the tool to stop. I raise the tool, remove the plate, and if I send the z to 0" it stops perfectly on the top of the materail every time. I han just barely slide the material out from under the tool, it leaves just the slightest mark. I love it.

I will make a plastic pocket, attached to the z axis to hold the little plate so it can ride along and be insulated from things while not in use.

Here is a picture

Eric

[radio-op]

Way Cool! Have to use this idea.
Bill

[mvaughn]

Definitely cool!

I one of those things where you say "Doh, why didn't I think of that!"

Good work Eric.

[mvaughn]

I'm probably stating the obvious but for those with insulated routers, you could rig up an aligator clip to attach to the bit.

Or would this be electrically harmful to something?

[balsaman]

That would work fine.

Eric

[barbwirebi]

Great Idea !!!
I will have to do this

[wjbzone]

Great idea Eric.
If the tool overtraveled into the plate, you could design a spring loaded the plate to allow for that.
Bill.

[turmite]

Eric would you mind me showing my tool set switch here? I will have to get it photographed. I tried one photo and the light was not good enough? My switch is a different animal completely so it will at least give a variety, .....just say the word.
Mike

[krsykes]

I've also done something like this with my 'nearly completed' machine. I've done a permenant
system, where I've constructed a spring loaded touch sensor just to the side of the table. This
sensor is exactly the same height as the spoilboard, so after I've flycut I can adjust the sensor
accordingly. The feed is to pin 11 of Mach 2 and ground is through the frame (the spindle is double insulated). I'm about to run a macro the moves the tool to the sensor. The only thing I haven't worked out yet, is how the automatically set the height when it touches. Apparently I should use the 'digitise' method. Has anybody done this in Mach 2?

I'll post some pictures of the machine in a few days or so. I'm rather proud of it.

[balsaman]

Turmite, go ahead.

Krsykes, I would like to see some pictures

Eric

[Bloy2004]

Nice idea Eric


as for my impatience and related promised pics...
It's been an hour now and no pics posted yet!

[NeoMoses]

Very nice simple implementation. What Feedrate do you use when probing the tool? I would imagine that with this system, the slower you run it down the more accurate it will be.

A little spring loaded system like they use on the big machines would be nice to keep from breaking bits in case they touched down a bit hard, but you're not making this for Joe Schmo, you made it to make your life easier. You know, the more I look at this system, I am in love with it's simplicity.

Great job on a very useful tool!