Adding second Z touchplate for tool height offsets

[ryanjg11]

I have a 4x8-foot gantry style CNC router with an ATC spindle, and I'm just now getting around to designing my fixed toolrack. Right now, I'm using one Avid touchplate to set tool height offsets, as well as the Z0 position at the top of my workpiece. I should also add that I have a vacuum table with an MDF spoilboard which will be routinely surfaced, creating a problem when I want to add additional tool height offsets as the touchplate will no longer be the same Z distance from the spindle Z home.

As I see it, I have two options right now:

• Build a rigid cradle for the Avid touchplate on the new fixed toolrack. This rack will stay a constant position from spindle Z home and set tool height offsets. I can also remove it from the cradle and place at the top of my workpiece when I need to set Z0, though this is going to be a bit of a pain as my workpiece XY0 tends to be on the opposite side of the machine. I can design this from 1/4" 5053 aluminum, laser cut, TIG weld it, and attach it to the 40x80mm tool rack extrusion.

• Purchase a second tool touch off like this model and dedicate it to setting tool height offsets only. I can keep the Avid touchplate on the other side of the machine, closer to where I normally set my workpiece height. This touch off plate also does not require a separate clamp wire like the Avid touchplate. I know it's possible to rewire the Avid touchplate to eliminate the clamp wire, however my ATC spindle does have ceramic bearings so I'm not sure if it's conductive. I need to do further testing here.

Would it be possible to accomplish scenario two without having to rewire the internals of my control cabinet? I stumbled over this YouTube video showing someone adding a second touchplate using a micro-connector Y splitter. Would this approach work for me?

[swissi]

Would it be possible to accomplish scenario two without having to rewire the internals of my control cabinet? I stumbled over this YouTube video showing someone adding a second touchplate using a micro-connector Y splitter. Would this approach work for me?

If you get the TT model you posted (NO type) you can connect both the AvidCNC plate and the TT to the same input on the Acorn board.

The ProbeApp will support your AvidCNC plate for WCS Zero settings and your TT for tool height offset measurements perfectly.

-swissi

[riggsp]

What Swissi said...works great!

[ShawnM]

I also use two NO optical touch off plates wired to a single input for my tool change macro. One movable and one fixed.

[Ken Rychlik]

I have had several machines and I modified the flycut file to adjust the tool measure offset at the end of the file. So after taking .010 off of the spoildboard, it adjusted the switch automatically at the end.