Hi all,
Fine tuning my mpcnc, I am now looking at a Z probe, was thinking to use spark plug feeler gauge, as they are calibrated, and everyone has one in is car toolbox!
If my understanding is right, i wire one of the feeler gauge to the Z min signal pin, and a crocodile clip on the too bit connected to the (-) negative Z min pin?
Just confirm I am not going to f**k it up! 
Yes, perfect Z probe.
I’ve been wondering about using a sheet of aluminum foil and doing a mesh bed level… You’d probably want to have some method for holding it down though.
Was thinking about it too, but how to keep it perfectly in contact with the spoilboard?
spray glue?
You might be able to just use water to get it to stick in place. Glue isn’t liable to be good since it’ll stay behind when you pull the foil to start your actual cuts.
As long as the spoil board isn't mdf...
Yeah, when you put water on MDF you end up having to wait a long time for it to dry then longer yet for the resurface to finish. 
Saran wrap first, then water for the foil to stick to or just wax the surface before sprinkling?
Or just fit a switch to the spindle. Though honestly I’m not sure why you’d want to probe the whole bed anyway. Just surface it and be done with it.
Or you can simply use Aluminum tape. I did a couple of times for cutting really big vynil stickers, since I didn’t trust my leveling and I used a different mdf board to hold them. It works well enough, and it’s quick to apply.
Not that easy to remove though, so that may be an issue.
You all have me thinking…How about putting several pieces of aluminum tape at the 9 or 16 or however many mesh points to want to use? Maybe router a little groove for a small wire to connect them all?
What type of solder did you use? Also aluminum wire?
I just made one of these to go with my dual endstop install. At first it wouldn’t stick even after degreasing and scuffing, but I cranked up the heat on my (Hakko) soldering iron and focused on just getting solder on the gauge. It eventually took a small spot of solder and then I was able to attach a pre-tinned wire to it. I guess the key is the gauge needs more heat than the copper wire. Once the solder is on the gauge you don’t need such high heat to bond the wire to it.
Now I’m trying to figure out the best quick connect and cable management.
Yes, the gauge has enough mass to act as a pretty good heat sink. That’s what my 140W soldering gun is for.
Propane torch works pretty well too.
