From what I understand, it's the top of the sensor on the "X". They're nice and compact.

 

Those are nice looking switches

 

I'm not sure if you're talking about the inductive sensors or the Temco switches but I'll add an eBay link to the sensors.

 

So I did some testing and these sensors do trigger with aluminum. They have to be very close. I wanted to also say that anyone who uses these should make their "trigger" object so it passes over the top of the sensor as opposed to a trigger that would approach directly at the sensor. This is to prevent the machine from actually crashing in to the sensor during a fast move. Anyway, these little sensors are pretty slick and their almost completely protected from chips & coolant. There are a couple ways to install them but you just have to make sure and protect your controller. I will be using an inline diode. Hayri (Phoenix CNC controller designer) recommended these to me and the price is very affordable.

 

To allow safe operation of these switches @ 12-24v

 

The switches operate just fine by themselves at that voltage range but my controller (essentially an Arduino uno) can't handle this voltage on this circuit. This is what Hayri recommended.

 

These sensors have 3 wires. Here's the recommended Arduino UNO wiring diagram using the 1N4148 diode.

 

Hey thanks dude. I plan on making these adjustable but I am wondering if aluminum chips can trigger the sensor. For the most part, my X and Y axis will be protected. I actually need to be working on protective covers for the Z axis rails.

 

So I was trying to figure out what it would take to install those red inductive sensors and they were actually going to require some teardown and modification of some parts. This is mainly because of the sensor detection area in relation to how they need to be mounted. I found a lower profile version of the same sensor on Amazon. They are more expensive but, at this point, I really don't want to tear this machine apart any more. I just decided to spend the money to avoid this. There are cheaper versions of this low profile sensor on eBay but they would be on the slow boat from China. Also, these new sensors have a detection area in a better location for my purpose.

 

Installed the limit sensors this weekend. Unfortunately I had to disassemble half the machine to make clearance for them. It's become a fair amount of work to do so I hope this is the last time I need to tear it down.

 

Thank you Julius. Happy Holidays!

 

Awesome dude! I made my z axis back plate with a series of holes to allow for adjustment. How is that low profile milling vise working for you?

 

Hi Todd,
So the machine design changed a couple times before I actually built it. I was trying to bring the centerline of the spindle back towards the center of the Y axis linear carriage blocks (which I didn't completely accomplish). So if you look at the X plate ,that the Z axis mounts to, you can see it rides very close to the extrusion behind it. If I had placed the X linear rail facing forward, the spindle and Z axis would be located with more "stickout". Also, the lower X axis is actually facing forward but it is stepped back from the upper extrusion to support what I mentioned above. It's a little hard for me to explain all of this but I think it will work out.