Euclid Probe

Euclid was a Greek mathematician who studied geometry. It seemed fitting for the probe that studies the plane.

A highly accurate, magnetically coupled Z-Probe that is not affected by bed temp, bed material, magnetism or surface treatment. Capable of operating up to 80C natively (higher temp versions are a custom option at this time).

The probe can be configured to be used as a Z-probe, an endstop, or used as both.

Euclid Probe can be manually or automatically deployed via gcode macros and can take advantage of your firmware’s probe pickup detection scheme to ensure probe pickup and docking.

Euclid Probe uses screw attached magnets for both mechanical coupling and for electrical contacts. It is simply the most reliable and secure method for attaching the magnets to the parts. The Z-Probe circuit is completed when the probe is attached to the dock.

Discussion and support is available as a subgroup to the CroXY Discord

CroXY Discord


Shipping November 14, 2021, the PCB board connector pinout has been updated to be SIG-GND-VCC to match most controller pinouts so that a premade straight-thru cable can be used instead of repinning a cable or making a custom cable.

In addition to the new pinout, we are including M2.5 size self tapping screws for plastic. This will make it easier to mount your Euclid to the provided mount designs with these screws, but still provide the option for tapping the PCB with M3 threads.

There is a new variant of Euclid that is 24V capable! This board will work with all controllers and voltages up to 24V, but specifically designed to support the 24V Z-probe option of the Fystec Spider line of controllers. The components have been to selected to handle the higher voltages.


In addition to updating the existing collection of probe mounts, we have been busy developing new mounts and docks for printers. We are pleased to announce that a native dock and mount have been developed for Voron Trident. See the Mounts page, Mount by Printer for the mount.

In collaboration with we now have a super-lightweight machined 7075 aircraft aluminum mount for RailCore printers! The mount weighs in at a mere 6.5 grams- that’s less than the combined weight of the nickel and penny in your pocket! Its the best, reliable probe solution for your RailCore 250, the 300 and the ZL/T series.

Update 12/6/2021: Check out the matching all metal dock that 713maker has produced! The dock is insulated so there is little risk of electronics damage should any part of the probe or magnets short against the dock or frame.
The specially made T-Nuts eliminate the need for printer disassembly to insert nuts in the extrusion channel in the case there are no spares. The hardware and fittings are the same 1515 used in the frame assembly, and have an ample range of adjustment to accommodate almost any combination of carriage plates, extruders, fan adapters and hot ends.


Euclid Probe YouTube Channel

Luke’s Lab Voron 2.4 Quad Gantry & Auto-Z Calibrate
slebed’s V-Core3 / RatRig Triple Screw Leveling
kageurufu’s Voron 2.4 Quad Gantry & Auto-Z Calibrate
Ermil’s Ender5 deploy and bedmesh

Build instructions are here

Available as Kits & Assembled Probes

Kits available with pre-populated SMT LED’s and resistors, ready for final thru-hole soldering assembly of switch and connection headers, polarized magnets and required hardware. Fully assembled & tested probes ready for deployment, cables and accessories too!
Buy Euclid Probe from
Lukes Lab Online


Printable mounts & docks for printers

We have probe dock and mount designs available for CroXY, Ender3/CR-10, Ender5, Railcore, Voron 2.4, Voron Trident, Eustathios, Wanhao i3.
Currently developing for Tiny-M & Voron Mini-AfterBurner

Example firmware configurations & macros

We have compiled configuration examples for Duet/RepRap Firmware, Klipper & Marlin and probe deploy/ retract macros

Probe Accuracy Testing

Little to no application data is available for the switches used in Euclid Probe. Therefore, the engineers and designers who created Euclid Probe embarked on their own testing campaign to qualify the switches and the other components used in construction. This includes mechanical accuracy testing of the individual switches, the entire probe assembly, and actual probe deployment and probe docking cycles on our test printers.

To date, over 100,00 probe deploy-probe-retract cycles have been performed. The only probe docking failures were due to operator error- not updating the probe Z-offset dimensions between sample changes.
The gathered data is compiled and analyzed to compare the performance between different switch manufactures and models. The overall results have been quite revealing- the usual suspects are not as accurate as they are purported to be, and the brands and models often dismissed are actually quite accurate.

Here is an example of a single switch’s probing results performed at room temperature.

Our inspiration

Troubled with inconsistent first layers, we sought to add a Z-probe to our printer with the hopes improving it. Our initial probe was a hand deployed endstop switch on a clamp. While it worked well, it was tedious to mount and un-mount. Then we tried a number of devices that showed promise and were more user friendly. Ultimately, nothing seemed to work as well matching the accuracy that the microswitch provided.