CNC Touch Probes & Tool Setters: BitZero, AutoZero and Z Probes
A touch probe can locate the workpiece; a tool setter can measure cutter length. Use the chooser below to separate those jobs and follow manufacturer-documented compatibility instead of assuming every probe works with every controller.
A touch plate or work probe establishes a work reference; a tool-length setter measures the installed cutter. Products such as BitZero, BitSetter, Z probes and tool setters may look related, but they solve different setup problems.
Probe and tool-setter chooser
Choose what you are trying to automate and the machine ecosystem. The result points to manufacturer-documented paths where we have them.
Three accessories that are often confused
| Accessory | What it measures | Typical use |
|---|---|---|
| XYZ touch plate / work probe | Workpiece origin | Find X, Y and/or Z zero before machining. |
| Z puck / Z probe | Workpiece surface height | Automate Z-zero without finding X/Y. |
| Tool setter / tool-length sensor | Installed cutter length or offset | Maintain Z reference when changing tools or operating an ATC workflow. |
A product can combine some functions, but do not assume it does all three because the word “probe” appears in the listing.
Shapeoko: BitZero and BitSetter are deliberately separate
Carbide 3D currently describes BitZero V2 as the accessory for locating X, Y and Z zero. It uses a low-profile body, magnetic ground and a bore for X/Y probing; Carbide states that the current adapter cable supports all Shapeoko machines with Carbide Motion 5.14 or newer.
BitSetter serves a different workflow. It measures the cutter length and lets Carbide Motion preserve Z reference across tool changes. Carbide's own FAQ explicitly says BitSetter does not replace the touch probe.
That distinction matters for search intent: someone looking for “BitZero” usually wants work-zero probing; someone looking for a tool setter may actually need BitSetter.
Sienci: AutoZero is an XYZ work-probing system
Sienci's AutoZero Touch Plate is designed for X/Y/Z zero-setting and its current documentation says all Sienci Labs machines are compatible. gSender contains built-in AutoZero support, and Sienci also documents standard-block and Z-puck workflows for other touch plates.
For a LongMill or AltMill owner, that is a much stronger evidence path than buying a generic block because the plate, controller and sender workflow are documented together.
Genmitsu: exact model support matters
SainSmart's current wireless Z-axis tool setter names the 3020-PRO MAX V2, 3020-PRO Ultra, 4040 Reno, 4040-PRO and 4040-PRO MAX for its plug-in cable. It also includes a separate open 3-pin connection for custom GRBL/Mach3 installations, but SainSmart instructs users to verify pinout and voltage.
A broad “GRBL-compatible” description is therefore not enough to confirm fit with every Genmitsu or desktop CNC. The electrical interface, probe logic and sender settings still need to match the exact controller.
Before connecting a probe, verify the whole signal path
A probe is not compatible merely because its plug looks familiar. Check the exact controller's probe input, the accessory's supply requirements if it is powered, normally-open or normally-closed logic, connector pinout and the control software's probing routine. For a touch plate, the software also needs the correct plate dimensions or thickness so the calculated work zero is meaningful.
This is especially important with “universal” accessories. SainSmart's current Genmitsu tool setter illustrates the difference between an exact plug-in cable for named models and a separate open-header path intended for custom installations. The second path creates flexibility, but it also puts the burden on the installer to verify the electrical and software details.
Decide whether you need faster setup or automatic tool changes
A hobbyist running one cutter for an entire sign may get most of the benefit from a simple Z plate or XYZ work probe. A repeat-production workflow with several cutters benefits more from consistent tool-length measurement after each change. Those are different reasons to buy hardware, and the more automated workflow may also depend on the controller and sender maintaining the correct offsets.
Manual zero-setting remains a valid workflow on many CNC routers. A probe is most valuable when it reduces repeated setup steps, helps establish the same reference consistently, or integrates with a documented tool-change process. It should not be presented as a prerequisite for accurate machining by itself.
Probe repeatability cannot fix a bad mechanical setup
A touch probe can make origin-setting faster and more repeatable, but it does not flatten a warped spoilboard, tram a spindle, tighten a loose fixture or correct an inaccurate tool diameter. Treat probing as one reference step inside the whole setup.
If the table itself needs attention, use the Spoilboard & Surfacing guide. If the workpiece can move during probing or cutting, use the Workholding selector.
Browse generic CNC touch probes and tool setters
Generic probe hardware can be useful on controller families that publish a compatible probe input, but verify voltage, normally-open/normally-closed logic, connector pinout, plate thickness and sender configuration before connecting it.
Current manufacturer sources
- Carbide 3D BitZero V2 ↗Current purpose, compatibility and BitZero-vs-BitSetter distinction.
- Carbide 3D BitSetter ↗Current tool-length/offset workflow and supported Shapeoko families.
- Sienci AutoZero documentation ↗Current all-Sienci compatibility and gSender setup.
- Genmitsu wireless Z tool setter ↗Exact named models plus the separate custom GRBL/Mach3 wiring path.
Frequently asked questions
What is the difference between a CNC touch probe and a tool setter?
A touch plate or work probe establishes the workpiece zero or origin. A tool setter measures tool length or tool offset, especially after a tool change. Some products are marketed loosely as probes, so identify the job before choosing the hardware.
What is BitZero used for?
Carbide 3D's BitZero V2 is a Shapeoko accessory for finding X, Y and Z zero on the workpiece. Carbide explicitly distinguishes it from BitSetter, which measures cutter length during tool changes.
Does BitZero work on all Shapeoko machines?
Carbide 3D currently states that BitZero V2 ships with an adapter cable, requires Carbide Motion 5.14 or later and is compatible with all Shapeoko machines.
What is Sienci AutoZero used for?
AutoZero is Sienci's X/Y/Z touch plate. Sienci's current resources state that all Sienci Labs machines are compatible with it and that gSender includes the probing workflow.
Can a generic Z probe work on any GRBL CNC router?
Not automatically. The probe input type, logic, voltage, connector, sender settings and probe thickness all need to match the controller. A universal-looking connector is not proof of electrical or software compatibility.
Do I need to buy a touch probe to use a CNC router?
No. Work zero can be established manually on many CNC routers. A probe mainly improves convenience and repeatability. Tool setters are particularly useful when a workflow includes multiple tool changes.