Of course you can set the workpiece zero manually this way. You just got to be accurate in positioning it over the corner.
The XYZ touch plate is a very useful accessory (makes the procedure faster than manually setting workpiece zero). Note that this touch plate will not produce correct results when probing X and Y with a surfacing bit or a V-bit (see also here), in this case you use a rod, or and endmill inserted backwards as probe instead and reinstall the surfacing or v-bit to probe only Z separately then. Probing Z with the V-bit, on the other hand, will go more precisely and faster with the touch plate than setting zero manually.
See also
Support videos:
- How to use the XYZ Touch Probe
- How to Probe a V-Bit on the Onefinity CNC
- Manually Setting X,Y,Z Zero on the Onefinity CNC
- Onefinity Touch Probe Fine Tuning
Accessories