Z Axis not cutting to depth

Battling yet again.

My cuts are not going to the correct depth. Checked the obvious things like a tight collet or any visible obstructions - but all clear. There is a horrible grinding noise every now and again on the Z axis that I cant seem to identify. The screen indicated it going to full depth, however it is only half way through the material.

Any suggestions?

I had an issue with X axis last week where it was not homing correctly and losing zero in between cuts. I replaced motor cable with the ONE spare in the box and it has been perfect since.

Which leads me to believe I may need to replace my Z motor cable - but I don’t have any more to test my theory. Any links to where these sort of cables can be purchased?

Thanks guys, but the $50 shipping on a $27 cable is where I’ve gotta draw the line.

Nothing special about them right? Are they normal stepper motor cables? I need to try find a replacement locally.

Non-Onefinity cables COULD potentially damage your controller permanently, voiding your warranty. Use at your own risk!

Hey Kyle,

Did you check if the Z ball screw coupler slips? See 4) in this document. I would check this before I order cables.

Also you could check your cables with a multimeter (move cable ends while multimeter probes inserted, to see if resistance increases).

Make your own stepper motor cables

for Buildbotics and Onefinity

If you want to make your own, here are the specifications, but it is required to own the appropriate crimp pliers (see below). Judge yourself what is more expensive.

Soldering them will lead to problems especially because the machine lacks strain relief.

For correct wiring of the stepper motor cables on the Onefinity CNC, see wiring diagram here. Here is the list of cable connectors used on the Onefinity:

Contacts and Crimp Tool:

Molex Male Crimp Terminal 0039000041:
39000041 Mini-Fit Male Crimp Terminal, Tin (Sn) over Copper (Cu) Plated Brass Contact, 18-24 AWG, Bag
Molex Female Crimp Terminal 0039000039:
39000039 Mini-Fit Female Crimp Terminal, Tin (Sn) over Copper (Cu) Plated Brass, 18-24 AWG, Bag

Amphenol Female Terminal 10127718-001LF:
Minitek® Pwr 3.0, Receptacle Terminal, 80μin Tin Overall (Contact area coated with lubricant, postplating).
Amphenol Male Terminal 10127719-001LF:
Minitek® Pwr 3.0, Plug Terminal, Phosphorus Bronze, 80μin Tin Overall Post plating.


Molex 4 Connector Housing 0039013046:
39013046 MiniFitJrPlg FreeHng /DH V2 Blk 4Ckt
Molex 4 Connector Housing 0039013045:
39013045 Mini-Fit Jr. Receptacle Housing, Dual Row, 4 Circuits, UL 94V-2, Black
Amphenol 4 Connector Housing 10127716-04LF
10127716-04LF Minitek® Pwr 3.0, Dual Row, Receptacle Housing, 4 Positions, Non GW Compatible Nylon66, Black Color.
Amphenol 4 Connector Housing 10127717-04LF
10127717-04LF Minitek® Pwr 3.0, Dual Row, Plug Housing, 4 Positions, GW Compatible Nylon66, Black Color.

:white_check_mark: Note: Generally I don’t buy the crimp pliers from the contact manufacturers because usually they’re too expensive and from my beginnings with electronics on, I know the excellent ‘Made in Germany’ Knipex pliers. So for the Molex contacts mentioned above, if you own a Knipex 97 43 200 A Crimp System Pliers for exchangeable crimping dies (version with case) (version without case),



Knipex 97 43 200 A – Crimping Pliers for interchangeable dies (version with case)Exchanging a die

you can simply buy the insert Knipex 97 49 26: Crimping die for connectors in the Mini-Fit™ series from Molex LLC (24–16 AWG model) and the Knipex 97 49 26 1: Locator for 97 49 26.



Image 3: Knipex 97 49 26 – Crimping die for connectors the Mini-Fit™ series from Molex LLC, (24–16 AWG model) – this one is needed to make cables for the Onefinity (use matching wire gauge!)

The matching Knipex 97 49 26 1: Locator for 97 49 26 ensures that the cable end is pushed in exactly as far as necessary for an optimum and safe crimping result.

If you own this pliers model for interchangeable dies, you have a universal tool holder for almost 1000 crimping applications with optimum transmission of force due to lever action for fatigue-reduced operation. So you could also buy e.g. a Crimping die for insulated terminals + plug connectors for the ring and spade connectors




Die for ring connectors

Die for wire ferrules

Use of optional locators

that are usually needed to connect your spindle and the other power cables to your VFD (or, if you prefer, the one for the heat shrinkable sleeve connectors), and you can also buy a Crimping die for insulated and non-insulated wire ferrules for your wire ferrules which are usually needed on the signal wires of your VFD and other components like relays.

You could for example use a selection of ring connectors and grounding wire to properly ground your Onefinity CNC (How to do this).

Anyway if you just buy the pliers and one die, usually it’s much less expensive than one original Molex or Amphenol or Phoenix crimp pliers, but you get still best industry quality with a Knipex.

Of course you can always get a no name crimp pliers for $25 everywhere, but in every case, please know that you won’t do yourself any good if you don’t

  • :warning: Always use a correctly matching crimping pliers / crimp die, that is made for the exact contact type you want to crimp, even when choosing a $25 model!

And please, also

  • :warning: Always make sure that the wire gauge you use matches the specification on the pliers/insert! Otherwise, especially at higher voltages, there may be serious electrical problems and hazards.