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Troubleshooting: Stuck or Stripped Zero Point Screw on the Z1

Updated

The zero point screw is the blue center screw on the front knob of your Z1. You loosen it to reset the zero point. Sometimes it is much tighter than expected, and occasionally the head strips. Both are fixable at home, and you only need to work on the front knob.

When you might need this

Owners usually run into this while resetting the zero point after cleaning, a burr swap, or noticing the grind setting drift. The screw will not turn with normal force, or the driver starts slipping and rounding out the head.

If the screw is tight but not stripped

  1. Use a quality 2.5mm hex driver that fits the screw head snugly.
  2. Seat the tip fully in the screw head and press straight in, firmly, before you turn.
  3. Turn slowly while keeping that inward pressure.
  4. If it still slips, place a thin rubber band or a small piece of a rubber glove over the tip for extra grip and try again.

Stop if you feel the tip start to cam out of the screw. Forcing it is how the head strips.

If the screw head is stripped

  1. Try a 7/64 inch hex key. It is slightly larger than 2.5mm and often bites into a worn head.
  2. If that does not work, remove the front knob from the grinder so you are working on the knob off the body. Turn the knob fully coarse until it comes off.
  3. Use a small screw extractor to back the screw out. A Bosch #1 extractor bit works well. Follow the extraction steps in the video above.

Replacing the screw

The zero point screw is an M4 x 0.7 thread, 8mm long, flat head hex screw that takes a 2.5mm driver. A local hardware store usually has one. See Replacement Screws for Your Z1 for the exact part.

A small dab of anti-seize on the threads helps keep it from seizing again.

Tighten it only until it is snug and the dial sits firmly against the knob. Overtightening makes the next zero reset harder.

Putting the knob back on

  1. Thread the front knob back onto the grinder and make sure the adjustment mechanism is seated properly. See Opening, Cleaning, and Closing Your Z1.
  2. Reset your zero point. See Setting the Zero Point on Your Z1.

Still stuck?

If these steps do not work, please contact support at info@zerno.co.

Related

Setting the Zero Point on Your Z1 | Replacement Screws for Your Z1 | Troubleshooting: False Chirp and Zero Point Shift on the Z1