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Troubleshooting: Stuck or Stripped Zero Point Screw on the Z2

Updated

The zero point screw is the center screw under the wood accent on the front of your Z2. 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.

Why the screw gets tight

The screw can tighten up after shipping or after a big change in climate, like a move from Chicago weather to a dry or warm region. It is not a sign of a problem with your grinder, and it does not impact burr alignment.

If the screw is tight but not stripped

  1. Use the Wera 2.5mm hex screwdriver that came with your Z2. Its tip grips far better than a standard driver.
  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, wrap 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 adjustment assembly from the grinder so you are working on the knob off the body. The video shows how.
  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.

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 Z2 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. It does not need a torque spec, and overtightening makes the next zero reset harder. If you do have a torque driver, you can set it to 0.25-0.5 NM.

Once the new screw is in, reset your zero point. See Setting the Zero Point on Your Z2.

Still stuck?

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

Related

Setting the Zero Point on Your Z2 | Replacement Screws for Your Z2 | Troubleshooting: False Chirp and Zero Point Shift on the Z2

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