We offer knobs for some versions of the Zhumell Z12 primary and secondary, along with stronger springs to support the primary mirror. Our knobs will fit if your telescope matches our photos. Select the type of knobs/springs for your telescope from the list below. Price is for a complete set of knobs or springs.

A. Knobs for Zhumell Z12 f/5 Primary

Part: MLB12pri
Fits: Most Zhumell Z12 f/5 telescopes.

Primary collimation
  • Knobs: Black plastic, 30 mm (1-1/4”) diameter, 5-point fluted
  • Threads: Plated steel
Primary Lock
  • Knobs: Black plastic, 25 mm (1”) diameter, knurled
  • Threads: Stainless steel
  1. If your primary looks different from our photograph, or already has factory collimation knobs, these knobs will not fit.
  2. The telescope optical tube assembly will clear the rocker box with primary knobs installed.
  3. Primary adjustment knobs are slightly larger than shown in the photograph and do not have an orange insert.
  4. One of the primary mirror knobs may interfere with the cooling fan connector. The plug will fit properly between the knob flutes, so leave this one knob stationary and collimate using the remaining knobs. If desired, you can leave the factory collimation screw that is next to the fan connector in place.


B. Springs for Zhumell Z12 f/5 Primary

Part: CNspr
Fits: Zhumell Newtonian models (8”, 10”, 12”) except 16”

Primary mirror springs as supplied by the factory can sag from the weight of the mirror cell. Our stainless steel replacement springs are stronger and provide adequate support to maintain primary mirror collimation. We recommend that the mirror locking screws remain in place for additional control.

  1. These springs will fit if your primary mirror cell looks like the cell depicted in the photos above.
  2. $19.95


C. Knobs for Zhumell Z12 f/5 Secondary

Part: CNsec25 or CNsec35
Fits: Zhumell Z8, Z10, and Z12 telescopes

Knobs: Black plastic, 13 mm (1/2”) diameter
Threads: Stainless steel


  1. The factory collimation screw length, measured below the head, can be either 25 mm or 32-35 mm. Order knobs with the correct screw length for your application.

Screw length