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Two stainless steel 40-tooth drive gears with 5mm bore and deep grooves for 1.75mm filament

Unique-Bargains

Unique-Bargains MK7/MK8 Drive Gear 40T 5mm Bore 2pcs

SKU CH-CFC2-R0JY2

Stainless-steel drive gear with 40 teeth and a 5 mm bore grips 1.75 mm filament for MK7 and MK8 3D printers

  • Deep grooves grip 1.75mm filament securely
  • Stainless steel construction resists wear during extrusion
  • 40 teeth provide consistent filament drive
  • 5mm bore fits MK7 and MK8 extruders
  • Two gears included for spare or dual setup

40-Tooth Stainless-Steel Drive Gear

This pair of 40-tooth stainless-steel gears fits MK7 and MK8 extruders and accepts 1.75 mm filament. Each gear has a 5 mm bore, 12 mm outer diameter and 12 mm height with an M3 thread for the set screw. The deep grooves provide a secure grip on the filament during printing. Supplied as a two-piece set for direct replacement or spare-part stock.

Replaces Worn Plastic or Damaged Metal Gears

Swapping to these steel gears is worthwhile when the original drive gear shows stripped teeth, rounded grooves or inconsistent extrusion. The harder material resists wear from abrasive filaments and maintains tooth profile longer than standard plastic gears. The upgrade makes sense for printers running high-volume jobs or filled materials that accelerate gear degradation.

Mounts Directly on 5 mm Motor Shafts

Installation requires a stepper motor with a 5 mm shaft and an M3 set screw to lock the gear in place. The 12 mm diameter keeps the gear compact inside typical extruder bodies, leaving room for the idler bearing and tension spring. No additional spacers or adapters are needed when the printer already uses MK7 or MK8 hardware.

Highlights

  • Deep grooves grip 1.75mm filament securely
  • Stainless steel construction resists wear during extrusion
  • 40 teeth provide consistent filament drive
  • 5mm bore fits MK7 and MK8 extruders
  • Two gears included for spare or dual setup

Specifications

BrandUnique Bargains

Questions about this item

Will the 12 mm outer diameter and 5 mm bore fit my MK7 or MK8 extruder?

The gear has a 12 mm outer diameter and a 5 mm bore, matching the standard MK7/MK8 extruder shaft size.

How do I install the gear on the motor shaft without stripping the M3 thread?

Slide the gear onto the 5 mm shaft, align the M3 grub screw with the flat on the motor shaft, and tighten gently — over-torquing the small M3 thread is the common mistake.

When should I replace these stainless-steel 40-tooth gears?

Replace them when the deep grooves that grip 1.75 mm filament show visible wear or the teeth no longer advance filament reliably.

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