This my new extruder for MK8 Gear. Gear have OD 9mm against OD 12mm in MK7, that use in Replicator, FF, CTC. Its needing for new Alu Cooling Block (Bar) that hold hotends and motors. Because it will be 37mm between holes/nozzles against 33mm in original or 34mm for Flashforge 9mm Gear has strong extrusion in theory (34% power up).

v 4.0 Redesign mount block, like FlashForge.

v 2.0 Add bearning for imbus screw

Parts for assembly : 2x imbus scew 3x16 (or 3x14) 2x flat-head screw 3x6 2x MK8 Gear (OD 9mm!) 1x new Aluminium Bar (Block) with 37mm between nozzle.

** EXTRUDER IN PROCESS. **

bearing Used for this extruder is 623Z, 623ZZ (ID:3OD:10TH:4)

https://ru.aliexpress.com/item/623Z-ABEC-5-Chrome-steel-bearings-10pcs-metal-Sealed-Miniature-Mini-Bearing-free-shipping-623/32695350387.html

Setting for MK8 gear: From reprap: Real-life measured data (tested with 1.7mm filament):

Effective diameter: 6.7mm Effective circumference : 21mm Steps per mm: 152 approx. - tested with direct drive, 200 steps/rev and 1/16th. microstepping: 200 * 16 / 21 ~= 152

from other sources: E steps for that should be around 145.xx

Extruders benchmark: https://airtripper.com/1676/3d-printer-extruder-filament-drive-gear-review-benchmark/

When are you buy MK8 Gear with Ali, see that "precision".