Step 08.12 — Seat the first MR85 in the motor plate¶
Step 12 of 65 · Chapter 08 — Toolhead: Stealthburner, Clockwork 2, Revo HF, Nitehawk-SB V2
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Parts:
- the motor plate with its inserts · already on the bench
- MR85 bearing ×1 · Motion box
Do: Press the MR85 fully into its plastic pocket, even pressure on the outer ring only. Never push on the inner ring. If it needs real force the part is over-extruded: check the print rather than hammering it.
Check
The bearing face is flush with the pocket floor and spins freely.
What you're looking at
An MR85 is a small ball bearing, 5 mm bore and 8 mm outside; two of them carry the extruder's drive shaft, one in each printed half. Pressing on the inner ring drives load through the balls and dents the races.
Source: SB manual p.19