Original Makita brush holder — part no. 643943-9 — designed to replace the motor brush holder assembly in compatible Makita cordless circular saws and similar compact tools. It’s the plastic/metal holder that secures the carbon brush and the metal contact/receptacle so the brush maintains reliable electrical contact with the commutator during operation. The parts diagram for the tool shows this item paired with Makita carbon brushes CB‑429 and mounted using a P.H. screw M5 × 40 (referenced in the same assembly), so it’s the correct fit where those components are specified.
Key details
- Part: Makita brush holder, 643943-9 (original Makita part).
- Function: Holds the carbon brush and provides the motor contact/receptacle; intended to restore proper brush seating and electrical contact.
- Associated brush: typically used with carbon brush CB‑429 as shown in the Makita parts diagram.
- Mounting: aligns in the motor housing and secures with a pan-head P.H. screw M5 × 40 per the exploded parts list.
Common-fit models (examples)
- Makita 5621RD (cordless circular saw).
- Makita 5036D / 5036DWB series (corded circular saw variants listed with this brush holder).
- Makita 5046DWB / 5046DWD (cordless circular saw parts diagram lists 643943-9).
Why this part matters
- Worn or loose brush holders cause poor brush contact, sparking, reduced motor power and intermittent operation; replacing the holder restores correct brush alignment and helps the motor run smoothly.
If you’re repairing a saw that uses CB‑429 brushes or you see 643943‑9 listed on your tool’s exploded parts diagram, this original Makita brush holder is the direct replacement to get the motor assembly back to spec.
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