Original Makita part 231821-1 — Tension Spring 3. Designed to restore the return/tension action of the blade-guard assembly on compatible Makita circular saws, this small coiled spring slips into the guard mechanism to make the cover snap back smoothly after a cut.
Key details: the part is listed by Makita as "Tension Spring 3" (part no. 231821-1) and is supplied as the individual spring used in the blade-case / safety-cover assembly. Typical measured dimensions reported for this spring are a wire diameter of about 0.53 mm and a free length of approximately 77.5 mm (converted from the available specification). Use these measurements to confirm fit if you’re replacing a visibly worn or stretched spring.
Example models this part is used on (for reference): 5620D / 5620DWA, 5604R, 5630D, 5026D, 5036D, 5046D and the BSS610 / BSS611 series of Makita circular saws. Check your parts diagram for the blade-case/guard area to confirm the item number matches 231821-1 before installation.
Why this part matters: a tired or missing tension spring lets the guard hang or stick instead of returning, which interferes with safe, reliable cutting. Replacing the 231821-1 restores correct guard action and avoids erratic blade exposure.
This listing is for the original Makita tension spring, part number 231821-1 — a simple, low-cost replacement that fits into the guard assembly of the models listed above.
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