Replace the cutting-line spool ID: lst300-spool-replace Version: 2.0.0 Model: BLACK+DECKER LST300 · US · AF-100 Region: US Parts: Automatic-feed head with AF-100 spool; match model and tool type to manual Not covered: LST420 / LSTE525; GH corded models; Dual-line heads; Metal line or blades; Nonmatching tool type or modified head; Unknown tool type or missing exact-type manual; Bump-feed conversion MATCH YOUR VERSION Model and tool type: LST300 and the exact type on my label match my manufacturer manual and figures Remove the battery before finding the label. Use the manufacturer model-and-type lookup; this site does not infer a type number from LST300 alone. Cutting head: Original AF-100 automatic-feed single-line head Do not substitute a bump-feed procedure, dual-line spool or metal cutting attachment. PREPARE [ ] Release the trigger, let the head stop, engage the lock-off and remove the battery. Leave it removed throughout hands-on care. Keep fingers away from the sharp cutter on the guard. [ ] Read LST300 and the tool type from the label. Open the official model/type lookup and compare its manual and parts figures with your actual guard, single-line head and AF-100 spool. A readable model name alone does not establish the type. If the exact type manual cannot be obtained, or any figure differs, save a preparation record and stop. [ ] Tool: Good lighting [ ] Tool: Scissors for nylon line only [ ] Material: Compatible factory-wound BLACK+DECKER AF-100 spool STOP Keep the battery removed if the exact type/manual match is unknown or parts differ from the figures. Stop for a damaged battery, exposed wiring, a faulty switch, cracked guard, broken spool/hub, damaged cap tabs or housing slots. Use an authorized service center. Never open the battery, motor housing or charger. CONSUMABLE FIT Factory-wound replacement spool: BLACK+DECKER AF-100; 0.065 inch (1.65 mm) round nylon monofilament Fit: Original LST300 automatic single-line head, after exact tool-type/manual match Do not substitute: Bump-feed or dual-line heads; metal, serrated or heavier line; unverified replacement heads Source: lst300-manual, English p9 Cutting line / Line feeding; Replacement accessories Replacement spool cap: BLACK+DECKER RC-100, confirmed against the exact tool-type parts list Fit: Original compatible AF-100 housing with undamaged slots Do not substitute: Damaged housing; caps with different tabs; forcing an apparently similar part Source: lst300-manual, English p9 Cutting line / Line feeding; Replacement accessories CHECK ROUTE safety: Is the battery removed, the trigger released and the cutting head stopped, with no battery damage, exposed wiring or faulty switch? Yes -> compatibility: Keep the battery removed for every hands-on step. No -> service: Stop using the tool for electrical, battery or switch damage. If you have only omitted battery removal, make the tool safe before restarting. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. compatibility: Have you matched the label LST300 AND its exact tool type to the official lookup manual and its figures, with the original AF-100 automatic single-line head? Yes -> check-1: Record the label type and matching manual reference in the first step. No -> prepared: An unknown type, unavailable type manual, different figures, bump-feed head or dual-line conversion blocks this procedure. Use manufacturer support to identify the correct instructions. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. check-1: Does the replacement package identify AF-100 and 0.065 inch round nylon line? Yes -> check-2: Use the factory-wound spool after confirming the type match. No -> prepared: Use Check the replacement line specification before opening the head. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. check-2: Are the guard, cap tabs, housing slots and visible feed lever intact? Yes -> steps: Work with the removed battery beside the tool. No -> service: A replacement spool cannot repair damaged retaining parts. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. CARE STEPS (only when the route reaches steps) [ ] 1. Record the exact tool and make it safe Release the trigger, let the head stop, engage the lock-off and remove the battery. Leave it removed throughout hands-on care. Keep fingers away from the sharp cutter on the guard. Read LST300 and the tool type from the label. Open the official model/type lookup and compare its manual and parts figures with your actual guard, single-line head and AF-100 spool. A readable model name alone does not establish the type. If the exact type manual cannot be obtained, or any figure differs, save a preparation record and stop. Look for: The battery is physically separate from the tool; your label type and matching manual reference are written below. Source: bd-manual-help, Official model/type lookup instructions; type is beside or below the model number [ ] 2. Release the cap and lift out the spool Squeeze both cap tabs and lift the cap from the housing. Hold the housing with one hand and draw the old spool out with the other. Keep the parts together; avoid pulling on the feed lever. Look for: The cap and spool separate without a pry tool; both tabs remain intact. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O [ ] 3. Clear and check the empty housing Remove loose grass and dirt from the spool and housing. Find the central boss and the lever shown in fig N. If the lever has moved, refit it only when its pictured position is clear; otherwise stop for help. Look for: The boss is clear and the lever matches fig N without being forced. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O [ ] 4. Thread the one line exit Release the new spool line from its transport hold and pass that end through the housing eyelet shown in fig O. Keep the line outside the rim where it exits; do not trap it beneath the spool. Look for: One nylon line passes through the eyelet, with no second outlet or doubled strand. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O [ ] 5. Seat the spool on its boss Push the spool onto the central boss and turn it slightly until it settles. Arrange approximately 5-3/8 inches (136 mm) of line outside the housing. Keep the lever in its documented position. Look for: The spool sits down in the housing; it does not rock above its seat. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O [ ] 6. Latch the cap and limit the line Align both cap tabs with the housing slots and push until securely snapped in. Check that both sides hold. If nylon extends past the guard cutter, use scissors to shorten it so it only reaches the blade; keep hands away from the blade. Look for: Both tabs retain the cap and no line is trapped under its rim or extends beyond the cutter. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O [ ] 7. Record the refit before returning to use Keep the battery out while you record the spool identity and cap result. Finish Verify the trimmer after maintenance before any normal-use test. A cap that lifts or a spool that will not settle needs the cap-latch check or service. Look for: The record describes the fitted part and a secure cap; operating performance is still untested. Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O OBSERVATIONS Tool type exactly as printed on the label (required): ____________________ Exact-type manual reference or link that you matched (required): ____________________ Spool marking checked (required): ____________________ Cap after refitting (required): ____________________ Choices: Both tabs hold / Loose, damaged or uncertain [service required] Result of this task (required): ____________________ Choices: Checks passed; ready for the stated next step / More preparation or a linked task is needed [further care/preparation needed] / Leave unused and contact service [service required] RESULT CHECKS [ ] AF-100 is seated on the boss and its single line exits through the eyelet. [ ] Both cap tabs hold; the guard is secure and the line reaches no farther than the cutter. NEXT CARE Spool empty or insufficient usable line remains Inspect when the stated condition occurs. The manual gives no fixed day or month interval. Basis: manufacturer Source: lst300-manual, English pp9–10 Replacing the spool; figs M–O Record preparation, maintenance readiness, problem located or service needed. This is not proof of a physical repair. SOURCES BLACK+DECKER LST300 instruction manual (manufacturer document, retailer-hosted) https://pdf.lowes.com/productdocuments/1935f26b-7448-4c95-b467-a223bb73d80f/63056925.pdf English pp9–10 Replacing the spool; figs M–O Checked: 2026-10-13 Manufacturer copyright, hosted by Lowe’s. Facts paraphrased; no diagrams or manual redistributed. BLACK+DECKER: locate a manual using model and type number https://support.blackanddecker.com/hc/en-us/articles/360012700118-How-can-I-get-a-parts-list-or-manual-for-my-tool Official model/type lookup instructions; type is beside or below the model number Checked: 2026-10-13 Linked only. BLACK+DECKER LST300 product and support https://www.blackanddecker.com/products/lst300 LST300 model identity; Automatic Feed Spool; Includes AF-100 Checked: 2026-10-13 Linked only; no product photos reused.