Inspect and secure the guard ID: lst300-guard-check 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: Phillips screwdriver only for the documented guard screw [ ] Material: Supplied undamaged type-matched guard and original screw, only if initial assembly is needed 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 Guard or mounting screw if a replacement is needed: Exact LST300 tool-type part identified by the manufacturer Fit: Supplied undamaged assembly, or a replacement confirmed through authorized service Do not substitute: Unverified guard, substitute screw, damaged tabs or housing threads Source: lst300-manual, English p8 Installing the guard; figs D–E 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: Is the supplied or installed guard intact and an exact match for figs D–E in your type manual? Yes -> check-2: Check its attachment without touching the sharp cutter. No -> service: Cracked, incorrect or damaged guards need the correct part and authorized service. Not sure -> prepared: Keep the battery removed. Save your preparation record and check the matching manual before continuing. check-2: Are the guard tabs, motor-housing ribs, locking slot and original screw intact? Yes -> steps: An undamaged supplied guard can be fitted as shown. No -> service: Do not compensate for damaged tabs or threads with a different screw, tape or force. 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. Inspect the installed guard Turn the stopped, battery-removed tool so the spool cap and guard can be seen. Look for splits, missing sections, bent mounting features and a loose screw. Keep clear of the line cutter. Look for: The guard has no damage and its mounting features can be identified. Source: lst300-manual, English p8 Installing the guard; figs D–E [ ] 3. Identify whether assembly is needed If the guard is already correctly secured, leave it in place and continue to the attachment check. For an undamaged supplied guard awaiting initial assembly, remove its supplied screw with a Phillips screwdriver. Look for: You are either checking the installed guard or fitting the supplied intact part; damaged mounting parts require service. Source: lst300-manual, English p8 Installing the guard; figs D–E [ ] 4. Fit the supplied guard if needed For initial assembly, turn the guard upside down and slide it fully onto the motor housing. Match guard tabs to the housing ribs in fig D and continue until the locking tab snaps into the housing slot. Do not force misaligned parts. Look for: The tabs engage the ribs and the locking tab occupies its slot. Source: lst300-manual, English p8 Installing the guard; figs D–E [ ] 5. Check the retaining screw For initial assembly, insert the supplied guard screw as fig E shows. For an installed guard, check that this screw is present and the guard is firmly retained. No torque value is provided in this task; damaged threads require service. Look for: The screw arrangement matches fig E and the guard stays firmly in place. Source: lst300-manual, English p8 Installing the guard; figs D–E [ ] 6. Check the cutter cover and record the result Only after a new guard is secured, remove the factory covering from the line cutter as the manual directs. Keep fingers away from the cutting edge. Record the mounting result; a missing, damaged or loose guard blocks operation. Look for: The mounted guard is secure; no factory cover remains when preparing for use. Source: lst300-manual, English p8 Installing the guard; figs D–E OBSERVATIONS Tool type exactly as printed on the label (required): ____________________ Exact-type manual reference or link that you matched (required): ____________________ Guard at the start (required): ____________________ Choices: Already installed / Supplied guard awaiting assembly Guard and supplied screw are firmly secured (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 [ ] Undamaged guard tabs, ribs, locking tab and screw are in the documented arrangement. [ ] The guard is firmly retained and the sharp cutter can be avoided during later checks. NEXT CARE Before use and after guard assembly or an impact Check guard condition before use. The manual does not give a screw torque or a replacement interval. Basis: manufacturer Source: lst300-manual, English p8 Installing the guard; figs D–E 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 p8 Installing the guard; figs D–E 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.