Rewind the original spool with bulk line
Use the LST300 fold, slot and adjacent-hole anchor, then wind neat layers only as far as the spool recesses.
Version 2.0.0. Required observations are marked *. Your answers stay in this browser.
1. Match the model and parts
Remove the battery. Find LST300 and the adjacent type number on the tool label. Compare the guard, cap, spool and assembly figures with the linked LST300 manual. Use ServiceNet for your exact type if they differ. LST300 is not a bump-feed head.
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.
Choose the versions you can confirm.
Compare versions →2. Prepare
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.
Consumables and fit
| Item | Specification & fit | Do not substitute |
|---|---|---|
| Bulk cutting line | 0.065 inch (1.65 mm) round nylon monofilament Intact original AF-100 spool with the slot, adjacent anchor hole, arrow and fill recesses in figs P–R | Serrated, square, heavier or metal line; different anchor geometryEnglish p10 Rewinding spool from bulk line; figs P–R |
| Factory-wound replacement spool | BLACK+DECKER AF-100; 0.065 inch (1.65 mm) round nylon monofilament Original LST300 automatic single-line head, after exact tool-type/manual match | Bump-feed or dual-line heads; metal, serrated or heavier line; unverified replacement headsEnglish p9 Cutting line / Line feeding; Replacement accessories |
3. Follow your checks
Match the model and preparation to start.
Read all possible routes
Is the battery removed, the trigger released and the cutting head stopped, with no battery damage, exposed wiring or faulty switch?
- Yes — Keep the battery removed for every hands-on step.
- No — 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 — Keep the battery removed. Save your preparation record and check the matching manual before continuing.
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 — Record the label type and matching manual reference in the first step.
- No — 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 — Keep the battery removed. Save your preparation record and check the matching manual before continuing.
Does the empty original spool match the slot, adjacent hole, direction arrow and recesses in figs P–R?
- Yes — Follow this exact anchor and fill limit.
- No — Use factory-wound AF-100 or obtain the correct type manual; do not use a generic spool anchor method.
- Not sure — Keep the battery removed. Save your preparation record and check the matching manual before continuing.
Is the bulk line round 0.065 inch (1.65 mm) nylon and the spool undamaged?
- Yes — Neat winding matters; factory-wound spools are recommended for best results.
- No — Obtain compatible line and an intact spool before winding.
- Not sure — Keep the battery removed. Save your preparation record and check the matching manual before continuing.
4. Follow and record
Complete the checks before recording physical work. Follow steps in order.
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.
Manual: Official model/type lookup instructions; type is beside or below the model numberRemove the empty spool and old line
Release the cap tabs and remove the cap and empty spool as in figs M–O. Remove all remaining old line from the spool. Inspect for cracks and locate the anchoring slot, adjacent hole, winding arrow and recesses.
Look for: The spool is empty and all four documented features are identified.
Manual: English p10 Rewinding spool from bulk line; figs P–RMake the specified fold
Fold the end of the compatible bulk line at approximately 3/4 inch (19 mm). Feed the line into one of the anchoring slots as fig P shows. Do not tie a knot or copy an anchor for another model.
Look for: The short folded end is about 19 mm and is aligned with the slot.
Manual: English p10 Rewinding spool from bulk line; figs P–RAnchor in the adjacent hole
Insert the 3/4 inch (19 mm) end into the hole beside that slot as fig Q shows. Draw the line tight against the spool. If your spool has no matching adjacent hole, stop and recheck compatibility.
Look for: The starting line sits tight against the spool in the slot-and-hole arrangement.
Manual: English p10 Rewinding spool from bulk line; figs P–RWind neatly to the recesses
Wind in the direction of the arrow actually marked on your spool. Keep the line in neat layers without crossing strands, as fig R shows. When the wound line reaches the recesses shown in fig Q, cut it. No fixed bulk length is substituted for this fill limit.
Look for: The layers do not cross and the fill stops at the spool recesses.
Manual: English p10 Rewinding spool from bulk line; figs P–RRefit with one eyelet exit
Thread the line through the housing eyelet and seat the spool on the boss with a slight turn. Allow approximately 5-3/8 inches (136 mm) outside the housing, snap both cap tabs into their slots and cut any excess nylon back to the guard cutter.
Look for: The spool is seated, the cap is secure and the line does not pass the cutter.
Manual: English pp9–10 Replacing the spool; figs M–ORecord the winding and follow-up
Record the line specification and whether the anchor, layers and fill limit match figs P–R. Complete after-care before use. Recurring tangles after correct winding are a reason to choose factory-wound AF-100 or seek support.
Look for: The record identifies this as a hand-wound spool and preserves any feed issue for later checks.
Manual: English p10 Rewinding spool from bulk line; figs P–R
5. Keep your result
Record what you observed. A completed checklist does not certify that equipment is repaired.
When to check again
Usable line is exhausted and an intact original spool will be reused
Inspect when the stated condition occurs. The manual gives no fixed day or month interval.
Manufacturer guidance · English p10 Rewinding spool from bulk line; figs P–RSources & fit
- BLACK+DECKER LST300 instruction manual (manufacturer document, retailer-hosted)English p10 Rewinding spool from bulk line; figs P–R · Checked 2026-10-13
- BLACK+DECKER: locate a manual using model and type numberOfficial model/type lookup instructions; type is beside or below the model number · Checked 2026-10-13
- BLACK+DECKER LST300 product and supportLST300 model identity; Automatic Feed Spool; Includes AF-100 · Checked 2026-10-13
Independent, AI-assisted guidance. No physical repair trial is claimed. Manufacturer instructions for your exact version take priority.