The 9403 is a continuous-belt sander. Its abrasive dimensions and belt surface speed cannot be compared directly with a round sander’s OPM.
Belt dimensions
The US page specifies 4 × 24 inches; the indexed manual gives 100 × 610 mm. Do not use the narrower 9921 row in the shared manual.
Belt speed
The US page gives 1,640 ft/min; the manual also expresses belt speed as 500 m/min. These are surface-travel units, not OPM.
Direction and static fitting
Indexed instructions require power disconnected for belt installation and matching the belt arrow with the tool direction mark.
Tracking boundary
The manual describes tracking with the tool running. This library supplies no generic live-adjustment sequence; drifting or damaged belts require stopping and appropriate assessment.
Cord and handling
The product places the cord above the handle. Indexed operating instructions require a two-handed hold and warn against excess pressure.
Weight discrepancy
The current product page lists 12.6 lb, while the indexed manual lists 13.0 lb. This discrepancy is not resolved into a handling ranking.
Check before you follow
Identity & documentation.
- Brand
- Makita
- Model
- 9403
- Tool type
- Belt sander
- Market
- United States
- Manual revision used
- Printed revision not verified.
- Evidence level
- Manufacturer documentation; no physical testing
A source check date records this research pass. It does not confirm that a manual is the newest possible revision, a tool is still in production, or a particular unit matches these documents.
The US-linked 9403_IM.pdf covers 9403 and 9921. The printed revision is unverified; keep model rows separate.
Manuals & service references
Identify the right document.
These are document reference records, not downloadable manuals. Original manufacturer files are not provided here. Match the exact model and revision before use. A parts reference does not authorize internal repair.
Operator manualPDF
9403 / 9921 US-linked belt-sander manual
Indexed model identity; direct file unverified
Official US-linked manual identified through indexed text; complete PDF retrieval failed and exact regional applicability remains limited.
Document revision: Printed revision not verified.
9403 / 9921 US-linked belt-sander manual
Original document languages: en
Official indexed text checked; direct download unverified
Keep the limits in view.
- Full linked PDF retrieval failed; only official indexed text was inspected.
- No stationary mounting configuration or arbitrary vacuum adapter is verified here.
Read the instructions for the tool and any applicable battery or charger together. Routine owner care stays outside the housing; internal service belongs with the manufacturer or an authorized service provider.
Keep reading
Makita: explore this brand’s tool references
Guides for this model
Explore controls, comparisons and documentation for this exact model.
- Makita disc or belt
These are not simply light and heavy substitutes. BO5041 organizes work around disc refinement and variable speed; 9403 around continuous-belt removal. Identify the needed stage first.
- Choose the right sander type
Choose a sander for tabletops, cabinet corners or thin veneer, with practical differences in reach, abrasives and dust collection.
- Read sander speed correctly
12,000 OPM and 1,640 ft/min cannot share a meaningful bigger-is-faster ranking. Identify the motion before using the number to choose a tool.
- Check abrasive fit
Diameter alone is not enough. Format, attachment, specified abrasive size, extraction openings and exact tool identity belong on the same shopping list.
- Belt tracking boundaries
Check belt installation before correcting its travel. Fitting is done unplugged; tracking requires observing a running belt. They are different operations.
- Select the 9403 belt
Select by both dimensions, then material, condition and direction. A four-inch label alone is not enough.
- 9403 clamps and cord path
Check the full envelope of clamps, bag, cord and both hands on a wide board before using the 9403 contact sequence.
- Choose the removal stage
Coarse preparation of a known solid-wood panel is not the same task as removing the previous grit scratches. Define removal and geometry first; not every job needs belt sanding before a disc.
- Belt-sander cross-grain scratches
Identify grain and scratch direction on visible solid wood, establish a with-grain sample and do not import floor-drum sanding angles.
- Prevent unintended belt-sanded roundovers
Record original geometry and fit, plan fully supported travel and compare against the original edge after stopping.
- Handheld-use boundary
Clamping the tool frees your hands but changes work support, abrasive exposure and stopping control at once. A lock-on switch does not supply those missing conditions.
- Raised-joint decisions
A raised seam does not automatically mean the higher board needs sanding thinner. Sidelight and a straightedge help separate dried glue from a genuine step before you create a hollow.
The reading behind this guide
Source records describe the evidence used for this guide. Original manufacturer files and external videos are not provided here.
Sources & references.
Manufacturer documents and public safety references are the starting point. Check each source’s scope and confirm the exact model, market, and revision for your tool.
- Makita USA: 9403 US product listing 9403
Checked
Official indexed text checked; direct download unverified
US listing; stock, price and latest-generation status are not established.
- Makita: 9403 / 9921 US-linked belt-sander manual 9403_IM.pdf; cover models 9403 / 9921
Revision Printed revision not verified. · Checked · Pages Indexed pages 1–2, 7–9
Official indexed text checked; direct download unverified
US-linked indexed manual covers both 9403 and 9921. Do not transfer the narrower 9921 belt size. Printed revision not verified.