3" x 21" Sanding Belts, 12 PACK
3" x 21" Sanding Belts, 12 PACK
Available in stock (49985)
Most professional-grade portable belt sanders run a 3" x 21" belt: the Makita 9903, the DeWalt DW433 and DWP352VS, the Bosch 1274DVS and the Metabo HPT SB8V2 among them. It is also the size on the Craftsman CMEW213, Black+Decker DS321 Dragster and Bauer 57587 that fill out the job-site and home-shop market, and the metric 75 x 533 mm belt on the Bosch GBS 75 AE and Triton TA1200BS is the same belt.
We convert these on a poly-cotton cloth backing with heat-treated grain in Anaheim, California. Cloth A/O covers wood, paint, plastics and every finishing grit up to 800; Zirconia handles hardwood levelling and mild steel; Ceramic is for hardened and high-alloy steel under firm pressure. Twelve belts per pack, 24 through 800 grit.
- Fits the Makita 9903, DeWalt DW433 and DWP352VS, Bosch 1274DVS, Metabo HPT SB8V2 and more
- Same belt as the metric 75 x 533 mm size on Bosch GBS 75 AE and Triton TA1200BS
- Cloth A/O, Zirconia and Ceramic on tear-resistant poly-cotton cloth
- Widest grit spread in our portable range: 24 through 800 grit
- 12 belts per pack; free shipping on orders over $200
- Converted in Anaheim, California; custom lengths in about 3 days
Which 3" x 21" belt material should you choose?
Pick by the material you are sanding and by how much pressure you can honestly put on a hand-held sander.
- Cloth A/O (aluminum oxide): the default for wood and the only grain we stock in this size above the coarse grits. It levels oak and maple, flushes face frames, strips old finish and, in 320 through 800 grit, does the fine work that most belt sanders never see: denibbing between coats, flattening finish on a tabletop, and pre-polishing aluminum and brass. It works at the light pressure a portable sander applies.
- Zirconia: for faster removal on hardwood and for mild steel, weld beads and mill scale. It self-sharpens only when you lean on the sander, so it suits flat plank stock and plate rather than trim or veneer. Stocked 24 through 120 grit.
- Ceramic: a self-sharpening grain for hardened steel, stainless and high-alloy plate. On a portable sander it only pays off when you can bear down steadily on a flat steel surface; used lightly it glazes and heats the work. Fabrication and repair shops buy it; woodworkers should not.
The previous version of this page mentioned silicon carbide and grinding-aid zirconia. Neither is stocked in 3" x 21"; both can be quoted as a custom belt. Not every grain is stocked in every grit, so check the variant selector.
Grit guide for cabinet, door and furniture work
| Grit | Use it for | Notes |
|---|---|---|
| 24–40 | Stripping thick finish, heavy levelling, steel | Zirconia or ceramic; not for veneer |
| 60 | Flattening glue-ups, fitting doors, removing mill marks | Common first grit on solid wood |
| 80–100 | General surfacing, removing the 60 scratch | Where most time is spent |
| 120–150 | Pre-finish, plywood and veneer | Start here on veneer |
| 180–220 | Last belt before stain or clear | With the grain, light pressure |
| 320–400 | Between-coat scuffing, flattening finish | Cloth A/O only |
| 600–800 | Fine finishing, pre-polish on aluminum, brass, acrylic | Keep the sander moving |
Step one grade at a time. Skipping from 60 to 150 hides deep scratches until stain or a raking light finds them.
Which sanders take a 3" x 21" belt?
Verified against the manufacturer specification:
- Makita 9903
- DeWalt DW433 and DeWalt DWP352VS
- Bosch 1274DVS, and Bosch GBS 75 AE / PBS 75 A (75 x 533 mm)
- Metabo HPT SB8V2 / SB8V2M
- Craftsman CMEW213
- Black+Decker DS321 Dragster
- Bauer 57587 (Harbor Freight)
- Triton TA1200BS (76 x 533 mm)
Also listed on the previous version of this page as 3" x 21" machines (confirm the belt size in your manual before ordering): Porter-Cable 352VS, Genesis GBS321A variable speed, Craftsman 7.0 Amp, Warrior 56916 and Chicago Electric 6.5 Amp belt sanders.
Mounting: pull the tension lever to retract the front roller, slide the belt on so any direction arrow on the inside points the way the belt travels, lock the lever, then run the sander upside down and turn the tracking knob until the belt is centred on the platen and clear of the housing. Check the inside of the belt for a direction arrow before mounting.
How to get the most out of it
- Start the sander in the air, land it moving, lift it moving. Any pause with the belt on the wood leaves a dip.
- Work with the grain in overlapping passes the length of the board. On a glue-up, sand at a slight diagonal with the coarse grit to level the joints, then straight with the grain at the next grit to remove the diagonal scratch.
- Do not push. The weight of a 3" x 21" sander is the correct pressure for Cloth A/O. Extra force heats the belt, loads the grain and burns maple and cherry.
- Fitting doors and drawers: clamp the work, sand the edge with the platen square to the face, and check with a straightedge often; a belt sander removes a sixteenth faster than you expect.
- Veneer and plywood: Cloth A/O 120 or finer, one or two light passes, then stop.
- Keep the belt clean. Empty the dust bag, use extraction if the sander has a port, and press a crepe rubber belt eraser against the running belt when finish or resin packs the grain.
- Metal: zirconia or ceramic on steel with firm pressure; Cloth A/O with a grease stick on aluminum and brass so the belt does not load.
- Store belts hanging or loosely coiled away from damp; a belt that has taken a set thumps on the platen.
Use it for / don't use it for
Use it for
- Levelling glued-up panels, tabletops, benchtops and butcher block
- Fitting and flushing cabinet doors, drawer fronts, face frames and stair parts
- Stripping paint and old finish from solid wood doors, floors edges and furniture
- Between-coat scuffing and finish flattening with 320 through 800 grit Cloth A/O
- Dressing welds, removing mill scale and shaping steel plate (zirconia, ceramic)
- Cleaning and pre-polishing aluminum, brass and acrylic (fine Cloth A/O)
Don't use it for
- Final finish sanding that a random orbital should do; a belt leaves linear scratches
- Zirconia or ceramic on veneer, softwood or trim
- Cross-grain passes on any surface that will be stained
- Wet sanding on an electric portable sander
Specifications
| Size | 3" wide x 21" long (75 x 533 mm) |
|---|---|
| Abrasive grains | Cloth A/O (aluminum oxide), Zirconia, Ceramic |
| Backing | Poly-cotton cloth, heat-treated grain |
| Coat | Closed coat |
| Joint | Check the inside of the belt for a direction arrow before mounting |
| Grits offered | 24, 36, 40, 60, 80, 100, 120, 150, 180, 220, 320, 400, 600, 800 (zirconia 24–120) |
| Pack quantity | 12 belts |
| Wet or dry | Cloth backing tolerates both; run dry on electric portable sanders |
| Converted in | Anaheim, California |
| Custom sizes | Any width and length made to order in about 3 days |
Frequently asked questions
Do these fit the Makita 9903 and the DeWalt DW433?
Yes. The Makita 9903, DeWalt DW433, DeWalt DWP352VS, Bosch 1274DVS, Metabo HPT SB8V2, Craftsman CMEW213, Black+Decker DS321 and Bauer 57587 all take a 3" x 21" belt, and these belts are cut to that size. Mount with any direction arrow on the inside pointing the way the belt travels and set tracking before you start sanding.
Is a 75 x 533 mm belt the same as 3" x 21"?
Yes. 75 x 533 mm is the metric designation used by Bosch on the GBS 75 AE and PBS 75 A and by Triton on the TA1200BS (listed as 76 x 533 mm). Our 3" x 21" belt is the same size and tracks normally on those sanders.
What is an 800 grit belt sander belt actually used for?
Fine work that people do not expect from a belt sander: flattening a built-up finish on a tabletop before rubbing out, scuffing between coats over a large flat area, and pre-polishing aluminum, brass and acrylic. Use Cloth A/O, keep the sander moving and let its weight supply the pressure.
Which grit should I start with on a glued-up hardwood panel?
Start at 60 grit Cloth A/O to level the joints and remove dried glue, working at a slight diagonal to the grain. Follow with 80 and 120 straight along the grain to remove the diagonal scratch, then 150 or 180. If the joints are very uneven or the panel is thick oak or maple, 40 grit zirconia can take the first pass.
Can I use a 3" x 21" belt sander on steel?
Yes, with the right grain. Use Zirconia in 24 to 80 grit for mild steel, weld beads and mill scale, and lean on the sander so the grain keeps self-sharpening. Ceramic is for hardened steel and stainless under firm, steady pressure. Wear eye protection, keep sparks away from wood dust, and finish above 120 grit with Cloth A/O.
Why is the belt burning the wood?
Three usual causes: a dull or loaded belt, pushing down instead of letting the sander's weight work, or pausing in one spot. Maple and cherry burn first. Fit a fresh Cloth A/O belt, clean a loaded one with a belt eraser, keep the sander moving and let the grit do the cutting.
How many belts per pack, and what are the shipping and return terms?
Each pack holds 12 belts of one material and grit. Orders over $200 ship free, and unused belts in their original packaging can be returned within 30 days. For case quantities or a mixed-grit shop order, call 714-646-3299 or email sales@maverickabrasives.com.
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