3-1/2" x 15-1/2" Surface Conditioning Belts (Non-Woven), 5 PACK
3-1/2" x 15-1/2" Surface Conditioning Belts (Non-Woven), 5 PACK
Available in stock (49989)
A rubber expanding drum on a bench grinder arbor or polishing lathe is the cheapest way to put a non-woven finish on curved parts, and 3-1/2" x 15-1/2" is the belt it takes. Slip the belt on, bring the drum up to speed, and the rubber swells to lock it in place; the wide face then blends, deburrs and satin-finishes castings, tube, brackets and formed sheet that would be awkward on a flat platen.
These surface conditioning belts are nylon web loaded with aluminum oxide grain on a reinforced scrim backing, sold five to a pack in one grade: Coarse, Medium, Very Fine or Ultra Fine. They run cool, resist loading on aluminum and stainless, and can be used wet or dry.
- Sized for 3-1/2" wide rubber expanding drums with a 15-1/2" circumference
- Wider face than a 3 x 10-11/16 drum belt for larger castings, tube and brackets
- Scrim backing does not stretch as the drum expands at speed
- Grades from 40–60 to 320–400 grit scratch, one grade per 5-pack
- Web conforms to fillets and radii without gouging or changing dimensions
- Free shipping on orders over $200; case pricing on request
Which grade should you run on an expanding drum?
A drum concentrates the contact into a narrow band and rotates faster at the rim than a belt sander platen moves, so every non-woven grade behaves a step more aggressive here. Choose accordingly.
- Coarse (40–60 grit scratch), brown: casting skin and parting lines on aluminum, bronze and iron castings, rust and scale on formed steel parts, stripping old coatings from brackets. Fast, and it will leave a groove if the part stops moving.
- Medium (80–120 grit scratch), maroon: the working grade for deburring machined and sheared edges, blending tube welds and preparing castings and brackets for paint or powder coat.
- Very Fine (180–240 grit scratch), blue: a directional satin on stainless fittings, tube bends, pump housings and food-equipment parts where the finish will be seen.
- Ultra Fine (320–400 grit scratch), grey: fine satin for decorative stainless, brass and aluminum, and the last step before buffing to a mirror.
If you run a drum next to a buffing wheel, the usual pair is Medium for cleanup and Ultra Fine straight into the buff.
Grade guide for castings, tube and formed parts
| Grade | Use it for | Notes |
|---|---|---|
| Coarse 40–60 | Casting skin, scale, old coatings | Keep the part moving |
| Medium 80–120 | Deburring, weld blending, paint prep | Working grade |
| Very Fine 180–240 | Satin on stainless fittings and tube | After 180–220 coated |
| Ultra Fine 320–400 | Fine satin, pre-buff on brass and stainless | Lightest pressure |
Where the part carries a coarse scratch from grinding, run a coated drum belt of the matching grit first; non-woven refines a finish, it does not remove one.
What does a 3-1/2 x 15-1/2 belt fit?
- Rubber expanding drums 3-1/2" wide with a 15-1/2" belt circumference, mounted on a bench grinder arbor, buffing lathe or dedicated drum sander. Our previous page for this belt described it as a common expanding drum size, and that remains its main use.
- Pneumatic and electric drum sanders that carry an expander drum of this size for foundry, tube and fabrication finishing.
Confirm the drum's width and belt circumference before ordering; expanding drums come in several diameters and there is no tension adjustment to absorb a mismatch. Mounting: with the machine stopped, slide the belt over the drum and center it on the face. It will feel slightly loose. Start the machine and let it reach full speed so the rubber expands and grips before the part touches the belt. Non-woven belts have no direction arrow. The coated version of this same size is our 3-1/2" x 15-1/2" drum sanding belt, which pairs with these for a grind-then-condition sequence on one drum.
How to get the most out of them
- Let the drum expand before contact. Touching the part to a belt that is not yet gripped spins the belt on the rubber and glazes the inside of the web.
- Present the part lightly and keep it moving. A drum already concentrates pressure into a narrow strip. Roll the part across the face in a steady sweep; stopping leaves a bright band and can round an edge you wanted crisp.
- Use the whole width. Work across the full 3-1/2" face so the belt wears evenly instead of developing a trench in the middle.
- Follow a matching coated grit. Medium after a 120 grit coated drum belt, Very Fine after 180–220. A grade that is too fine for the incoming scratch just polishes the tops of the lines.
- Lubricate on aluminum, brass and titanium. The belt is waterproof; a light mist of water or cutting fluid stops soft metals smearing into the web and keeps titanium from discoloring.
- Clean and store. Blow the web out with compressed air, keep spares flat or hanging, and dry a wet belt before it goes back in the pack. A belt eraser at light pressure lifts packed swarf.
Use it for / don't use it for
Use it for
- Cleaning and blending aluminum, bronze and iron castings on fillets and parting lines
- Satin finishing stainless fittings, tube bends, pump and valve bodies
- Deburring machined, sheared and laser-cut parts without changing dimensions
- Removing rust, scale, heat tint and oxidation from formed and curved parts
- Preparing brackets and hardware for paint, powder coat or plating
- Pre-buff satin on brass, copper and aluminum decorative parts
Don't use it for
- Stock removal or grinding welds flush; use the coated drum belt first
- Large flat panels, where a platen belt gives a straighter, more even grain
- Expanding drums of any other size
- A mirror finish on its own; follow Ultra Fine with a buffing wheel and compound
Specifications
| Size | 3-1/2" x 15-1/2" |
|---|---|
| Abrasive | Aluminum oxide in a non-woven nylon web |
| Backing | Reinforced scrim, stretch-resistant |
| Grades offered | Coarse (40-60), Medium (80-120), Very Fine (180-240), Ultra Fine (320-400) |
| Color code | Brown / maroon / blue / grey |
| Joint | Bi-directional, no arrow |
| Pack quantity | 5 belts, one grade per pack |
| Wet or dry | Both |
| Fits | 3-1/2" wide rubber expanding drums, 15-1/2" circumference |
| Converted in | Anaheim, California |
| Custom sizes | Other drum sizes made to order in about 3 days |
Frequently asked questions
What kind of machine uses a 3-1/2 x 15-1/2 surface conditioning belt?
A 3-1/2" x 15-1/2" belt fits rubber expanding drums of that width and circumference, mounted on a bench grinder arbor, a buffing lathe or a drum sander. The drum expands as it spins and grips the belt from inside, so the belt can be swapped in seconds. It is used to blend, deburr and satin-finish castings, tube and formed parts.
Can I use the same drum for the coated belt and the non-woven belt?
Yes. The coated 3-1/2" x 15-1/2" drum sanding belt and this non-woven belt fit the same expanding drum, so you can grind or remove scale with the coated belt, stop the machine, swap to a Medium or Very Fine non-woven belt and finish on the same setup. Match the non-woven grade to the coated grit you finished with.
Why does the belt feel loose on the drum when I install it?
That is normal. An expanding drum is undersize at rest and grows in diameter at speed, so a 3-1/2 x 15-1/2 belt should slide on without force and feel slightly loose. Start the machine and let it reach full speed before the part touches the belt; the rubber will have expanded and locked the belt in place by then.
Which grade should I use to clean up aluminum castings?
Start with Coarse (brown) to take off casting skin, parting-line flash and heavy oxide, then Medium (maroon) to leave an even matte ready for paint or powder coat. Keep pressure light and keep the casting moving across the drum face. A mist of water or light lubricant keeps aluminum from smearing into the web.
Will non-woven belts round over the edges of my parts?
They can if you dwell, especially the Coarse grade on a drum, because the web is conformable and the drum concentrates pressure. Keep the part moving, present edges at a shallow angle rather than square on, and use Medium or finer for parts where a crisp edge matters. Used that way, the belt deburrs without visibly changing the edge.
How many belts are in the pack and can I buy in bulk?
Each pack has five 3-1/2" x 15-1/2" belts of one grade: Coarse, Medium, Very Fine or Ultra Fine. Foundries and fabrication shops that run drums all day can ask about case quantities and bulk pricing by calling 714-646-3299 or emailing sales@maverickabrasives.com. Orders over $200 ship free.
Related products and guides
Couldn't load pickup availability
Get $20 off when you spend $1,000 or more! Learn more
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
