Rotary Tool Attachments Guide: Every Bit Type Explained

Category 1: Cutting Attachments

Fiberglass-Reinforced Cutting Wheels

What they look like: Thin, rigid brown or black discs, about 1-1.5 inches in diameter.

Best for: Cutting metal — nails, screws, bolts, thin sheet metal, and small pipes. The fiberglass reinforcement prevents shattering, unlike the brittle emery wheels included in cheap kits.

Speed: 25,000-35,000 RPM. High speed required.

Safety note: Always wear eye protection. Never use a damaged or bent wheel — it will fly apart at speed.

Heavy-Duty Cut-Off Wheels

Best for: Thicker metal and harder materials. These are slightly thicker than standard cutting wheels and last longer on demanding cuts.

Diamond Cutting Wheels

Best for: Tile, stone, glass, ceramic. Diamond grit bonded to a metal wheel cuts hard, brittle materials that would destroy standard abrasive wheels. Use with water for tile to control dust.

Spiral Saw Blades / Wood Cutting Wheels

Best for: Wood, plastic, soft metals in straight or curved cuts. The toothed edge acts like a miniature circular saw blade.

Category 2: Sanding and Shaping Attachments

Sanding Drums

What they look like: Small cylinders with sandpaper sleeves, typically in 1/4, 3/8, and 1/2-inch diameters.

Best for: Shaping wood, smoothing edges, contouring curves. The drum's small diameter reaches inside curves that a palm sander cannot touch.

Grits: 60-80 (coarse shaping), 120 (general smoothing), 240 (fine finish).

Speed: 10,000-20,000 RPM for wood, slower for plastic to prevent melting.

Flap Wheels / Sanding Discs

Best for: Flatter surfaces. The larger contact area levels material faster than a drum. Good for removing paint or smoothing flat stock.

Grinding Stones (Aluminum Oxide)

What they look like: Tapered or cylindrical gray/pink stones in various shapes — cone, cylinder, ball, wheel.

Best for: Grinding metal, removing burrs, sharpening tools, shaping hardened steel. Grinding stones remove material aggressively.

Speed: 15,000-25,000 RPM.

Tip: Dress the stone occasionally by running it against a dressing stick or scrap metal to expose fresh abrasive and maintain its shape.

Carbide Burrs

Best for: Aggressive material removal on metal, wood, plastic, and fiberglass. Faster than grinding stones and do not load up with soft materials. More expensive but dramatically more efficient.

Category 3: Polishing and Buffing Attachments

Felt Polishing Wheels

Best for: Applying polishing compound to metal for a mirror finish. Use with tripoli compound for the cutting stage, then rouge for the final shine.

Speed: 10,000-15,000 RPM for polishing. Higher speeds can burn the compound.

Pro tip: Dedicate one wheel per compound color. Cross-contamination defeats the purpose.

Cotton Buffing Wheels

Best for: Final mirror finishing on precious metals and jewelry. Softer than felt, they produce a gentler final touch.

Wire Brushes (Steel / Brass / Nylon)

Steel wire: Aggressive rust and paint removal on steel and iron. Brass wire: Gentler cleaning for softer metals and non-sparking environments. Nylon bristle: Cleaning without scratching — good for aluminum, brass, plastic.

Rubber Polishing Points / Abrasive Wheels

Best for: Deburring and light polishing in tight corners. The rubber matrix wears away slowly, exposing fresh abrasive. No compound needed.

Category 4: Drilling and Routing Attachments

High-Speed Steel (HSS) Drill Bits

Sizes: Typically 1/32 to 1/8 inch included in rotary tool kits.

Best for: Drilling small holes in wood, plastic, and soft metals. Too much lateral pressure will snap them — let the speed do the work.

Speed: 15,000-25,000 RPM for soft materials, 8,000-12,000 RPM for metal.

Router Bits

Best for: Freehand routing, edging, and carving in wood. A rotary tool with a router base attachment becomes a miniature router for inlay work and small joinery.

Category 5: Engraving and Detail Bits

Diamond Burr Points

Shapes: Ball, cylinder, cone, flame, wheel, needle — each for different contour access.

Best for: Engraving glass, stone, ceramic, hardened steel. Diamond points cut by abrasion, not by shearing, so they work on materials harder than HSS.

Speed: 15,000-25,000 RPM. Use water or oil as lubricant on glass and stone to extend bit life.

Engraving Cutters

Best for: Metal engraving — nameplates, tools, jewelry. These have a sharp V-shaped tip that cuts rather than abrades.

Category 6: Specialty Bits

Mandrels

What they are: Not a bit — a holder. Mandrels accept screw-on accessories like cutting wheels, sanding discs, and felt wheels. You need at least one mandrel in your kit. Having two (one for cutting wheels, one for polishing) saves constant swapping.

Collets

What they are: The metal sleeves that grip the bit shank inside the tool. Most rotary tools use 1/8-inch (3.2mm) collets — the industry standard. Some kits include 1/16-inch or 3/32-inch collets for smaller bits.

Which Bits Come in a Typical Kit?

A good starter set should include cutting wheels, sanding drums in multiple grits, grinding stones in at least three shapes, HSS drill bits, diamond burr points, felt polishing wheels, wire brushes, and at least one mandrel. The Hardell Cordless Rotary Tool Kit includes 50+ accessories covering all six categories listed above, so there is no need to buy extras on day one.

Bit Compatibility

Hardell rotary tools use a standard 1/8-inch (3.2mm) collet, making them fully compatible with Dremel accessories and most third-party bits. If you already own Dremel-compatible bits, they will fit without adapters.