Bullone centrale o platorelli con filettatura femmina: quale si adatta alla tua levigatrice?

Quick answer

Choose a center bolt backup pad if your sander uses a bolt that passes through the pad and threads into the tool. Choose a 5/8-11 female thread backup pad if your tool has a male spindle that screws into the pad. Match the pad's mounting style, diameter, and hole pattern to your sander before buying.

Why the arbor style decides the pad, not the disc

Hook-and-loop discs attach to the pad face, but the pad itself must lock onto the sander's spindle. A center bolt pad has a central hole that a bolt passes through; the bolt then threads into the sander. A female thread pad has a threaded hole in its center that receives a male spindle from the tool. These are not interchangeable without an adapter, and adapters can change the pad height and balance.

Check your sander's parts diagram or remove the existing pad to see which style you have. If you see a bolt head on the pad face, you likely need a center bolt pad. If you see a threaded hole in the pad center, you need a female thread pad.

When a center bolt pad is the safer choice

Center bolt pads are common on random orbital sanders and some DA sanders where the bolt is accessible from the pad side. They let you change pads without removing the tool from the workpiece, and the bolt clamps the pad securely. However, the bolt must match the thread in your sander, and the pad must have the correct hole pattern for dust extraction.

If your sander uses a 5/8-11 female thread in the tool, a center bolt pad with a 5/8-11 bolt is not the same as a female thread pad. The bolt passes through the pad and threads into the tool, so the pad itself is not threaded.

When a female thread pad makes more sense

Female thread pads are often used on larger sanders, polishers, and grinders where the spindle protrudes. The pad threads directly onto the spindle, which can provide a lower profile and quicker changes. The trade-off is that the spindle thread must be clean and undamaged; cross-threading can ruin the pad or the tool.

A 5/8-11 female thread is a common spindle size on many angle grinders and polishers. If your tool has a 5/8-11 male spindle, a female thread pad will screw on directly. Always check the spindle length: too long a spindle can bottom out in the pad and prevent proper seating.

Pad diameter and density: match the work, not just the tool

Larger pads cover more area but can be less stable on contoured surfaces. An 8-inch pad is suited to flat, large-area sanding and finishing where coverage matters. Smaller 5-inch pads are more maneuverable and common on random orbital sanders. Density affects conformability: soft pads cushion and follow curves, while firmer pads stay flat for edge work.

Hole patterns must align with your sander's dust ports. A mismatch reduces extraction and can cause dust buildup. Count the holes on your existing pad and compare to the replacement.

Decision rules for buying a backup pad

• Identify your sander's arbor style: Remove the old pad. If a bolt passes through the pad center and threads into the tool, you need a center bolt pad. If the pad has a threaded hole that screws onto a male spindle, you need a female thread pad. Snap a photo of the spindle before shopping.
• Match the thread size exactly: For female thread pads, confirm the spindle is 5/8-11. For center bolt pads, confirm the bolt thread matches your tool. Do not guess; check the manual or measure the spindle with a thread gauge.
• Check pad diameter and hole pattern: Choose a diameter that matches your sander's intended pad size and task. Count the dust holes on your old pad and ensure the replacement has the same pattern or a compatible universal pattern. A pad that is too large can overhang the tool and cause vibration.
• Select density for the job: Soft density pads conform to curves and are good for finishing. Firmer pads stay flat for edge sanding and heavy stock removal. If you need both, start with the density that matches your most common task.

Product facts to compare

• 8" SOLID 5/8"-11 FEMALE THREAD ARBOR BACKUP PAD - SOFT DENSITY(J808) 1" THICK USA H&L: 8-inch diameter, solid 5/8-11 female thread arbor, soft density (J808), 1-inch thick, hook-and-loop face. This pad threads onto a 5/8-11 male spindle and its soft density suits contour sanding and finishing on a large 8-inch footprint.

  

• 5" 8 HOLE 5/8" THICK BACKUP PAD BOSCH RS031 (CENTER BOLT) H&L: 5-inch diameter, 8-hole configuration, 5/8-inch thick, center bolt mounting, hook-and-loop face, Bosch RS031 model. This center bolt pad fits sanders that use a through-bolt and its 8-hole pattern aligns with matching dust ports for extraction.

  

Who should choose which

Best for

• Sanders with a 5/8-11 male spindle that need a large 8-inch soft pad for contour finishing
• Random orbital sanders with a through-bolt and 8-hole dust pattern that need a 5-inch replacement pad

Not for

• Tools with a different spindle thread or bolt size that cannot be adapted safely
• Applications requiring a firm pad for edge sanding or heavy removal