3M 05556 Stikit Low Profile Abrasive Disc Backup Pad 6 in | Firm Foam, 15° Taper, 3/8 in Thick | PSA Stikit Disc Attachment | 10,000 RPM | 5/16-24 EXT Thread for DA & Rotary Sanders

3M 05556 Stikit Low Profile Abrasive Disc Backup Pad 6 in — Firm Density Foam | 15° Tapered Edge | 3/8 in Thick | PSA Stikit Disc Attachment | 10,000 Max RPM / 12,000 Max OPM | 5/16-24 EXT Thread | For DA & Rotary Sanders

3M Stikit Low Profile Abrasive Disc Backup Pad provides secure attachment for 3M Stikit PSA (pressure-sensitive adhesive) abrasive discs on a random orbital, dual-action (DA), or rotary sander. Constructed of firm-density foam with a low-profile 3/8 in. thickness and a 15° tapered edge for better edge support and access in block sanding and flat surface work. Lightweight, shock-resistant construction. 6 in. diameter. 5/16-24 EXT thread for direct mounting on compatible sander spindles. Stikit abrasive discs sold separately.

Part Specifications

• Part Number: 3M-05556
• Product Line: 3M Stikit Abrasive Disc System
• Diameter: 6 in.
• Thickness: 3/8 in. (low profile)
• Taper: 15° tapered edge
• Density: Firm
• Construction: Firm-density foam, lightweight, shock-resistant
• Disc Attachment System: Stikit PSA (pressure-sensitive adhesive) — accepts 3M Stikit abrasive discs only
• Thread Size: 5/16-24 EXT (external thread for direct sander spindle mount)
• Max Speed: 10,000 RPM / 12,000 OPM
• Compatible Tools: Random orbital (DA) sanders and rotary tools with 5/16-24 EXT spindle thread
• Discs Required: 3M Stikit PSA abrasive discs, 6 in. (sold separately)

Stikit vs Hookit — PSA vs Hook-and-Loop Disc Attachment Systems

3M produces two primary abrasive disc attachment systems for random orbital and DA sanders — Stikit (PSA) and Hookit (hook-and-loop). These systems are not interchangeable — each requires its own matching backup pad. Using the wrong disc type on a backup pad will result in poor disc adhesion, disc separation during sanding, or pad damage:

• Stikit — PSA (pressure-sensitive adhesive) — this backup pad (3M-05556):
  • Stikit abrasive discs have a peel-and-stick PSA backing that adheres directly to the smooth face of the Stikit backup pad
  • Disc is pressed onto the pad face and bonds on contact; disc is peeled off when worn or when changing grits
  • PSA discs can typically be repositioned a limited number of times before the adhesive loses tack; clean the pad face between disc changes for best adhesion
  • Stikit backup pads have a smooth foam face — no hook material
• Hookit — Hook-and-Loop:
  • Hookit abrasive discs have a loop fabric backing that attaches to the hook face of a Hookit backup pad
  • Discs attach and detach quickly without peeling adhesive — faster disc changes than PSA
  • Hookit discs available in catalog: 3M 01817 Hookit P150 Purple Clean Sanding Disc 6 in 50-Pack
  • Hookit discs require a Hookit backup pad — not compatible with this Stikit pad (05556)

Key rule: Match the disc system to the backup pad. Stikit PSA discs on a Stikit pad (this product). Hookit loop-back discs on a Hookit pad. Do not attempt to use PSA discs on a hook-face Hookit pad or vice versa.

Low Profile Design — Why Pad Thickness and Taper Matter

The low-profile 3/8 in. thickness and 15° tapered edge of the 05556 are functional design features, not just dimensional specs:

• Low profile (3/8 in. thick vs standard ~5/8 in. pads): The reduced thickness lowers the sanding plane closer to the tool, reducing tool vibration transfer to the pad edge and providing more stable, flatter sanding on panel surfaces. Better for flat surface sanding where consistent, even pressure across the full disc face is critical.
• 15° tapered edge: The tapered edge allows the disc to flex slightly at the perimeter without the hard edge of the pad digging into the surface. This is particularly useful for block sanding work and for feathering paint edges where the outer portion of the disc needs to work close to a surface boundary without leaving edge marks.
• Firm density foam: Maintains a flat, even sanding plane across the disc face. Softer pads conform to contours but can produce uneven scratch patterns on flat surfaces — firm density is the correct choice for flat-panel sanding and production work.

Application Notes

• Confirm the sander spindle thread is 5/16-24 EXT before mounting — this is the standard thread for most 3M Stikit backup pads on DA and rotary sanders; check your sander’s specifications if unsure
• Use only 3M Stikit PSA abrasive discs with this backup pad — do not use Hookit (hook-and-loop) discs on this pad
• Clean the pad face before installing a new Stikit disc — abrasive dust and adhesive residue on the pad face reduce disc adhesion and can cause the disc to release during sanding
• Do not exceed 10,000 RPM or 12,000 OPM — operating above rated speed risks disc separation and pad failure
• Inspect the pad face regularly for wear, glazing, or adhesive buildup; replace the backup pad when the foam surface is no longer flat or when Stikit discs no longer adhere securely
• Store the pad with a used or scrap Stikit disc attached to protect the PSA-ready foam face from dust and contamination between uses

Additional Information

• Vendor: 3M
• SKU: 3M-05556
• Product Type: Abrasives / Sanding Accessories
• Diameter: 6 in.
• Thread: 5/16-24 EXT
• Max Speed: 10,000 RPM / 12,000 OPM
• Country of Origin: USA
• HS Code: 8466.20 (work holders for machine tools — verify; abrasive pad holders may classify under 6805 accessory items — verify for your import classification)

Frequently Asked Questions

Q: What is the difference between Stikit and Hookit backup pads, and can I use Hookit discs on this pad?
A: Stikit pads (this product) have a smooth foam face for PSA (pressure-sensitive adhesive) Stikit discs. Hookit pads have a hook-face for loop-back Hookit discs. The two systems are not interchangeable — do not use Hookit discs on a Stikit pad or vice versa. If you are using 3M Hookit discs (such as 01817), you need a Hookit backup pad, not this product.

Q: What thread size is the 05556 backup pad, and how does it mount to a sander?
A: The 05556 uses a 5/16-24 EXT (external) thread that screws directly onto the spindle of compatible random orbital and DA sanders. Check your sander’s spindle thread specification before ordering — some sanders use a different thread size or require an adaptor.

Q: Why is a low-profile pad better than a standard-thickness pad for flat panel sanding?
A: The reduced 3/8 in. thickness lowers the sanding plane closer to the tool, improving stability and producing more consistent, even pressure across the disc face on flat surfaces. Standard-thickness pads sit higher off the tool, which can increase vibration transfer to the pad edge and make it harder to maintain a perfectly flat sanding plane on panels.

Q: What does the 15° tapered edge do?
A: The 15° taper allows the disc perimeter to flex slightly without the hard edge of the pad digging into the surface. This prevents edge marking and allows the disc to work close to surface boundaries — useful for feathering paint edges and for block sanding work where the outer portion of the disc needs to sand right up to a panel edge.

Q: Can this backup pad be used on a rotary polisher as well as a DA sander?
A: Yes — the 5/16-24 EXT thread is compatible with rotary tools as well as DA/random orbital sanders, provided the rotary tool uses the same thread size. Do not exceed the rated 10,000 RPM maximum speed regardless of tool type.