Craftsman 315279890 5" random orbital sander Parts

For the Craftsman 315279890 5-inch random orbital sander, the motor input is 120V, 60 Hz, 3.0 amps, which works out to about 360 watts (120 × 3.0). That is the electrical power the tool draws; sanding performance also depends on speed setting, pad condition, and sandpaper grit. See the 315279890 operator's manual for the full specifications.

Quick wattage math (for model 315279890)

• Voltage: 120 volts AC
• Current draw: 3.0 amps
• Approximate watts: 120 × 3.0 = 360W
• Variable speed range: 7,000 to 12,000 OPM (orbits per minute)

What “watts” means on a random orbital sander

Watts is the input power draw from the outlet. It helps compare tools, but it is not the only factor that determines how fast the sander removes material.

What affects real-world sanding power

• Speed setting (higher OPM removes more material but can increase swirl risk)
• Sandpaper grit and quality (coarser grits cut faster)
• Backing pad condition (worn pads reduce control and efficiency)
• Dust collection (clogged paper cuts slower and runs hotter)
• Pressure and technique (too much pressure can stall the pad and leave marks)

Typical wattage ranges (for context)

Most 5-inch random orbital sanders land in a moderate power range for household and shop use.

Sander type	Typical input power	Typical use
Light-duty 5-inch ROS	200 to 300W	Small projects, light finishing
Mid-range 5-inch ROS	300 to 500W	General sanding, paint prep
Heavy-duty/pro-grade	500W+	Faster stock removal, frequent use

Why it matters

Knowing the approximate wattage helps you set expectations for material removal rate, choose the right extension cord gauge, and troubleshoot issues like bogging down or overheating when sanding.

Parts and diagrams

If you are looking up replacement parts by model number, start with the parts list for Craftsman 315279890, or search our catalog on Sears PartsDirect.

Last updated: February 2026

A finishing sander (often called an orbital finishing or sheet sander) moves the pad in a small orbit and typically uses rectangular sandpaper sheets, while a random orbital sander like the Craftsman 315279890 combines orbiting and spinning motion for a more swirl-free finish and faster stock removal. See the 315279890 owner's manual for the motion description and operating basics.

Quick comparison

Feature	Finishing (orbital) sander	Random orbital sander (Craftsman 315279890)
Sandpaper format	Rectangular sheets (commonly 1/4, 1/3, or 1/2 sheet)	5-inch hook-and-loop discs
Motion	Orbit only	Orbit plus rotation (random orbit)
Typical results	Very controlled, good for final smoothing	Faster sanding with reduced visible swirl patterns
Best use cases	Flat panels, edges, light finish sanding	General sanding, blending, paint prep, leveling between grits

How the 315279890’s sanding action changes results

Our Craftsman 315279890 uses random orbit motion, which overlaps sanding paths by combining orbital and spinning movement. That overlap helps hide directional scratch lines that are more common with straight orbital sheet sanders.

Key features that affect performance:

• Random orbit motion for overlapping scratch patterns
• Variable speed dial (A to F) to match the material and grit
• Pad brake to help protect the work surface by controlling no-load orbits
• Hook-and-loop disc attachment for quick disc changes

Choosing the right tool for the job

Use this checklist to decide:

• Choose a finishing sander when you need maximum control on large, flat surfaces and you are doing light material removal.
• Choose a random orbital sander when you want faster leveling, better blending, and fewer visible sanding swirls.
• For either tool, step through grits from coarse to fine until the surface is uniform.

Why it matters

The sanding motion determines the scratch pattern you leave behind. Random orbit sanding is designed to reduce repeatable scratch lines, which means less time chasing swirl marks before stain, paint, or clear coat.

Parts and documentation help

For diagrams, disc attachment details, and operating features for the Craftsman 315279890, use the parts list for this model or search by model number on Sears PartsDirect.

Last updated: February 2026

For most finishing work, we recommend a 5-inch random orbital sander like the Craftsman 315279890 because it can level surfaces quickly while still leaving a smooth, swirl-minimized finish when you step through finer grits and let the tool’s weight do the work. For the best results, follow the grit progression and operating tips in the owner's manual.

Best sander type for common “finishing” jobs

Different sanders excel at different finishing tasks; here’s how we match the tool to the surface.

• Random orbital (5-inch): Best all-around for furniture, doors, trim, and between-coat sanding
• Sheet/orbital (1/4-sheet or 1/2-sheet): Best for flatter panels where you want a very uniform scratch pattern
• Detail/palm sander: Best for corners, profiles, and tight spots
• Hand sanding block: Best for final touch-ups and breaking edges

Grit selection that produces a true finish-ready surface

The biggest “finishing” difference usually comes from abrasive choice and grit steps, not the tool brand.

• Start coarse only if the surface is rough or has defects
• Move to medium to remove coarse scratches
• Finish with fine grits for the final surface
• Keep sanding with each grit until the surface looks uniform
• Use synthetic abrasives (aluminum oxide or silicon carbide) for power sanding

Typical grit progression (most wood finishing)

Task	Common grit range	Goal
Leveling/paint removal	60 to 100	Flatten and remove defects fast
Pre-finish smoothing	120 to 180	Remove visible scratches
Final prep (most finishes)	180 to 220	Finish-ready surface
Between coats	220 to 320	De-nib without cutting through

Technique tips that prevent swirl marks and uneven spots

The Craftsman 315279890 manual guidance is simple and effective: don’t force the tool.

• Move the sander slowly in overlapping passes (parallel lines, circles, or crosswise)
• Use light pressure; extra pressure slows the motor and can worsen the finish
• Avoid staying in one spot too long (heat can soften resin/finish and gouge the surface)
• For dust collection performance, align disc holes with the pad holes
• If the tool feels hot, run it no-load briefly to cool the motor (off the workpiece)

Why it matters

Finishing is about controlling scratch pattern and heat. A random orbital sander plus the right grit steps gives you a consistent surface that stains and clear coats evenly, with fewer visible sanding marks.

For replacement parts and diagrams for your Craftsman 315279890 sander, start with the model parts list, or search by model on Sears PartsDirect.

Last updated: February 2026

For most deck sanding, we use a belt sander for fast removal on large, flat boards, then switch to a random orbital sander like the Craftsman 315279890 for smoothing and finish sanding with fewer swirl marks. Use the random orbital for edges and between boards where control matters.

Best choice by deck task

• Heavy leveling (cupped boards, old finish, paint): belt sander
• General smoothing and finish sanding: random orbital sander (5 inch)
• Edges, railings, tight spots: random orbital sander (or a detail sander)
• Final prep before stain or sealer: random orbital sander with fine grit

Grit progression we recommend

Start coarse only if you need it; always move to finer grits until the surface is uniform.

• 36 to 60 grit: stripping and flattening (belt sander)
• 80 grit: blending and removing coarse scratches
• 100 to 120 grit: final sanding before most stains

How to get better results with the Craftsman 315279890

This model uses random orbit motion (orbital plus spinning) and supports dustless sanding when the disc holes line up with the backing pad holes.

• Unplug before changing discs
• Align disc holes to pad holes for dust collection
• Press the hook-and-loop disc firmly for good adhesion
• Empty the dust bag when it is about half full
• If the motor overheats, run the sander off the workpiece to cool it

Quick comparison

Feature	Belt sander	Random orbital sander (Craftsman 315279890)
Material removal	Very fast	Moderate
Risk of gouging	Higher	Lower
Finish quality	Fair without follow-up	Better for final finish
Best use	Big flat areas	Smoothing, blending, edges

Why it matters

Deck boards are soft and easy to dish out. Using a belt sander only for the rough work, then finishing with a random orbital sander, helps you avoid uneven spots and improves stain absorption for a more consistent look.

For operating details like variable speed control and dust bag setup, follow the 315279890 operator's manual. If you need to look up replacement parts by model number, we recommend starting with the parts list for 315279890, or searching on Sears PartsDirect.

Last updated: February 2026

Yes. On the Craftsman 315279890 5-inch random orbital sander, the sanding disc backing pad (the hook-and-loop pad the discs stick to) is a replaceable wear part. Replace it when the hook material is worn smooth, the pad is damaged, or the pad brake no longer stops the pad quickly.

When the backing pad should be replaced

Replace the backing pad if you notice any of these common symptoms:

• Sanding discs will not stay attached or peel off during use
• The pad surface is torn, melted, gouged, or out of round
• Excess vibration, chatter marks, or uneven sanding
• Dust collection gets worse because the disc holes no longer align well
• The pad takes longer than about 6 seconds to stop when you turn the tool off (brake and pad system issue)

Basic replacement and setup checklist

We follow these steps to keep the repair safe and to protect the tool:

• Unplug the sander before removing the sanding disc or working near the pad
• Remove the sanding disc and inspect the hook-and-loop face for wear
• Check the pad brake operation by running the sander off the workpiece with no disc installed; the pad should stop quickly
• Install the replacement backing pad using the correct fastener pattern for this model
• Reinstall a disc and align the disc holes with the backing pad holes so the dustless feature works properly

Hole alignment matters (dustless sanding)

Your 315279890 uses a holed disc and backing pad for dust collection. If the holes do not line up, airflow drops and sanding dust builds up faster.

What you see	What it usually means	What to do
Dust stays on the surface	Holes misaligned or clogged	Re-seat disc; clean pad face
Disc won’t stick well	Hook material worn or dirty	Brush-clean pad; replace pad
Pad coasts too long after shutoff	Brake worn	Replace the brake (and inspect pad)

Why it matters

A worn backing pad reduces control and finish quality, increases vibration, and can overload the motor during longer sanding sessions. Keeping the pad and brake working correctly helps protect your work surface and the tool.

For model-specific diagrams, fasteners, and operating notes (including brake checks and disc attachment), use the 315279890 owner's manual. For ordering the correct replacement parts by model number, search on Sears PartsDirect.

Last updated: February 2026