Power ToolsAbrasive tool
Random Orbit Sander
An abrasive disc on a free-rotating, orbiting pad. Cuts fast without the directional scratches a belt or drum sander leaves, which is why it is the finishing tool rather than the shaping one.
What it does
- Flattening and smoothing surfaces before finishing
- Removing machining marks and old finishes
- Blending a joint flush
Materialswhat it is used on
All materialsWhat to look forthe judgement calls, before the spec sheet
- Grit is chosen by what it has to remove, not by what feels rough: coarse to remove a saw mark, medium to flatten, fine to prepare a surface for finish. Skipping a step costs more time than it saves.
- Orbit diameter sets how aggressively the disc cuts; the same paper on a larger orbit removes more.
- Dust extraction is a working part of the tool. Without it the abrasive loads up, which is the difference between a disc that lasts a minute and one that lasts ten.
Misuse and safetythe ways this tool causes rework
- It will round over a sharp arris and dish a flat face if held still. Keep it moving, and use a sanding block on anything that has to stay square.
- Crossing from one grit to a finer one with dust still on the work puts the coarse particles back into the surface as scratches.
Projects that call for itand what it is doing on each one
All projectsFrequently asked questions
Should I sand between coats of finish?
Lightly, with a fine grade, to knock off the raised grain and give the next coat something to key to. The objective is to flatten the surface, not to remove the finish.
Random orbit or belt sander?
A belt sander removes material along the belt's direction and leaves those marks; a random orbit sander leaves no direction and is easier to control. Use the belt to dimension, the orbit to finish.