Sanding is the longest noisy job in most workshops. A saw cut lasts seconds; sanding a tabletop through three grits can take an hour with the tool a foot from your head. That makes a sander's declared noise worth more attention than its motor size, and it makes the gaps between makers large enough to notice.
Fourteen 5 and 6 inch random orbital sanders sold in the US carry maker declarations we could read. At the operator's ear they run from 68 to 89 dB(A). Sound power runs from 78 to 97.
The test behind the numbers
Sander makers selling in Europe declare noise under EN 62841-2-4, the standard for handheld sanders and polishers. It gives two quantities. LpA is sound pressure at the operator's position. LWA is sound power, the sander's total output. Each comes with a K value, the uncertainty, usually 3 dB.
We rank on LpA and show LwA beside it. Both come from the same test, but they measure different things and never belong in one ranking. The sound power vs sound pressure explainer covers why.
Festool declares every sander it makes, on its international site, with both quantities, the K value and the standard. Its US pages use the same specification tables with the noise rows gone, and the US operating instructions we opened for the ETS 125 REQ carry no declaration either.
We quote the international figures and match each US article number to its international twin. The names are identical, and so are the motor power, speed range and weight on both pages. One caveat applies to all of them: the declarations describe the 230 V tools, and the US tools run on 120 V.
On those figures Festool takes the top four places. The cordless ETSC 125 declares 68.00 dB(A) at the ear and 79.00 sound power. The brushless ETS EC 125/3, EC 150/3 and EC 150/5 all declare 69.00 and 80.00, so stroke length made no difference in Festool's own tests. The cheaper ETS 125 REQ declares 73, and the newer ETSC 2 cordless sanders 74 and 76.
Mirka is the one maker that prints the full declaration for the exact tool a US buyer gets. Its DEROS II manual for the US, Mexico and Canada covers the 110 V 350X, 550X, 625X, 650X and 750X. Every 5 and 6 inch model declares 71 dB(A) at the ear and 82 sound power with a K of 3.0, and Mirka's US pages repeat a 71.0 dB noise level. Mirka also lists its own prices: $616.41 for the 550X or 650X without a case, $701.45 for the 625X.
Metabo prints noise figures on its US product pages, which few makers do. The trouble is that they disagree with its manual. For the 5 inch SXA 18 LTX 125 BL the US page gives 70 dB(A) at the ear; the manual, declared under EN 62841-2-4 for the same serial number, gives 67. For the 6 inch SXA 18 LTX 150 BL the page gives 89 and the manual 86. Both gaps are exactly the K value, and the two documents also disagree on weight and vibration.
We rank Metabo on the higher US page figure. That puts the 125 BL fifth at 70, and the 150 BL last at 89.
Makita and the ROTEX
Makita's US page for the corded BO5041K links a manual declaring 81 dB(A) at the ear and 92 sound power, K 3, under EN60745, the older standard that EN 62841 replaced. The US manuals for its BO5031K, BO6050J, cordless XOB01 and BO4556K palm sander carry nothing.
Festool's gear driven ROTEX RO 150 is a different kind of machine, with a rotary mode for fast removal. It declares 85 dB(A) at the ear and 96 sound power in every mode, 17 decibels above the ETSC 125.
The silent aisle
Bosch prints no noise in the US manuals for its ROS20VSC corded sander or GEX18V-5 battery sander. DeWalt prints none in the US manuals for its DCW210 battery sander or DWE6420, DWE6421 and DWE6423 corded sanders. Milwaukee prints none in the manual for its M18 2648. RYOBI's US page for its 18V ONE+ 5 inch sander shows no figure. These are some of the best selling sanders in the country, and none of them can be ranked here, whatever they sound like in use.
We did not measure any of these sanders. Every figure is the maker's own, quoted as published, with the standard, K value and document identified wherever the maker identified them.
