12" Disc Sanders
When you need to quickly and precisely sand outside curves, or fine-tune miters and crosscuts, nothing beats a dedicated 12" disc sander. Its table accepts a miter gauge to deftly sand precise angles for joinery. Yet the heavy disc behind the abrasive makes it aggressive when you need to hog away waste quickly. We took six 12" disc sanders for a test spin, essentially all benchtop machines (though one has an open-leg stand) and priced within reach of the home woodworker. Read on to learn how they fared.
Six important features to look for in a disc sander
1. Ample power. If you have a need for speed in completing your work, a sander must have the power to handle aggressive stock removal without bogging down. To test this, we installed a new 80-grit Klingspor disc on each machine and sanded away 1⁄2 " from the end of 6"-wide pine and oak boards with as much force as each sander could handle.
Of the four sanders with 1-hp-rated motors, the Grizzly G0702 and Jet JDS-12OS demonstrated the most actual power in our testing. The 1⁄2 -hp-rated motors on the nearly identical Delta 31-140 and Rikon 51-200 bogged down easily; backing off the stock-removal rate, though, allowed these two machines to sand capably.
2. A flat platen. The platen is the metal disc that holds the abrasive. All six sanders' platens proved flat, ran with no run-out (wobble), and delivered accurate results when sanding 45° miters and 90° crosscuts. (Although getting the tables and miter gauges to do that proved more of a challenge. Read points 4 and 5 to learn why.)
Because the platens develop so much inertia when running, it's nice to have a brake to stop them rather than risk an injury or workpiece damage by letting them coast to a stop. (Without braking, the cast-iron and steel platens spin for more than two minutes before coasting to a stop; the aluminum platens, about 30–45 seconds.) The Grizzly G0702 has an automatic brake that stops its platen in three seconds; and the Delta, Jet, and Rikon units have manual brakes, shown below.
3. Effective dust collection. Because you make nothing but fine dust with these sanders, it's critical to have effective dust control. All six units, when hooked to a typical 12-gallon tub-style shop vacuum, did a superb job of evacuating dust. We give the Jet bonus points for having a fan-assist built into its dust shroud, and a 2-micron canister that traps dust well without needing a vacuum.
4. A heavy, easy-tilt table. A disc sander's table must resist vibration, tilt easily and accurately, and have a slot for registering a miter gauge and other jigs. All but one tested sander have cast-iron tables that provide a solid surface and resist vibration during use. The Grizzly G7297's aluminum table vibrated steadily as the disc rotated. It did not affect sanding quality, but left our tester's arms tingling afterward. A large table, such as that on the Grizzly G0702, provides more support for large workpieces, but we found the smaller tables proved adequate for most jobs.
Tilting the table proved easiest on the Jet, and rock-solid 45° and 90° stops, shown above, ensured quick, accurate results for the two most common settings. The Delta and Rikon units use a rack-and-pinion geared mechanism, shown below. The other tables use free-sliding adjustments with no positive stops and unreliable scales.
Only the tables on the Delta, Jet, and Rikon sanders have a standard 3⁄8 ×3⁄4 " miter slot, so you can use your tablesaw's miter gauge or build a jig with a store-bought miter bar. The Grizzly G0702 and Jet, shown below, have intersecting (X-Y) miter slots that give you more workholding options.
5. Easy-to-use miter gauge. To sand any angle accurately, you need something to hold the workpiece steady, and a miter gauge is the natural choice. Each machine comes with a miter gauge, shown below, but, unfortunately, none of them have positive stops for common angles, such as 90° and 45°, and their scales proved unreliable. We found it best to set angles using a drafting triangle or reliable combination square rather than rely on the miter-gauge scale. And if we had one of the three sanders with a standard 3⁄8 ×3⁄4 " miter slot, we'd swap the included miter gauge for a more accurate aftermarket model or the one from our tablesaw, or build a jig for that purpose.
6. Easy sanding-disc changes. Eventually, you'll wear out the sanding disc that came with the machine and need to replace it. (Learn how below.) All the test models use pressure-sensitive adhesive (PSA) discs that stick onto the platen. We found it easiest to remove worn discs from the steel-platen Jet. Removing worn discs from Grizzly's cast-iron platen proved most pesky, with aluminum platens somewhere in between. You must remove a shield from the G0702 before changing discs, the only test model with this hiccup.
How to replace a PSA disc in 4 easy steps
Pressure-sensitive adhesive (PSA) discs develop a stronger bond with the sander's platen over time, so it can be frustrating replacing a disc that's been in place for months (or, gulp, years). Follow these step-by-step instructions to take the hassle out of this sticky job.
1. Use a heat gun or blow dryer to soften the disc's adhesive through the abrasive. Then peel the disc away from the platen with a putty knife and your fingers while still applying heat.
2. With the disc removed, soften the remaining adhesive with a solvent, such as lacquer thinner, and scrape it off with a putty knife. Wipe the platen clean with more solvent.
3. Once the platen is clean and dry, peel back half the backing on a new disc and fold it over the other half. Insert the disc between the table and platen as shown, and press the top half in place.
4. Rotate the platen a half-turn, remove the remaining backer, and firmly press the disc to the platen. Rotate and press the disc securely in place.
The top spinners
As you might expect, the higher-priced Jet JDS-12OS outperformed the other machines in many aspects: It earns our Top Tool award. This stand-mounted machine has power to spare, built-in dust collection, a user-friendly cast-iron table with X-Y miter slots, a circle-sanding jig, and the easiest abrasive changes of our test group. It also comes with a five-year warranty. But if the $560 price tag proves too much for your wallet, you can buy the sander without stand and filter (model JDS-12B) for $500.
Jet JDS-12OS, $560
Delta 31-140, $250
Grizzly G0702, $415
Grizzly G7297, $170
Rikon 51-200, $240
Shop Fox W1828, $256
Download PDF of 12" Disc Sander Comparison Chart