Sanding convex and concave surfaces just became easier. 

The Delta Boss Ossillating Spindle Sandermakes smooth work out of any rough surface.



Sanding convex and concave curves can be challenging at the best of times especially if the band saw or jig saw blade used to cut these curves has left the surface of the cut, rough.  The remedy for most woodworkers has been to place a sanding drum in the drill press and try to sand the offending curve smooth.  The outcome was usually less than perfect.

The answer to this dilemma is the Delta SA350K BOSS Oscillating Spindle Sander. The BOSS is a spindle sander that not only rotates sanding drums of various diameters but also moves the sanding drum up and down as it rotates reducing the amount of time and effort spent sanding curves and of course, eliminating the burning that usually occurs when using sanding drums in the drill press.

Powered by a ¼ horsepower motor and having a stroke of 7/8” the BOSS delivers 60 strokes per minute, more than adequate for light to medium duty work and it’s fixed cast iron table top is a full 18” in diameter which is large enough to handle large work.

The BOSS has a dust collection bag on the back of the machine and I found it adequate for work I was doing but the bag can be easily removed and the machine can be attached to a dust collector via the 1 ½” dust port on the machine.

The assembly of the machine was straight forward and the instruction manual was easily understood. In the event that the spindle and the table are not square to each other, shims can be placed between the table and the housing but my spindle and table were dead on right out of the box.

The BOSS came with 5 sanding drums and the corresponding 4” diameter table inserts for each size of drum. (¾”, 1”, 1 ½”, 2”, & 3”) and when not in use, these drums, table inserts and the accompanying tools and washers needed for the operation of the machine store neatly in the machine’s two onboard storage compartments. Changing from one size sanding sleeve to another was easy with the supplied socket wrench



 The machine tips the scales at 45 pounds which makes it light enough to use as a bench top sander and store under the bench when not in use or with the 4 pre-drilled holes in the plastic base mounting this sander to a stand is easy work. I found that setting the BOSS right on the workbench worked best for me. The BOSS ran smooth as silk, with no vibration and no noise to speak of.


With it’s large diameter cast iron top, 5 different size sanding drums, smooth running motor and onboard storage, this oscillating spindle sander has earned it’s name, THE BOSS and is more than adequate for light to medium duty work.

 Note: The purchase of a crepe block will prolong the life of any sanding drum by using it regularly to clean the sanding drum.

 Manufacturer’s Specifications:

       Large, cast-iron table measures 18″ dia. to support large work pieces

  • Heavy-duty motor assembly features a powerful, 1/4 HP induction motor with direct drive for quiet, smooth operation. Replaceable oil-impregnated bearings and sturdy, ground-steel rods for support
  • Built-in dust collection fan draws in dust and chips through a specially designed table insert and deposits debris in the standard-equipment dust bag
  • Pre-drilled base holes for mounting sander to a stand or workbench
  • Toggle switch with removable lock out key prevents unauthorized use
  • Comes complete with table insert for accepting standard-equipment 3/4″ diameter sanding drum and sleeve. Four accessory table inserts are also available for using sanding drums from 1″-3″ in diameter.
  • Two built-in compartments make it easy to store accessory sanding drums and sleeves
  • Motor: 1/4 HP, 120V, 1 Phase, 60 Hz, 1,725 rpm
  • Stroke: 7/8 “
  • Strokes/Min: 60 spm
  • Drum Size: Minimum: 3/4″; Maximum: 3″ “
  • Spindle Diameter: 1/2 “
  • Speed: 1,725 rpm
  • Abrasive Belt Size: NA “
  • Disc Diameter: NA “
  • Table Size: 18 “
  • Table Insert: 4″
  • Dust Collection Outlet: 1-1/2 “
  • Table Tilt: NA °
  • Miter Gauge Groove: NA
  • Height: 15 “
  • Length: 18 “
  • Width: 18 “
  • Weight: 45 lbs
  • Shipping Weight: 55 lbs