Whether sanding curves or straightening edges, look to the oscillating spindle sander for a smooth performance.
By The Editors
If you build furniture, you are already familiar with the most useful sander in your arsenal, the random orbit sander. It quickly smoothes out any surface you may have…as long as it is flat. When it comes to sanding curves you need a different tool – an oscillating spindle sander (OSS).
An OSS is a very basic machine that consists of a tabletop with a sanding drum protruding through a hole in the top. The drum is covered with an abrasive sleeve, and as well as rotating, it moves up and down (oscillates). The oscillation ensures that a larger surface area of the sleeve is used, with the result that the abrasive will not become clogged as quickly. The oscillation also eliminates the chance that unevenness in the abrasive will cause a consistent scratch pattern along the length of the work piece. We shop tested four models commonly available through Canadian retailers. They ranged in price from a low of $139 for the Triton to a top end of $299 for the Craftex.
All of these sanders have a cast iron top, except the King, which uses heavy-duty aluminum. The tops on all four models were flat, with no measurable gaps. All but the Delta have a square or rectangular table top. We particularly liked the large 14″ x 20″ top on the King. The smaller top on the Triton made it somewhat less convenient when sanding long, wide stock. The use of plastic for the base and housing on the King and the Triton make them, at around 30 pounds, the lightest in the group, a plus when you must move them regularly in a small shop. While we found that none of these machines wandered in use (rubber feet hold them firmly in place on the bench) it is still a good idea to bolt them to a work bench, or onto a sheet of ply which can be firmly clamped to a work bench. Optionally consider mounting them on a rolling cabinet to save your back, something you’ll definitely want to consider with the 65 pound Craftex.
The sanding drums are installed onto a metal shaft that penetrates the top. The shafts on all the sanders were aligned 90º to the tabletops. All models have a ½” shaft that accept 5″ (4-1/2″ nominal) drums, except the Craftex which has a 1/2″ shaft and takes 6″ (5 1/2″ nominal) drums. The Delta and King come with 3/4″, 1″, 1-1/2″, 2″ and 3″ diameter drums. The Triton includes these five sizes plus a 1/2″ sleeve, which doesn’t use its own drum; it simply slips over the metal shaft. The Craftex comes with three drums sizes – 1/4″, 5/8″ and 2″. The 1/4″ drum comes with a separate shaft.
An abrasive sleeve slips over the drum and is held in place by a retaining nut or bolt. When changing the size of the drum, you’ll also need to adjust the size of the opening in the tabletop as well to keep the gap as small as possible. This is done by means of metal or plastic (ABS) inserts, which come in various sizes to accommodate the different drums. The inserts act like the throat plate on your table saw to keep material from getting caught between the edge of the table and the edge of the drum. Sanding sleeves are generally available in 50, 80, 120 and 150 grits. All the sanders have on-board drum and insert storage.
On the Craftex the top tilts up to 45º to accommodate sanding at other than 90º. To accommodate the tilting top, the inserts that fit around the drums come in two forms, a regular circular version that is used when the spindle is at 90º and one with elongated holes for use when the table is tilted.
All of these machines provide a connection port for a dust collector or vacuum system and with these ports varying in size from 1-1/2″ to 2-1/4″ you will likely need to fit an adaptor depending on the system you use. The Delta has a dust collection bag that fits over the dust port to capture the dust ejected by the internal fan. However it doesn’t collect much of the fine dust. The Triton comes with a 1-1/2″ to 4″ adapter that makes it a snap to connect to a standard dust collection system. The 2 ¼” dust port on the King was the easiest for us to hook up to a shop vacuum – the others required us to search around the shop for suitable adapters.
Spindle sanders are quieter than other shop machinery, operating from a low of 65.1dB (no load) on the Delta to a high of 87dB on the Triton. We found that all the sanders worked well regardless of motorsize, which ranged from a low of 2.4 amps on the King to a robust 7.5 on the Craftex. On any of these sanders, except the Craftex, you can inadvertently stop the oscillating movement of the drum by pressing stock too forcefully against the drum. Bear in mind that you let the machine do the work here, steady pressure is all you need. The stroke on these machines (the distance that the drum oscillates), varies from 5/8″ on the King and Triton sanders, to 1″ on the Craftex. Having a longer stroke not only means that more of the sanding abrasive is used, it also helps reduce heat build up and thus diminishes the risk of getting burn marks on your stock. Not an issue of you are sanding a couple of small pieces, but helpful when sanding a quantity of wide, long stock.
Wider table for long stock
On board drum storage
An OSS can handle curved parts with ease and is the natural choice when fairing a curve or sanding a curved edge. These sanders ship with an assortment of drum diameters to suit the most common sizes of curves you’ll be working with. When you are sanding, always select the largest drum that will accommodate the smallest curve on your work piece. Whether you are sanding the edge of a plywood pattern or the edge of a final project component, bringing the work to the drum requires the right technique for a smooth result. For best results it is best to take long, flowing, light passes; bring the material to the edge of the drum as you move it side to side and run it along the edge in a skimming motion and then pull it away at the end. Repeat this until you have sanded to the line or refined the shape to your needs. Trying to sand away the entire waste portion up to the line in one go by moving the material slowly over the drum will result in an uneven surface showing scalloped edges where the wood has assumed the shape of the drum’s curve because of uneven feed pressure and speed.
Sanding curved pieces
Extend Abrasive Life
As the abrasive sleeves are used they will begin to load up with the material that is being sanded. The oscillations will extend the life of the abrasive but the sleeves will eventually clog. Fine abrasive sleeves will clog quickly with most woods while certain woods such as pine will clog even rough abrasive sleeves. When this happens you can clean the sleeve using a crepe block which is essentially a large rubber eraser. When the crepe block is applied to the rotating drum, the rubber is sanded off the block and the process warms up the edge of the crepe block. The material embedded in the sanding sleeve bonds to the warm, somewhat sticky bits of the block as it is sanded down, and is quickly removed from the abrasive sleeve.
If you find most of your work involves thinner stock and only wears on one end of the sleeve, when that end is worn, remove the sleeve and reinstall it upside down to use the abrasive on the other end. If the center of the sleeves consistently remains unused, consider making a spare top out of MDF to raise the work piece higher on the sleeve. Embed some rare earth magnets in the underside to hold it fast to the cast iron top.
With the addition of a simple jig made from a piece of wood you can use your spindle sander to sand straight edges or to straighten an uneven edge on a board. Prepare a piece of lumber to be flat and square and then use a hole saw to cut a hole 1″ larger than the sanding drum into the midpoint of the board along its length. Offset the hole to one side so there is an opening in the edge of the board so the surface of the drum can sit just slightly proud of the edge. Run the edge of the material back and forth over the slightly exposed drum until the edge has been sanded straight and smooth. Gluing a piece of laminate to the surface of the out feed side will more closely approximate the function of a jointer but this is not necessary for the jig to function adequately.
We used these four sanders over a one-month period in the shop. The Triton, at just under $140, is the price leader. Features we like include its cast iron top, inclusion of a 1/2″ drum size, particularly convenient for sanding tight curves, light weight, and three year warranty. Its main drawback is a small tabletop. As well, the oblong shape of the top makes it less convenient when sanding larger stock. The King is the lightest unit – easy to move from storage to tabletop with minimal back strain. It also has the largest table, made of precision cast aluminum, so you don’t have to worry about rust. The spindle is offset, which makes for a lot of usable tabletop. And, its 2-1/4″ dust port is the only one that accepted our vacuum hose without having to search around for an adapter. The Delta is a solid, heavy unit that features a round cast iron tabletop and removable drum trays. Quiet tools always get us smiling, and we liked its low, 65.1 dB rating. A five year warranty is a nice bonus as well. While we feel that either of these three will easily meet the needs of the DIYer or weekend woodworker, we gravitated toward the King, because of the large table, light weight and steel insert rings. However, if you do a lot of contour sanding, then we recommend the Craftex. Its main advantages are the tilting tabletop and the longer drum sizes. It’s the only one that comes with a ¼” drum as well. Its faster speed (74 oscillations per minute) and longer stroke (1″) gave the best finish among these sanders.
This Just In
We didn’t have time to review the General 15-220, but it has a number of notable features that make it worth considering. It has a 1/2 HP, 7.5A motor, precision ground 14-1/2″ x 14-1/2″ cast iron table, five spindle assemblies (1/4″, 1/2″, 5/8″ 1-1/2″ and 2″), and 2″ dust port (with a 2″ to 4″ adapter), all in an 81 lb package. Best of all, the 15-220 comes with a tilting table. 2 year warranty. $479. general.ca