Beginners treat all lumber as equal, but experts use each board to its best advantage. I set my random-orbit sander to maximum speed for any grit I’m using and leave it there all the time. And how much is too much? It's normal to see it spin without a load on it, all orbital sanders work this way. We tested off-the-board starts with a running sander; we lowered the sander straight down; and we also practiced bringing it in for a landing. Look for an... read more. The sander should be allowed to spin freely and under its own weight plus light hand pressure. Normally, a random-orbit sander cuts connected ringlets, like those pictured, which are blended away as the machine works and as passes overlap. A proper and correct speed … I confess that I do not adjust the speed of my R.O. In any case, they mean you aren't done sanding. sanders at all. This is a strangely shaped plastic/rubber/polymeric "ring" on the Makitas. 20V 5" Random Orbit Sander (Battery Not Included) The 20V Random Orbital Sander delivers up to 10,000 RPM for fast material removal. Consequently, working with this tool is not so tiring like belt sanders or traditional pad. Rigid Orbital Sander Stops Spinning with Light Pressure. The pad is linked directly with the tool’s motor and therefore gets its full power. For more related content, subscribe to our newsletter! We made additional observations using a stopwatch and rules. These sanders are helpful for cutting more aggressively than other sanders. If you get a bearing with regular contact seals, it will cause the spinning. If it wears out, you will get the spinning. Sander not getting enough power; Weak power source; The filter is not collecting enough dust. In this picture, the optical tachometer shows a sander, rated at a no-load speed of 12,000 orbits per minute, approaching its top speed under normal load. Turn off the orbital sander and flip it over. We sprinkled in a few other soft- and hardwoods for good measure. The regulator of the speed controller is connected to the transistor and the potentiometer using a few wires. The second cause is a worn out brake. It ensures that the orbital action will work properly so the grit abrades the surface as efficiently as it can. This makes off-the-board starts dicey for older, brakeless sanders. It is specially designed to oscillate in a random fashion giving a non-repeating motion and a swirl-free surface. But that doesn't mean there's nothing to learn. We resawed the pine samples (top pair) from one board. Beyond that, I’m not certain that variable speed control makes much difference at … Hello, I just bought a new random orbit sander, the small festool one, and was wondering how fast the disk should spin. Setting 1 isn’t recommended for any sanding situation. Here's how we tested these techniques. It is not supposed to spin fast while sanding. Hold the new sandpaper above the orbital sander pad, lining it up and making sure it is the proper size. We analyzed scratch patterns after each test. This picture shows a cherry board finished with a water-based poly-acrylic. We worked on both clamped and unclamped work pieces, and screwed boards to the wall to see if vertical starts would create issues we hadn't seen on horizontal starts. We double-checked the feed-rate settings by using our tach to count wheel revolutions. Really can’t see much difference in the final surface. Knowing the RPMs and diameter of the wheel allowed us to figure inches per second of travel. A correct pace is about 1-inch per second. When you first try it, that speed will seem SO SLOW! Velcro Came Off; Plastic Broke Off; Sand Disc Falls Off; Sander heats up too fast. All Rights Reserved. While the dial can be set from 1 (low) to 6 (high) speed, the recommendation is from 4 to 6 on all surfaces and with all sanding grits besides light sanding on paintwork (2 to 3 is recommended, in grits ranging from 180 to 400). Both examples show that roughly sanded wood (right top and bottom) holds more stain or finish, and therefore is apt to be darker, than fine-sanded wood (left top and bottom). © 2021 Meredith Corporation. Scrollsaw, Carving, and Decorative Projects. We focused mainly on polyurethane finishes, conducting trials at full speed and several slower settings. Turn the orbital sander on its side. So we bought a Rigid R26011 about a month and a half ago and after only maybe 5 or 6 hours of use, the pad will stop spinning with just the smallest amount of pressure. Interestingly, a manual that came with a Bosch variable-speed R.O. Here’s how we tested conventional power-sanding wisdom—and found out it wasn’t always so wise—for the October 2008 issue of WOOD magazine. Our test apparatus (pictured) employed small dumbbell weights centered above the sander on a dowel. Push down firmly on the sandpaper. Disc speed is one thing, but how fast should you move the sander itself for the best results? In this case, we sanded after each coat at full speed with a 320-grit abrasive mesh disc (also shown). So, at least according to this manufacturer, medium to full speed is suitable for pretty much every sanding task. How fast should a random orbital sander spin? The primary purpose of a belt sander is to remove material fast. Is this normal? Bad Power Source Check the outlet connection, make sure the sander is plugged into the outlet. Consequently, the pad will spin in a circle very fast and when it meets a resisting point on the surface, it will remove it aggressively. Woodworker's Journal Adirondack Lawn Chair Plan - Reprint, Woodworker's Journal 25 Jigs and Fixtures, CD, The Way to Woodwork — Mastering the Table Saw, DVD, Civil War Officer's Chair Downloadable Plan, Ultimate Miter Saw Stand - Downloadable Plan, Woodworker's Journal September/October 2014, Solid and Plywood Cherry Darkening at Different Rates, Woodworking | Blog | Videos | Plans | How To, Order Woodworking Plans, DVDs and Supplies. I usually apply this convention, but I have tried reversing it or just using the same speed for all. This seems to spin much slower, but use more vibration to sand. My opinion is that once you get through sanding with 180-grit using a sander, it is time to move to hand sanding with 220-grit and higher. So we put the tools to the test -- both for between-coat scuffing and for rubbing out final coats. Bigger grit equates to less teeth and smaller grit to more teeth. To find answers, we needed a means of controlling downward force. We visually evaluated the effects on the sanding surface and used instruments to gauge stress on the tool. We focused our efforts on the most common wipe- and brush-on consumer finishes, including polyurethanes and poly-acrylics, and to a lesser extent, lacquers and oil blends. (To learn the results of our tests, pick up the October 2008 issue of WOOD magazine, and turn to page 60.). Deep swirls, uneven scratch patterns and visible scores -- like the marks shown here -- signal something's gone awry. The rotary sander also comes with a round pad but compared to a random orbital sander, the rotary sander doesn’t vibrate. The sanders ergonomic design reduces vibration and fatigue—making it easier to control. The bookmatched halves differ only in how finely each was sanded. Here, stain reveals the pattern left by an on-the-board sander start. The existence of unblended patterns can signify that you are moving the sander too quickly, applying pressure inconsistently, or using discs with uneven size abrasive grit. Under normal load, a sander motor must overcome the friction between the abrasive and the wood. An orbital sander is one of the easier power tools to use. Unlike orbit-sanders, which merely rotate in tiny circles, random orbital sanders not only rotate, but also add a slight wiggling spin to their motion, meaning that the rotations don’t have a definite pattern–hence are random–and the resulting sanding action is very fine and smooth. jambourgie. Other potential causes of swirls include using a sander with worn or damaged parts, and sanding wood that is too wet. Is the ETS not what I think a random orbital is? In this situation, the orbital sander will not spin at all. An orbital sander is a tool used for sanding wood and is commonly found in workshops and wood shops. We later applied a pre-stain conditioner and oil-based stain to our test boards, which made the sanding marks easier to observe and photograph. For testing purposes, we defined "normal load" as the weight of the sander plus our plywood yoke, shown, which served as a proxy for the weight of a hand. When you start one, if you don’t apply pressure right away to the pad, it starts spinning…fast. To test the effects of different linear sanding speeds on surface quality, one of our experiments utilized a stock feeder to move boards beneath a random orbit sander. Orbital Sander: Losing power with pressure. My background is in aerospace manufacturing. Do I start the sander on or off my workpiece? Orbital sanders are generally a lot more versatile than finishing sanders, although the latter is easier to control. Here, we used a stopwatch and optical tachometer to test the ramp-up of a sander motor, both under no-load conditions (shown) and with force applied. It moves in only one way. However, just like chess, it takes very little time to understand how it works, but it does take longer to master it. Bosch Power Tools – GET75-6N – Electric Orbital Sander, Polisher Being among the best random orbital sander, the Bosch power tool GET75-6N comes with an incredible 7.5 amp motor- This makes it perform at a no-load speed of 290 to 640 rpm. This issue arises when the oscillation bearing freezes up and can be solve by lubricating the engine bearings thoroughly. if you take that brake out, the sander will spin like an angle grinder. Rigid Orbital Sander Stops Spinning with Light Pressure. An orbital sander will spin too fast if the regulator stops working. But it allows the machine to properly do its work, and you will soon learn that by slowing down in that regard, you actually spend less time sanding overall. We worked with stearate-coated aluminum oxide sanding discs and newer mesh abrasives, in grits from 220 to 1500. Questions abound about the proper use of the random-orbit sander: How fast should I move it? (A small piece of reflective tape for this purpose is visible on the center wheel in the photo.) You can make better cuts by applying very less pressure on it. Maybe your resources can shine some light on this, or did manufacturers just give us variable speeds because we thought we should have it? We worked with side (raked) lighting, which is invaluable for spotting sanding and finishing flaws. To help ensure that differences we observed in samples were caused by grit changes and other sanding variables we wanted to test -- and not disparities in grain patterns, color or density between boards -- we made side-by-side comparisons using either bookmatched lumber or adjoining sections cut from the same board. It features a textured rubber over-mold for a more comfortable user grip in any orientation. We used this rig both freehand, and on a stand, paired with a stock feeder. To find out how our test results can help you finish your projects faster and better, pick up the October 2008 issue of WOOD magazine, and turn to page 60. This resistance increases with the coarseness of the sanding disc, the roughness of the wood, the sander's weight, and the pressure applied by the operator's hand. (We marked the sample number, 119, on the edge of the board for reference.). It ensures that the orbital action will work properly so the grit abrades the surface as efficiently as it can. Posted by 1 year ago. How should the speed and grit of paper be used on variable speed random orbit sanders? We produced these by applying extra pressure to the sander, which, among other things, hampers the normal movement of the free-spinning backing pad. Knowing the impact of load on the sander, and how it bears on both speed and motion, sheds light on some thorny finishing issues, including where to start the sander and how pressing down on the tool affects performance. I used the sander on surfaces with various curvature and using only little pressure, but the disk doesn't spin that fast. If one of these wires get cut when the regulator is on full speed, then you won’t be able to control the speed … It is put there to stop the spinning. When using abrasives to smooth a wooden surface the goal is to get a uniformly smooth result. Rob Johnstone: Ah, sanding, the root canal of woodworking. A well-maintained sander, used with sound technique and fresh abrasives, leaves a path that is thoroughly and evenly scuffed, with scratches of uniform depth. If for the above reasons the wire winding is burned, then the whole motor becomes useless. In metal machining, fewer cutter teeth equals lower rpm and more teeth will allow higher rpm. Here’s the symptoms. Unlike random orbital sanders, you do not need to buy the special sandpapers. 2. So after you’ve started with an appropriately coarse grit to quickly and effectively remove the surface blemishes, scratches and glue blobs, the next goal is to remove the scratch marks that you just installed on the wood’s surface with the 60-grit (40-grit?) I think the bigger issue, regardless of speed setting, is to not push down on the machine while sanding in an attempt to speed the process along. Grasp the sandpaper by any corner and pull it off of the orbital sander. The sander should be allowed to spin freely and under its own weight plus light hand pressure. I noticed the disc wasn't spinning really fast, maybe 200 RPM and I could actually stop it spinning with my hand or if I pushed too hard (but it would still be orbiting). Answering this question didn't require any special test equipment, just stacks and stacks of new sanding discs, an industrial-size carton of dust masks, and long days in the finishing room. The rectangular bottom also makes it easy to reach into corners. Some folks argue that random-orbit sanders are too aggressive for final finish work. Our tests confirmed that under heavy load -- such as that experienced when one bears down on the sander -- components like discs and hook-and-loop fasteners become prone to overheating and early failure. Nickjb, thanks. Close. The tools of this brand are exceptional, and speaking of their sanders is no … BUT, you have to turn the screws in the opposite direction you normally would. Chris Marshall: Dennis, as you point out, I’ve seen no real difference either in cutting efficiency by varying the speed of my sander relative to the coarseness of grit I’m using. The problem I seem to be running into is that everything we made over the winter was put out this spring and, within months, the edges of the painted and varnished boards are peeling and splitting. If you try and sand w/it in this condition it’ll scar whatever it touches. A: An orbital sander is a sanding machine that operates in a circle, by spinning the disc round. I do alot of vertical stuff, doors, cabinets, etc. Q. (When you remove all the 60-grit scratches, you move up and remove all the 80-grit scratches, and so on.) 3. Here are 10 tips to help you work faster, get a smooth, even surface and avoid those swirly scratches that don't show up until you apply your finish. Not spinning fast enough.