I've finally finished my new edge belt sander table. Because of the way I work, this kind of edge belt sander is one of the tools I rely on most, and I use it in almost all of my projects. I designed it with portability in mind, and so I can mount it on almost any kind of workbench.
The sanding belt is 915mm. It's the same one I use in the sander attached to my homemade lathe... Although they have some arrows indicating the recommended direction, most belts are reversible nowadays. As long as the belt is glued together with a piece of fiber in the back, and not overlapping, you shouldn't have any problem using them in reverse. This will help you get more use out of belts. For this type of belt sanders I usually use three grits of sanding belts, P80, P120 and P240.
I got my hands on a used motor in a scrapyard for only 30 euros. It's got 1 horsepower and 1370 revs, more than enough for this sander. Ideally we should aim for a belt speed of 350 meters per minute. To achieve that, the big traction wheel must run at 1000 revs per minute, which is why I lowered the motor's revolutions with pulleys and a V Belt.
If you have a different motor or want more belt speed, this is the formula to convert revolutions to radians: 1 rpm = 1 r/min = 2p rad/min = 2p/60 rad/s = 0,10471976 rad/s. Online converter:
Here you can calculate your pulleys:
And here you can download the plans:
Work table: 800 x 500mm
Total Dimensions: 850 x 500 x 230mm
This is the one I've been using for a couple of years. As you can see, it's simply a portable belt sander that's been rotated and attached to a table. The problem is it lacks power. The belt is short and the wheels, one of the parts I use most, are not easily accessible.
Placing and removing the sanding belt is quite easy. You only have to loosen or tighten this tensioner(second photo). I can calibrate the sanding belt by tightnening and loosening this screw(fourth photo).
In the end I decided to place this third wheel to calibrate the belt because I need the other two to be firmly locked and in proper alignment to avoid imperfections when operating it.
I've also developed this dust collection system. I can put it in line with the belt or rotate it to different positions. I'm going to perform some tests to show you how the sander works. First, at a 90 degree angle (second photo).
And here with pieces rotated to a 45 degree angle (third photo). This way I can sand the longer pieces edgewise, and the dust collection systems works the same way(fourth photo).
I'll try the sanding wheels on this electric guitar body. It's a great example because it has several kinds of curves. The big wheel will be most useful when sanding wide curves like the one you can see in the first photo.
The straight part of the sander is for this kind of curves(second photo), and the small wheel is for tight, hard-to-access curves like the one you can see in the third/fourth photos.
This is the SketchUp file you'll find in the plans. I will begin the construction with the base and the top of the sander. I cut all the necessary pieces with the table saw. I glue the printable template onto the plywood to mark the holes we need in the top. I can use those to mark the same holes on the base and make sure the wheels are aligned with the base
After screwing the top and base together temporarily, I drill the holes with this plunge router rig with a drill(third photo). With this straight bit, I mark the position of the bearings(fourth photo).
Having marked both pieces, I drill a hole for the bearings with a forstner drill bit. Now I can screw the base to these legs which will allow me to attach the sander to any bench with a few clamps(second photo).
I cut the contour of the top and after sanding the edges, I make a rebate for the belt tensioner. Now I'll make a hole for the motor with this plunge router. This kind of motor is attached to the front, making it ideal for this purpose. I finish the job with a jig saw.
I glue the printable template to cut the hole that will allow me to rotate the dust collection system, and do the same with the gap where the belt tensioner will be(first photo).
Now I'll build the sander's bigger traction wheel. I mark all the pieces and cut them with the jig saw. I mark all the pieces and cut them with the inverted jig saw. I drill all the parts with the column drill.
The lathe's sanding disc will come in handy to make them all perfectly round. I'll use the wheel's rod itself to function as axis like this(third photo). I make this little groove in the rod with an angle grinder(fourth photo).
Now I mark the position of the pieces on the rod and glue them together. When the glue is dry, I'll use this screw so that it matches the groove I made to lock the wheel to the rod(second photo).
I put in the bearings and and the sander's wheels in place. These are the aluminum ones I made in my previous article. I put in all the necessary washers and now I can attach the top, here it is better to use a locking nut. We needn't tighten the nut too much. Since it's self-locking, it won't come loose, putting less strain on the bearings.
The calibration of the sanding belt is more sensitive to the tilt of this wheel than to the tilt of the tensioner's wheel itself because it touches a larger part of the belt. It's very important that it be perfectly aligned so that the belt won't go off-center or move up and down. If necessary, we could also calibrate the belt by building a similar system to that of the tensioner wheel.
I cut the straight part that's in contact with the belt and screw it in. First the top and, after making sure it's properly aligned with the base, the bottom.
In the second pic you can see the belt tensioner. After verifying it's the right size, I drill holes for the two screws that will serve as rotation axis. I used a drill bit 1mm less than the diameter of the screw.
I test the tensioner and check that all the cylinders are square with the base. I'll test everything with a drill anchored to the traction wheel. This got me to think that this design could be adapted to be used with a drill, whether on the top or on the bottom.
in this second part I'm going to finish building my new belt sander. I will start with this metal plate that will go under the belt. I'll use this galvanized steel plate I had in my workshop(first pic). I'll cut it down to size with an angle grinder. I stick it onto the plywood like this with double-sided tape.
I'll also make the pulleys for the traction wheel and motor. After cutting the pieces we need for the motor pulley, I drill a hole with a bit with the same diameter as the shaft. I make a rebate for the slanted part of the motor shaft that will prevent the pulley from stopping while the motor rotates. I insert the pulley in the shaft being careful not to damage the motor, and attach a glued lid like this to lock the pulley in the shaft(fourth pic).
I've attached the motor to my workbench to make the pulleys. First I'll use a roughing gouge. Then, I'll use other smaller gouges to make a groove for the V belt. I'll double check every now and then to see whether the pulley is adjusted to the belt.
Now onto the traction wheel pulley. We could easily make it with a lathe, but I'll try to create it in the same way as the previous one. After fastening it to the motor shaft, I'll follow the same steps as before. Then all that's left is to make a hole for its shaft. It's not the best way to make it centered and balanced, but hopefully it'll work.
I put the motor in place and mark the positions of its screws. I make the holes and put the screws in to attach it to the base of the sander. I will also use washers and nuts.
This is the piece that will hold and lock the traction wheel pulley(third pic). I'll make a hole here with a bit whose diameter is half a millimeter smaller than the screw. I put the screw in place, the thread it will carve when inserting it will be enough to hold the pulley.
I apply glue and for safety reasons I'll add a couple of screws. After making sure this pulley is at the same height as the motor pulley, I tighten the screw to mark its position on the rod. I make a flat rebate for the screw right where the mark is. We could also make a small hole with a bit. Now I put the pulley back in place and finally tighten its screw.
I'll make the V belt's tensioning wheel out of a piece of plywood. First I make a hole for the bearing with the column drill. Then, with a hole saw I cut the wheel. I insert the bearing and with this piece of plywood and a screw that will act as axis, I will round off the wheel with the help of the sanding disc.(third pic).
Now I can install the belt to mark the position of the tensioning wheel. I think this much tension will be enough. I mark and drill a hole for a threaded insert. I'm going to use this piece of steel pipe as buffer, and now I can put the tensioning wheel in place.
It seems to be working correctly. The traction wheel pulley could be a little more balanced, but I think it will do the job just fine. Now that I can make the big wheel spin, it's a good time to smooth it out and make it line up perfectly with the base using P80 grit sandpaper stuck to a piece of plywood. I'll also use this makeshift wooden piece, having made sure it's at a 90 degree angle with the base, I start sanding the wheel until it's perfectly smooth.
Now would be a good time to apply some epoxy resin on all the wheels. This way the big one will have better grip between the wheel and the belt, and the aluminum ones will keep the belt in position while sanding. We could also glue some plastic material or use a bicycle tire tube instead of the epoxy.
This allen bolt will function as rotation axis for the piece that tightens the belt. I cut the pieces I need to the right size and shape them with the sanding disc. Using an angle grinder, I make a groove in this allen bolt. In it I will put a wooden screw to lock the plywood pieces to the allen bolt.(second pic).
Since I'm using a used motor, I had to make a small compartment to fit its capacitors. I took advantage of this gap in the bottom of the base. I've also installed a switch to turn on the sander comfortably from the front. I screw the rest of the frame pieces in place.(fourth pic).
For the top we could use 9mm thick plywood and glue a formica sheet onto it. It would work perfectly. I happened to come across this HPL panel piece in a nearby carpenter's store. Just the thing I needed!
I need to make a rebate to attach it to the sander, so I make one with the table saw and the jig saw. Also with the sander itself I will finish sanding the gap. I make some holes and now I can screw in the panel to the base of the sander(fourth pic).
Now all that's left to do is make the dust collection system. I cut all the pieces and after making sure they're the right size, I screw them together. I've marked the circumference of the vacuum tube, although other tube diameters could be used. The dust collection system must be securely built and well aligned. Otherwise, when pushing the handle against the table we could strain the wheel's threaded rod and decalibrate the sanding belt.
As always, I make a handle with a hole saw to hold the dust collection system. I mark the position of the hole on the base of the sander. If you want to use plywood you will have to use a threaded insert here. In this case, I won't need it because the HPL panel is easy to thread.(fourth pic).
With the jig saw, I finish machining the groove that will allow me to rotate the dust collection system and my new sander is finally complete! I'm sure it will be very useful in many of my future projects...