Builing the bandsaw
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Building the bandsaw frame
 | The basic bandsaw frame consists of a C shaped wooden beam laminated together from spruce boards. The idea started when I was thinking about how I could make my homemade bandsaw stiffer. I figured I could do better if I made the beam arch right over to where the wheel mounts are. I first thought of finger jointing some beams together into a C-shape using my screw advance box joint jig. but that would make it very difficult for anybody to reproduce the project.My second idea was to form the beam by laminating individual boards together into a beam. By overlapping the boards at the corners and joints, I could create some very large joint surfaces. |
 | The beam was built up one layer at a time. The photo at left shows the first full layer being assembled. I started with the front-most layer. The column at the left has one extra leyron the front. I glued the parts of the first full layer onto that piece. |
 | A detailed view of the first layer after the glue has dried, with boards for the second layer ready to glue on. |
 | I made a 1:1 printout of the plan for the frame over multiple sheets of paper. This was very handy for checking the dimensions of the pieces I cut - it was just a matter of laying them on the sheet.The diagonal grid on the printout is not part of the drawing. I added that grid to help me line up the pages when gluing them together. I'd found that with my gear generator program that the diagonal grids were extremely useful for accurately lining up sheets of a printout. |
 | I ended up using all of my small clamps every time I glued up a layer. Gluing up the frame extended over the course of a day and a half, as I'd glue on a new layer, and then do something else while the glue dried.An alternative would be to screw and glue the frame together instead of clamps and glue. However, you will have to drill some holes in the frame after assembling it, and you might drill into some of the screws. So if you do use screws because you don't have enough clamps, take the screws out again before adding the next layer. |
 | More layers glued up. Note how the diagonal bracing extends into the frame. The diagonal bracing extends into the column, and into the horizontal layers in alternate layers so it forms a sort of triple mortise and tenon joint on either end. |
 | I didn't get the pieces perfectly aligned, so after the frame was cleaned up, I used a hand plane and a spoke shave to trim the edges so that the boards were all flush with each other. Much of the trimming was cosmetic, though in some areas, I was able to correct for slight inaccuracies with planing. |
 | I ended up with a slight twist in the frame. I hadn't thought of checking that the frame was all flat as I glued it up. Looking down the top of the frame, you can see the bottom horizontal part of the frame where the arrows point. Note that it sticks out more on the left than on the right. It's not entirely parallel to the top edge.To avoid this problem, make some spacer blocks to hold every part of the frame the same height above your workbench (so you can still get clamps under it), and make sure it rests fully against the workbench as you glue it. |
 | I could easily have compensated for the twist in the frame by mounting the wheels at a slight angle. But I wanted to be able to use the front faces of the frame as a reference surface when aligning other parts. So I used a power planer to shave a four millimeter thick wedge off the lower horizontal. After removing the bulk of the material, I used a hand plane to smooth it out. |
 | Lots of checking for squareness. Here I'm checking that the top of the bottom horizontal of the frame is at a right angle to the vertical. The table will mount to this part of the frame, so the surface needs to be square.I also made sure the underside of the bottom horizontal was square, as that is where the wheel mount goes. |
 | The completed frame is quite light, under 30 pounds of weight. When I measured how much the fame flexed from tensioning the blade, I found that it was stiffer than the frame on my cast iron bandsaw.This may seem a little surprising, but consider the following figures I gathered from the internet:
| Material | Young's modulus |
|---|
| Steel | 200 GPA |
|---|
| Cast iron | 80 GPA |
|---|
| Pine | 9 GPA (along the grain) |
|---|
Young's modulus is a measure of stiffness for a material. The figures for cast iron can vary, and for wood they can vary a lot. Overall though, steel is 22 times stiffer than wood. But cast iron is only nine times stiffer than wood. So a member with nine times the cross sectional area of cast iron will be as stiff. Making the beam wider also helps, and the wooden beam is a fair bit wider than my cast iron bandsaw's frame.
Don't use plywood
Please note that the figures above are for wood strength and stiffness along the grain. Wood tends to be much weaker across the grain. If you were to make the frame out of plywood, half the wood grain would be perpendicular to the direction of force, which would result in a frame only half as strong and half as stiff. Do not use MDF for the frame, as it will sag under load. Any evergreen soft wood (other than balsa) should be adequate for the frame. You can also use hardwood, resulting in a stronger frame, but it will be much heavier. |
Making the bandsaw wheels
 | I start making the wheels by drawing some circles slightly larger than my wheels would be on some plywood using a set of trammel points (beam compass).For this bandsaw, I wanted to see if it was possible to build it with very inexpensive materials, so I only used regular plywood, not the nice baltic birch plywood. |
 | The best tool for cutting out bandsaw wheels is, ironically, another bandsaw. But if you don't already have a bandsaw, a jigsaw will do the job.There is a clever table saw trick of slowly turning the wheel against the spinning blade to cut out exact circles. Numerous people have pointed out this trick as an "improvement" to me. I am familiar with this technique, but I don't think it's a good idea for the bandsaw wheels, which is why I didn't use it here. The difficulty is with getting the wheels to run sufficiently true. The technique described in this article ensures the wheels run true with the bearings mounted. |
 | A jigsaw can cause a lot of tearout. Some of this tearout can be avoided by scoring along the compass line with a knife before cutting. |
 | Cutting outside the score line, you can see how the tearout stopped where I scored the wood. |
 | I glued three pieces of plywood together. I had some scavenged plywood that was 12 mm thick, and added another layer 5 mm thick between them. |
 | I used lots of clamps to glue up the wheels. I wanted to be sure I had a good solid glue joint, especially around the edges. |
 | I bought some ball bearings for my 1" shaft. The outside diameter of the ball bearings were 52 millimeters, which falls in between the sizes available for large Forstner bits in fractional inch sizes. A circle cutter could be used to cut holes of just the right diameter. I meant to buy one at Lee Valley Tools, but when I got there, the store had just closed for the day. So I made my own crude circle cutter instead.
The description for the one on the Lee Valley Tools website says that it has a center drill to prevent mishaps on cutthrough. The one I made didn't have a center drill, and sure enough, as soon as I cut through, the center section jammed with my cutter, throwing everything out of adjustment. So to avoid this mishap, I used the next smaller drill size and drilled out all the wood from the center section. I then used my circle cutter to enlarge the hole to the desired size.
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 | The cutter part of my circle cutter's was just a carriage bolt that I ground square on one end. It cut surprisingly well.Unfortunately, adjusting the size of circle to cut on my homemade circle cutter was rather difficult. It was just about impossible to make small adjustments. So I kept adjusting it and testing it until it cut circles that were about 51.6 mm in diameter. At that point, I figured I was close enough.
I have since found a circle cutter for only $8, and, considering the trouble I went through without one, I must say that a circle cutter would be a good investment. |
 | I used a sanding drum in my drill press to open up the holes just a tiny bit more so that I'd achieve a press fit with my ball bearings. |
 | I used a large block of wood with a slight indentation drilled into the end of it to help drive the bearings into my flange blocks. That way, I'd be applying force to the outside ring of the bearings. |
 | An arbor press would have been handy to press the bearings in, but driving them in with a mallet worked too.The bearing's fit into the flanges needs to be very tight - tight enough that it's impossible to push the bearing into the block by standing on it. When part of the bandsaw wheel, with 100 pounds of tenion on the bandsaw, there will be 200 pounds (about 100 kg) of force on the bearings. This force alternates in direction with respect to the wheel as the wheel turns. So imagine the bearing being yanked back and forth with 200 pounds of force ten times per second for many hours continuously. If it's not in there very tight, it will work it's way loose eventually. |
 | Four bearing flanges ready to install.You might wonder, why go through all that trouble instead of just buying some flange bearings? The reason is that I can't glue the steel flange bearings to the wood very well, and on my previous bandsaw I ran into problems with that and eventually replaced the steel flanges with wooden flanges that I glued in place. |
 | I drilled a 1 1/8" (28 mm) hole through the main wheel disk. I then glued one flange to the wheels. Looking through the hole in the wheels, I made sure that my flange was aligned with the hole.I clamped one of my steel shafts to my workbench to serve as a "truing stand". I put the wheel on this shaft, and clamped the other flange to the wheel and made sure it ran reasonably true. After that, I removed the flange, added glue, and loosely clamped it on again. |
 | I reduced any wobble of the wheel as much as possible by hitting the wheel with a mallet before the glue dried.Once I was satisfied with the trueness, I tightened up the two clamps and added two more clamps to press the flange block against the wheel. |
 | I shaped the rims of the wheels by using the wheels like a lathe.With the wheel turning on its own bearings, any eccentricity I had with how I mounted them got cut away as I turned the wheels down to their final size.
I did encounter a few voids in the plywood that I had to fill. I didn't bother filling small voids near the edges. But the middle of the wheel, where the blade normally runs, had to be free of voids.
Some readers have used a clever table saw trick to shape the wheels perfectly round, even cutting a 5 degree bevel from both sides to shape the crown of the wheel. However, even if you used such a technique, to get the wheel to truly run true once mounted on the bearings you still need to turn them with a chisel to do the final truing. And if you do turn them with a chisel, the table saw trick becomes redundant. Which is why I don't recommend the table saw trick for shaping the wheels. |
 | I shaped the rim of the wheel to have a "crown" on it. That is to say, the center of the outside rim surface has the largest diameter, and dropping off about 5 degrees towards either edge. This puts the two sides at about a 10 degree angle from each other. |
 | I spun up my wheels by screwing a temporary pulley to them. The big hole in the center of this pulley fits around the flanges. Four screws mount the pulley to the side of the wheel.The temporary pulley doesn't have to be that accurate. I just left the V-belt a little slack to compensate.
You can make such a temporary pulley by sandwiching three layers of plywood together. Or, if you are adventurous, you can take a piece of 3/4" (19 mm) plywood and cut a groove around the circumference on the table saw. I didn't bother making the groove V-shaped. A square groove worked well enough for what I needed. |
 | The bottom wheel in this design spins on a fixed shaft, just like the top wheel does. The advantage of this design over a spinning shaft with a separate pulley is that there is no need to couple wheels to the shaft. Also, the force from the blade tension is evenly spread over two bearings. |
 | The lower wheel of the bandsaw has the drive pulley attached to it. I turned the groove in the drive pulley by spinning it with my temporary pulley attached to the other side of the wheel.I put some spacers in between the wheel and the pulley to give me a bit of extra space to work with my turning tools. You can see the gap between the bandsaw wheel and the pulley I'm just starting to turn. But the spacers were probably a bad idea because after I took them out, I had a hard time getting the pulley centered on the wheel again. |
 | Checking the fit of the V-belt. I took a V-belt and flipped it inside out so that I could hold it against the pulley to see how it fit. The photo at left is when I decided it fit well enough. |
 |  After turning the wheels, I gave them two coats of varnish. The next step was to balance the wheels. As I had done with my previous bandsaw, I used two small rollerblade bearings inside my main bearings for balancing. The reason for that is that the small rollerblade bearings turn much more easily than my main bearings, so that even a small eccentricity was enough to pull the wheel's heavy side down with gravity.The small bearings were just loosely slid onto a screwdriver. The small bearings (7/8" outer diameter) in turn fit loosely inside my main bearings. But because the inside of my main bearings is round, they'd just roll inside them, so I could still count on my wheels eventually turning heavy side down by gravity.
I had to drill quite a bit out of this wheel to bring it into balance. Cheap plywood tends to require more balancing than high quality plywood. |
 | As with my previous bandsaw, I used bicycle inner tubes for the tires. A 14" inner tube works best for the 16" wheels. I cut the inner tube open by cutting the valve off with scissors, then cutting around the tube from the valve back to the valve. Basically, my cut followed the line that would normally be against the center of the bicycle rim. |
 | Inner tubes often have this white powder on the inside, probably from some part of the manufacturing process to prevent the rubber from sticking together. That powder needs to be removed so that the rubber will "stick" to the rim. I don't glue the tube onto the rim, but the natural stickiness of the rubber is enough to keep it from sliding, even over time. Basically, rubber pressed against a smooth surface will over time stick to it. This is why I varnished the rim of my wheel.The tube is shorter than the rim's circumference, so it's always pressed against the rim because it's stretched around.
I didn't think just relying on the natural stickiness or the rubber would be enough to keep it in place, but so far I haven't encountered any problems on either of my homemade bandsaws, so it seems to be ok. |
Building the wheel mounts
 | The bottom wheel mount is relatively simple. It's just a block of hardwood bolted onto the frame with some 1/4" x 5" wood screws. Making that block out of soft wood would have been strong enough as well.My original thought was to extend the frame further down and drill the hole directly into the frame. But the problem with that approach is that if you don't get the alignment exactly right, there's no way to fix it. So I opted to mount the lower shaft into a separate block of wood.
The tricky part is drilling the 1" hole all the way through the block. Commonly available forstner bits are only long enough to drill about a 7.5 cm (3") deep hole, but to drill through this block requires depth of about 4" (10 cm). What I ended up doing is drilling from one side as deep as the drill will go, then mounting the drill only part way into the chuck, and drilling a little deeper. Next, I took an extra length 1/8" (3 mm) drill and drilled from the point in the bottom of my forstner bit hole through to the other side. I then used that 1/8" (3 mm) pilot hole to guide my forstner bit when I drilled from the other side. The holes aligned perfectly.
If you find your holes not aligning perfectly, you can carve them out a bit by pushing the stock sideways as you raise and lower the spinning forstner bit in the hole. |
 | The wheel with its pressed in bearings slides loosely on the shaft. To keep the wheel from sliding off the front, I drilled and tapped a #12 machine screw hole into the front of the shaft. A screw and large washer keep the wheels from sliding off. If you don't have machine screw taps, you can make your shafts about 1" longer and put a clamp on it (see next picture). You will have to leave a hole in your top and bottom cover to allow for this though. |
 | To keep the lower shaft from sliding forward out of its mounting block, I made a clamp to put on the back of the shaft. A wood screw tightens the clamp onto the shaft. |
 | When I originally got my shaft and bearings, I found it was just about impossible to get the bearings onto the shaft. As best as I could measure, both the shaft and the bearings were exactly 1" in diameter. But to slide the bearings onto the shaft without having to press them on, the shaft needs to be just a hair smaller than the hole in the bearings.I ended up mounting the metal shaft in my wood lathe, and holding a file to it to shave it down by about 0.001" (.025 mm). This allowed the bearings to slide on and off the shaft easily. |
 | I had to make a small wooden spacer to space the lower wheel at the correct distance from the frame. The spacer goes between the lower mounting block and the back bearing in the wheel. I made the spacer by drilling a 1" hole in a piece of wood and then cutting that piece of wood to size. I cut mine round on another bandsaw, but if you don't already have a bandsaw, it's ok to leave the outside square. |
 | Two L-shaped pieces of hardwood are screwed to the posts sticking out of the top of the bandsaw. These hold the frame that slides between them. This sliding up and down is used to apply tension and adjust for slightly different blade lengths.I put some UHMW tape on the surfaces that the frame slides into after I finished my saw. If you do use UHMW tape, don't put it in right away. Get the saw tuned up first, so that you can put the tape on your final surfaces. |
 | This is the top frame. I used my screw advance box joint jig to join the corners of it. The corners need to be very sturdy. With, for example, 150 pounds of blade tension, the tensioning bolt has to pull twice that amount of force on the frame. So the corners of the frame need to be very sturdy.Alternately, you could also make this frame out of baltic birch plywood (the kind that is layers of hardwood birch throughout). Ordinary plywood probably wouldn't be strong enough. |
 | Or you could make it out of four pieces of solid hardwood and put four splines into each corner.The key to doing this is to glue this frame together before cutting the slots for the splines. After the glue is dry, use a tenon jig and cut the spline slots into the frame. Then make thin hardwood splines to fit into the corners. |
 | The frame should slide reasonably easily inside the guides at the top.On my saw, I found I had a little bit of alignment error, so I had to put one of the shims on the front to angle the frame the right way. |
 | A solid block of hardwood slides into the frame. The block of hardwood has a lip on the front side of it, just below the shaft. This lip hooks into the rail on the frame that it sits in.With the blade tensioned, there is a lot of downward force on the shaft, which in turn will push the block down and try to turn it clockwise (as from the vantage point of the photo). This causes the lip on the bottom to be pressed into the slot on the frame, and the tracking adjustment screw at the top to be pressed against the frame |
 | The tracking knob is held in the block of wood with a T-nut that is sunk into the front of the block. |
 | The tracking knob itself is just a regular 3/8" bolt, with the head pressed into a block of wood. |
 | Two drywall screws (removed in this photo) attach the block of wood to the frame. These screws are meant to just hold the block in place when no blade tension is applied. Once the blade is tensioned, the block is firmly pressed into the slot from the force of the blade tension. There is no risk of the block slipping out of the slot, seeing that the block also wants to rotate forward, which pushes the front lip against the frame. |
 | This is the whole top wheel mount, without the wheel, as seen from the front. The "tension spring" consists of three thin strips of wood across the top of the frame. These are meant to bend and act as a spring as tension is increased |
 | The thin strips of wood are just hardwood strips. Some species, such as ash, oak or hickory would work best. But other hardwoods, such as birch or maple are fine as well. Don't use an exotic hardwood for the springs, as those don't flex very well. |
 | The crank threads onto the top of the tensioning bolt. The threads of the crank are a "coupler nut", which is essentially a nut that is about 1.5" (4 cm) deep. The coupler nut is pressed into a hexagonal cutout in the crank. |
 | I cut the hexagonal cutout on my bandsaw. You can just use a regular nut and a wrench to tension up your bandsaw, so that you can use your bandsaw to make this part. |
 | A wood screw across the end of the crank helps to secure the coupler nut in place.The crank handle is just a piece of 3/4" (18 mm) dowel screwed on. I used a 3" long wood screw and cut the end off of it. That way, the dowel is mostly around the thread-less shank of the screw, so that the dowel turns loosely on the screw. |
Making the blade guides
One blade guide option would have been to buy after market blade guides. But after market guides tend to be quite expensive, and that would undermine the whole rationale for building a bandsaw.
So to keep costs down, the blade guides are made out of wood. I used some very hard African Bocote hardwood offcuts for the guide blocks. Those only cost me about a dollar. But Maple could also be used.
 | I was originally going to use Lignum Vitae, the hardest of the hardwoods, but when I went through my box of exotic offcuts, I tried rubbing each one on my cast iron table saw to see how slippery they were, and the bocote slid the easiest, so I used that instead.
But you don't need to get Bocote. Any hardwood will do, the heavier the better. |
 | This drawing shows how the blade guides go together. The top and bottom blade guides are nearly identical in design. |
 | The thrust bearing is mounted such that the blade runs against the outside of the bearing, rather than on the side as it does on cheap bandsaw guides. I used a 1" forstner bit to cut the clearance for the thrust bearing in the main mounting block. |
 | I also had to drill a hole in the end of the mounting block to leave clearance for the ends of the guide block mounting screws. |
 | A small block of wood with two T-nuts in it is screwed across the front of the main block of the guide assembly. I was originally hoping to join this block with some sort of wood joint, but there is not enough room between the two T-nuts in the back of this block, so I used two long drywall screws instead. |
 | The T-nuts are recessed into the back of this block. I pre-drilled holes for the prongs of the T-nuts to avoid the risk of splitting the wood on driving the T-nuts in.I marked the location of the prong holes by inserting the t-nut in place, and tapping it in so that the prongs would leave divots in the wood. I then drilled holes just slightly smaller than the T-nut's prongs where the divots were |
 | A slot in the main mounting block allows the guide assembly to move forward and back. I made that slot by drilling a series of holes with a brad point bit and then cleaning the space out in between to form a slot.With so much of the block cut away, to be on the safe side, I put two 1.5" drywall screws into the block. The holes for these screws is sized such that the thread engages along the whole length. The screws don't hold anything to anything else. They are just there to ensure that the block will not split apart. |
 | Next, I held the blade guide onto the guide bar in its rear-most position, and pushed a 5/16" drill down to mark the center of the end of the slot (I didn't spin up the drill press for this) |
 | The point of the drill made a divot in the vertical guide bar. I drilled a 1/4"(6 mm) hole where the divot was for my 1/4" carriage bolt. |
 | This shows the completed top blade guide. I used these large headed "knock down" screws from The Home Depot to hold the bearing blocks in place. I always think of these as "Ikea screws", because they are just like the screws that hold so much of their furniture together. But don't get the screws from Ikea. Their screws tend to be metric, so unless your T-nuts are also metric, they won't fit.Also note how the thrust bearing is held on. I prefer to be able to tighten the screw from the right, but this means I have to hold the nut on the bearing with my fingers as I tighten it. |
 | The bottom guide is identical in the method of construction, though the main body of it has slightly different dimensions. |
 | The bottom guide screws into a T-nut that in turn is screwed into the trunion support beam.A threaded insert might be more convenient, but I didn't think of it at the time, and this way, there's one less extra screw type you have to shop for. |
 | A t-nut slides in the slot that the thrust bearing can be moved forward and back on. I flattened all but one of the prongs of this T-nut. |
 | The one prong of the T-nut that I didn't flatten slides in the slot and keeps the nut from spinning as its tightened (click image to enlarge) |
 | Because of space constraints, the blade guard above the top blade guide is made out of sheet metal.The blade guide needs to be fairly precise. It needs to be able to fit around the top wheel, yet also fit inside the enclosure. |
 | The best source of metal for this is to cut it out of an old PC case with an angle grinder, although a hacksaw could also be used.When using an angle grinder to cut sheet metal, do not cut through the metal right away. Instead, just go back and forth over the line of cut until you break through. The advantage of this approach is that as long as you are only cutting on the surface, all the sparks get thrown off in the same direction. Once you plunge cut through, sparks get thrown every which way, and you are more likely to get hit by hot sparks. |
 | I cut an L-shaped section out of the PC case. A second bend turned this into a C-channel.A metal brake would be ideal for the job, but I don't have one, so I always use my vise. A block of hardwood allows me to spread the hammer blows across the width of the vise. But with the width of the vise much less than the length of my channel, I only bent one section by about 30 degrees, then moved the piece to bend more of it, going back and forth for each additional 30 degrees in bend. |
 | After bending the C-channel, I drilled three holes for the mounting screws. The holes are about 1/8" (3 mm). I then used just the point of a larger 5/16" (8 mm) drill to shape a countersink for the screws. |
 | Before cutting the notch to fit the guide bar, it's important to know exactly where the blade will go. Use a fairly wide bandsaw blade, put it on the wheels and tighten it up firmly. Then use the edge of the blade as a guide to draw a pencil line on either side of the blade.Be sure to hold the pencil perpendicular to the frame (when seen from above). The middle of the two lines marked from either side will now exactly denote the line that the blade follows along. |
 | Next we need to jig something up to cut out the notch where the blade guide column fits into. The cut needs to be 25 mm to the left of where the blade runs. Clamp a board to the frame to act as a guide for a hand held circular saw, and clamp another board to that to act as a fence to push the shoe of the saw against.Align this to the pencil marks you made for where the blade goes on the top and bottom. |
 | Set the circular saw to cut 29 mm deep into the frame, and make a series of cuts to clear away most of the material. Only the last cut needs to be against the guide, the other cuts are just to hog out the material. |
 | The finished hogged out cut. |
 | Use one of those bolts that is normally used to attach table legs, and attach it into the end of the frame. If you don't have one of those bolts, you can drill a hole slightly smaller than the major diameter of a piece of threaded rod and just screw the screw the rod into the wood. For good measure, you can fill the hole with wood glue before doing this.If the screw has no place to grab onto, you can put two nuts on the threads, tighten them against each other, and then use that to tighten the screw into the hole. |
 | I cut the block that screws on there from a solid block of hardwood. I actually cut my block by putting it upright on my other homemade bandsaw. |
 | You can also cut it on the table saw by hogging the material out with a series of cuts, then making a beveled cut on the inside (careful with that - that step is slightly risky). Clamping it to a tenon jig for that final cut might be a good idea.The safest way to make it would be to glue take a square piece of 3/4" plywood and gluing a triangular section to one edge, and two square sections to the other. |
Building the trunions and table
 | The trunions are the half-round arches that allow the table to tilt in such a way that the blade slot on the top of the table doesn't move sideways.It would be easier to make the table tilt by mounting it to hinges on the bottom of the table, but then the blade slot would move side to side with table tilt. |
 | It was tempting to paste the 1:1 template from the plans onto the piece of wood I cut the trunions out of. But the shape consists of just two arcs, so it was easier to use a compass to draw the shape onto the boards. |
 | You need a bandsaw to do a good job cutting out the trunions. If you don't have another bandsaw, it's best to set up some sort of temporary table on your bandsaw so that you can use your unfinished saw to cut out the trunions. |
 | The trunions are made of three layers of wood. By layering making them out of three layers, the whole problem of how to cut that slot in the middle is eliminated. Also, the grain for the pieces glued in runs tangentially to the curvature, so those pieces also help reinforce the trunions at the ends, seeing that the wood is nearly cross grain at the end of the trunion arches.If you have any baltic birch plywood (the type that is birch throughout), that would be a good material to use for the trunions as well.
I glued the trunions together in two steps. First I glued the middle pieces onto one of the side pieces, and after that I glued on the third layer. |
 | Getting the alignment exactly right when gluing the final layer on is critical. I used a square and a flat table to make sure everything was aligned correctly.After that I used the right angle table on my belt sander to trim the two sides exactly flush. |
 | The carriage bolts that go through the trunions have a piece of wood around the head that fits into the inside of the trunions. I used a template from my 1:1 plans to trace the shape of this onto the end grain of a block of hardwood 3.8 cm long.I then used my bandsaw to cut that shape out. Again, if you don't have another bandsaw to use, rig up a temporary table on the bandsaw you are building to use it to cut this piece out. |
 | The block is then prepared to receive the head of a carriage bolt. First drill a larger hole, the size of the carriage bolt head, followed by a 5/16" hole. This hole is then filed out to square to mate with the square part of the carriage bolt head. |
 | The trunions are screwed onto the sub-layer of the table. The sub layer helps reinforce the table, helping it keep flat even though it is weakened by the slot for getting the blade in and out.Although these layers need to be glued together eventually, it's best to only screw them together initially so that everything can be taken apart again for fitting and adjustment.
In this photo, I'm using the table sub-layer to help hold the trunions while I'm drilling a 45 degree hole for a second set of mounting screws.
Drills tend to drift sideways as they enter the wood. Pre punch the hole locations with an awl, Push the drill as far into the drill chuck as it will go, run it fast, and approach the hole very slowly to minimize this. |
 | With the 45-degree holes drilled in the trunions, the sub-table is screwed to the bottom of the table. Then, using a smaller drill, use the holes in the trunions as a guide to drill the pilot holes for the screws into the table.The trunions themselves will not get glued in place, but the two 45-degree screws, plus the two screws seen from the end should be enough to hold the table securely onto the trunions. |
 | The front trunion support is a little bit complicated. It needs to reach through below the table, above the wheel, and to the left of the blade. It would be nice to support the front trunion from the right or from directly below, but that would make it impossible to get the bandsaw blades in and out.On a lot of commercial bandsaws, the front trunion support can be quite flimsy on account of this. On this bandsaw design, I used a large piece of hardwood to reach forward from the frame. |
 | The front trunion support is attached to the end of the beam reaching forward with five 3/8" (10 mm) dowels. |
 | Getting the holes for the dowels drilled accurately is critical. A good way to get them accurate is to use a marking gauge to scratch lines where they need to go, then punching the intersections with an awl, and then using a 3/8" ( 10 mm) brad point drill to drill the holes. The punched awl holes help guide the point of the brad point drill in place before the drill actually starts drilling. This makes for sufficient accuracy for the dowel joint. |
 | To transfer the location of the mounting hole for the trunion support beam, I put the screws in the holes and just tapped them in with a hammer to make divots in the frame.Laterally, the trunion support beam needs to be positioned so that the center of the arches of the trunion supports are at the same side position as where the blade will go. If you followed the plans exactly, that means the right edge of the trunion support beam will be 14 mm from where the blade will go, measuring to the edge of the beam, not the notch that gets cut into the beam. I hadn't yet cut the clearance notch for the blade guides in the support beam yet when I took this photo. In fact, the whole trunion support beam is only dry fit with the trunion supports on either end. I only glued it all together once I was sure it all worked out. |
 | Here's my four divots for where the screw holes need to go. I then drilled the holes out to 3/16 (4.5 mm)"The blue clamp is in place because I was gluing on a block of wood to the front of the frame to give more support for the trunions support beam at the same time. |
 | To figure out where the holes for the trunion clamping bolts go, I put the sub-table with its trunion halves on to the support and tilted it to 45-degrees. I then inserted a pencil into the slot of the trunions and marked the trunions with it. This tells me how far to the right I can put my bolts and still be able to tilt the table 45-degrees to the right.Note that the pencil is not vertical. This is intentional. The table tilts 45 degrees right but not at all to the left, so placing the bolts at a slight angle makes more sense. |
 | Drilling the hole for the trunion. Make sure that you drill perpendicular to the surface of the arc. |
 | Finally, a notch needs to be cut into the side of the trunion support beam to accommodate the blade guides. Space around the blade guides is fairly tight. In fact, I found the blade guide blocks hitting the bottom of the table when tilted it 45 degrees, and had to cut a corner off my right guide block (I did that after I took the photo). I also had to cut a 45 degree chamfer on the blade guide mount to keep it from hitting the sub-table. |
 | this shows the sub-table, tilted 45 degrees. The guide blocks are removed in this photo.I used a recyled piece of wood for the sub-table, which just happened to have a slot along the length of it. Ignore that. |
 | I made the saw table from a hardwood panel that has these plywood layers on either side. It came from some discarded furniture. It's a good material for making jigs.If you make the table out of plywood, it's preferable to use the birch plywood that has the birch layers throughout, although conventional good quality plywood with a hardwood veneer should do as well.
I have the outline of the cutout for my insert marked in this photo.
The hole in the table itself was cut with the bandsaw. The relief cut, leading off to the bottom right is for getting the blade in and out of the saw. I cut that with a table saw to make sure it's straight and wide enough for any bandsaw blade. |
 | In preparation for routing out the blade insert, I measured the distance from the edge of my router bit to the edge of the base. On this router with this bit,, it's exactly seven centimeters. |
 | Rather than make a whole routing jig for cutting the cutout, I just clamped a square to my table to serve as one side of the guide for routing out one side of the insert clearance at a time. |
 | I moved the square to one side at a time, and routed only one side at a time, being careful not to overshoot in the corners. After routing, I used a chisel to square out the corners. |
 | with a rectangular cutout in the table, the insert itself is also just rectangular. The really clever thing about this is that all I have to do is take a piece of plywood of the right thickness, and slide it into place while the saw is running. This creates a zero clearance insert for my bandsaw. Really, it puzzles me why bandsaw manufacturers haven't thought of this trick.Be careful with zero clearance inserts though - they will bend the blade if you forget to remove them before tilting the table.
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Building the bandsaw enclosure
Top cover
 | The top cover for the bandsaw slides on from above. That way, I didn't have to worry about latches for holding the cover closed or rattling from a lid that wasn't securely held in place. |
 | The cover is held in place by four pegs that insert into holes on the bandsaw frame. The pegs are tapered to make it easier for them to hit the holes, but getting the cover on does take a minor amount of practice to get the pins to hit the holes right away. |
 | There is a fifth peg at the bottom left of the cover which inserts into a hole in part of the bottom cover assembly. |
 | A better view of the four blocks with the pegs on them. |
 | The right side of the top cover is open on the back to allow for room for the guide bar column. The guide bar column on this saw is nearer to the blade than it is on a lot of other bandsaws, which is why the cover needs a cutout for it. But the top cover is not intended as a dust containing housing, so the opening doesn't matter much. |
 | Here's the top cover removed. Note the part on the bottom right of the photo. This is the guard for the blade on the left side of the saw. It's not possible to slide the guard on straight from the top because that blade guard needs to be put around the blade, which isn't possible if it's coming straight down. The cover is instead pushed against the saw at about the height where the center of the top shaft is at the bottom edge of the top cover, and then slid down until the pegs hit the holes.I glued a few extra bits of plywood to the back of the cover's front, figuring that might make the saw quieter. It didn't make a difference, so those bits are omitted from the plans. |
 | I made the top cover by gluing the horizontal and vertical pieces to the enclosure (two of the three pieces clamped on in the photo). |
 | Next I held the two corner pieces on top of the corners and marked the overlap from the bottom (although this photo actually shows it from the top), and cut that angle out with my bandsaw. I then glued these pieces on. |
 | I tapered the pegs I used on my belt sander. It's tricky enough to get them to align with all the holes at once. Tapering them makes it easier. |
 | Before inserting the pegs into the cover parts, I clamped the cover onto the saw where it should go and then marked where the holes should be on the frame. There is a pencil tick mark on the cover's piece which indicates the lateral position of the peg hole on the cover. I'm transferring this position onto the frame. All the pegs are the same distance from the cover, so I knew to drill the holes that same distance from the front edge of the frame. |
Bottom cover
The top cover's primary purposes are safety and aesthetics. The bottom cover, however, also serves as a dust control mechanism and a stand. The idea is that the bottom wheel is in a mostly enclosed space, so that the sawdust will eventually fall out the bottom of that enclosure into some sort of box or stand. The saw is meant to be mounted over a box to catch the sawdust. Ideally, the stand would be a box with a big hole just below the bottom cover so that the dust will all fall out of the saw and into that box. I have not at this point built a dedicated stand for the saw, so I currently have it elevated on some pieces of 2x4 and a box below it to catch the sawdust.
 | This photo shows the left side of the bottom cover. It's cut from a piece of 2x4. Without those pieces, and without attaching it to some sort of base, the saw is actually fairly tippy because so much of the saw's weight is forward of the frame.The left side of the cover has to make allowances for the drive belt, whereas the right side is just a sold piece straight down. |
 | The front cover hooks onto extensions of the stand. This makes it easy to completely remove the cover and eliminates the need for hinges or other hardware. |
 | At the top, the cover is held closed by one of these hooks. Those hooks are by far the cheapest option for holding the cover shut. In a pinch, you could even bend one out of thick wire, although this particular hook is bought from a store. It's normally used with two eye bolts instead of screws. |
 | I made another cover piece to go around the blade guides. This really helps to contain the dust to inside the saw so that most of it will fall out the bottom.This part is slid on from below, and then the piece of hardwood below it is turned 90 degrees to clamp it in place.
This cover does need to be removed when he table is tilted. |
 | This is the extra cover removed from the saw. |
 | This photo shows the piece for holding the dust cover around the blades. There's a small block of wood glued to the saw's cover right below this piece, so that when it's put against the saw, it cantilevered off that little block. This keeps it from scratching the paint off the saw over time. |
 | With the drive pulley directly attached to the bottom wheel, this does necessitate that the drive belt is in the "dust zone" on the bottom. The dust doesn't cause any problems for the V-belt, but I wanted to keep the dust away from the motor, especially because the motor I'm using is an open framed motor. So I made an enclosure around the drive belt. |
 | The enclosure for the most part keeps the dust contained around the belt and away from the motor. |
 | Another cover fits in the frame around the lower wheel mount. It actually mounts in at an angle. I figured that gives the dust a little bit more room to swirl around inside the enclosure, and hopefully separate out and fall out the bottom.This part of the enclosure just screwed to the bottom of the frame. |
 | Here's all the parts of the enclosure, plus the table. This was after the first coat of clear varnish. I put one coat of clear varnish on all the dust cover pieces before painting to act as a seal coat. |
 | A coat of paint is essential to make the saw look nice! I took all the parts outside and sprayed them. I just used ordinary indoor paint for the cover. Surprisingly, this thick paint can be sprayed.After the paint, I put another clear coat of varnish over the paint to protect it from scratches and give the saw a bit of a shine. |
 | And here's the saw with the painted dust enclosure.Apologies for not including more photos of the actual construction of the dust enclosure, but there really was very little to that enclosure that was tricky to make.
The enclosure isn't critical to the function of the saw, so you may chose to make a different style of enclosure for your bandsaw.
More details of how the enclosure goes together can be seen in the cad drawings. However, it is advisable to measure your saw for the enclosure dimensions rather than only using the dimensions in the CAD drawings. |
Getting the alignment right
 | If you build your own bandsaw, even if you work very carefully, you can't just assume your bandsaw will be aligned properly. The wheels of the bandsaw should be coplanar.If you check the wheels with a ruler as shown, and the wheels don't line up, its probably because your wheels are tilted forward or back. The top wheel is easy enough to tilt to align with the bottom wheel with the tracking knob. Aligning the bottom wheel is less straightforward.
But because this design mounts the bottom shaft to a block of wood attached to the bottom of the frame, you can just loosen the screws and add shims to get it to the right angle. The block of wood is 10 cm deep, which is a quarter of the wheel diameter. So with the ruler touching both wheels, and you find the top of the bottom wheel 4 mm from the ruler, you will need to add about 1 mm of shim between the front of the bottom wheel mount block and the frame.
Because the edges of your rims may have a bit of wobble to them (remember, we turned them so the crown runs true, but the edge might have some wobble), you should repeat this check with several different wheel positions before adding any shims. |
 | Another, equally important aspect of aligning your bandsaw is making sure that the side to side tilt of the wheels is parallel. In terms of airplane terminology, the previous check would be "pitch" while this would be "yaw".Using two straight edges pressed against the wheels as shown, check that the straight edges meet at the same point. That is to say, both straight edges should end at about the same forward/back position. If you are using 4' (1.2 meter) long edges, and they come within half a centimeter of each other, you are close enough. I actually had the ends of my edges as far as 2 cm apart at some point and the saw still worked ok.
As with he previous measurement, repeat this check with different wheel positions because the actual edge of the wheel may not be as true as the crown. |
 | If you find that your upper guide needs a small amount of adjustment as you move it up and down, it's best to shim it up with some UHMW tape. That tape is about 0.2 mm (.008") thick. The top arm is 10 cm wide. If you move the guide by 20 cm vertically and it needs a millimeter of adjustment as a result, you should shim it by about half as much to get it to be accurate.Be sure you have a very straight bandsaw blade when you adjust your saw to it. I found that several of the "Viking" bandsaw blades I bought have a slightly crooked weld to them. This is especially noticeable with the wider blades, so I have been doing my checks with a narrow blade. |
Motor speed and pulley sizes
 | I specify a 47" or 1200 mm V belt in the plans, but the actual length you will need depends on how deep you cut your V-belt groove, and how large a pulley you put on your motor. If you are using a 2900 or 3500 RPM motor, you should use a 1.5" to 2" pulley (35-50 mm). If you are using an 1450 or 1750 PRM motor, you should use a pulley around 3" or bigger. I'm using a 1750 RPM half horse power motor with a 3" (75 mm) pulley and a 47" belt. I managed to cut through 18 cm (7") thick maple with that, although I had to go slow. Bandsaws are very efficient saws. You shouldn't have any need for a motor bigger than 1 hp on your saw.If you use a 1/2 HP motor, a good blade speed to aim for would be about 1500 FPM, or about 7.5 meters per second. That works out to just under 6 turns per second of the wheels. If you put a blotch of paint on one of the wheels near the hub, you should be able to just barely count that out. If you have a more powerful motor, you might aim for a higher blade speed. My bigger homemade bandsaw has a 1.5 HP motor with a blade speed of about 2800 FPM. |
Moving it
 | My bandsaw, with motor and everything weights about 100 pounds (45 kg). This makes this saw relatively easy to move around. Here I'm lifting it onto my temporary bandsaw stand (it's actually my planer stand - haven't built a dedicated stand for it yet). I took the covers and blades off to get a better grip on the frame. It would have been easier to lift if I had taken the top wheel assembly out and removed the table. The frame is very light, but the wheels are heavier than those on commercial bandsaws. |
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