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Band saw

Such extravagance

The only thing unusual about this wooden band saw is that there’s no video of it on YouTube.

Beech structural frame
Torsion arm mortise

12″ resaw capacity with a 16″ throat using Baltic Birch plywood with a Red Beech core. The back, front cover, and spacers will be Birch, but the structure will be a four layer 4″ x 5″ glue-lam of 4/4 Beech with a torsion arm ‘mortised’ in. I used Beech a while back for a camera studio stand and was really impressed with the strength, workability, and the cost as well. Certainly much cheaper than Birch plywood due to the conflict (Slava Ukraini).

The torsion arm should help to prevent flexing & twisting when the resaw blade is under load. I used the saw’s plywood panels as a guide to cutting and gluing up the Beech frame. Later, the frame will be glued to the back panel and 4 more rips of Baltic plywood will be added to the other side to provide spacing for the wheels and tension block.

Makeshift drill press
Truing shaft to wheel
Strong, if unrefined

I’m using some one-sided MDO Plywood for the wheels, which are 16″ in diameter. I cut out four 16.5″ MDO squares, and facet’d them as close to round as I could on the chop saw, then used a radius jig and a trim router to get them round. Afterwards I glued & screwed them together in pairs using the 0.25″” radius jig pivot pin for registration.

I don’t have a drill press so I made a makeshift drill guide one out of drawer slides and plywood scraps. Using a 0.25″ bit I was able to locate the drill guide for the shaft bores, then swapped out to a 1.25″ forstner bit. The 1″ carbon steel shafts (McMaster) will be set into epoxy, the margin will allow for additional truing up as well as room for the epoxy. I also ground coarse keyways into the shaft and to the wheel bore as well to strengthen the bond.

I used 5 minute epoxy to set the shafts in place, and used some some plywood gussets to ensure the shafts were kept perpendicular to the wheel during while curing. I clipped the inside bottom corner of the gussets to make sure they didn’t get thrown out of whack or glued in place by slumping epoxy. Some magnetic welding squares would have been nice for this step, but I ended up with only 0.015″ of runout per wheel, not too shabby for plywood.

Finally I made a plywood clamping hub to increase the wheel’s cross-section a little more. It’s just plywood with a clamping slit which is screwed to the wheel once it’s tightened down.

Tension & pivot block

For bearings I found some inexpensive pillow blocks (Amazon). They are surprisingly good. They’re sized for an interference fit (I was only able to fit them together by heating the inner race and freezing the shaft). I needed a slip fit for this project, but I was able to hone out the inner race enough on the spindle sander.

Each wheel has two pillow blocks. The upper wheel bearings are both mounted on the tension block, so they can be attached with through-bolts. The lower wheel was a little trickier to align the bearings since they were mounted on two separate sheets of plywood with a drive pulley in between (more on this later). The bearing’s pillow block cage has an adjustable alignment feature, which isn’t helpful in this situation since the wheels need to be in the same plane as the saw frame.

In situ
Hopefully I won’t need this much adjustment.

The tension assembly pivots on 0.75″ SS shaft in radial bearings mounted on either side of the screw block assembly, which is a hard maple block with a 5/8-16 threaded insert in the bottom and an outer plywood yoke to house the bearings. Once assembled, the whole fixture rides up and down in a housing in the upper wheel area that’s sectioned off with Baltic ply. The pivot is adjusted with a thumb bolt from the outside; the tension from a handwheel on top of the saw. Since it will be under lot of tension, the pivot bolt bears on a steel inlay in the pivot block.

Testing runout, only 20 thou across 16″ so I probably won’t need to face turn the wheels
Checking planar alignment

Once the top wheel was mounted and aligned, I used it to locate the bottom wheel. The bottom wheel is the drive wheel, and there is a plywood partition to house the drive pulley. The pillow blocks are mounting using threaded inserts, so they have to be exact. There is a little play in the casting mounting holes for the 3/8-16 bolts, but not a lot. Basically, I center and mount the bearing on the bottom, then find the truest location for the top bearing block before marking it out, carefully removing the wheel, and drilling for the inserts.

Yes, I once thought I could use a hot tub motor for this

The whole project was inspired by finding a 1.5 HP spa motor. It was enough to be able true up the wheels with a skew chisel, but just barely.

Once the wheels were turned true and to the same circumference, I weight-balanced them by drilling shallow lightening holes as needed with a 1.25″ forstner bit. Then it was time for a test run. I used some exercise resistance bands for tires and a 0.25″ blade for the trial run.

Of course the motor ran backwards, and of course the label said the motor was not reversible. After a minute of panic I found a YouTube video on how to switch the windings. Even so, it was quickly apparent that this motor didn’t have the start capacitance or torque for the 16″ wheels. Still the motor was enough to finish setting up the saw and table, and to do a few scroll cut tests using a .25″ blade.

Test run…
Lower guides. (I ended up making half of the lower front apron part of the door)
Upper guides, table support, and starting to fill in some gaps around the saw

For the top and bottom blade guides, I used Lignum Vitae blocks and a radial bearing behind the blade. Pretty simple. The entire guide assembly slides front to back to account for blade width and the bearing is independently adjustable front to back as well. The top guide has the same adjustments and slides up & down as well.

Table, upside down
Table, checking for flatness side to side and corner to corner

The table is two pieces, sub and top. The top is framed out with additional support plus a perimeter of plywood. The top fits over the sub tightly. This is to allow shimming the sub level and square before adding the top. (There is no tilt, I don’t have enough of a need to justify the design complication.) The gap for blade changes is reinforced by a piece of 8020 extrusion, the extrusion has t-slots that allow loosening and tightening from the screws above; the extrusion is loosened and slid out of the way to change blades.

I build a low cabinet with casters to put the table at a comfortable working height. The saw is mounted to a MDO plate, which is screwed to the cabinet top. The front of the cabinet is further reinforced with a 2″ x 3″ Beech beam.

Once I beheld the saw upright, I wish I would have put the tension adjustment below. I can reach it without a ladder, but barely. The saw is 6′ 7″ tall with the blade guide all the way down.

Switch and rear blade guide
Front blade guide

I made a cutout in the saw cover for the switch, then mounted it to a plywood block. The exposed resaw blade is intimidating so I made some rudimentary guards out of Lexan. The blade in the rear is totally behind Lexan, but the design of the front guide only allowed for an outer guard.

T-square style fence
Beech t-slot profile roughed out on table saw.
Profile screwed to table

The fence is a typical T-square affair, made from some aluminum scraps I had left over from old projects. Some of the 8020 extrusion is paired with some profiled rail cut from Beech on the table saw. A 0.25″ angle joining plate and some 2″ right angle extrusion allowed me to fit a piece of oversized aluminum box frame extrusion for a fence. The fence is removable using two thumbscrews. The fence clamps with a cam lever, end-to-end threaded rod, and some internal maple blocks. The block at the cam clamp end is attached with some roll pins and screws to keep it from shifting under clamping force.

New motor
Saw cabinet and under table view. Also shows the newer lower apron, with a dust collection port fit into the door apron
4/4 Cherry, 12″ resaw

I found a good motor on sale at Grizzly, a TEFC Induction 1.5 single phase motor. It can be wired 110/220, I’m using 110 for now. It had the same RPM and mounting pattern as my old motor, so I didn’t have to redo the mounting inserts or change the belt & pulley. The motor is a little longer, so I just had to shift the saw over on the mounting plate by 3/8″. Well worth it, the motor had no problem resawing through 12″ Cherry.

The wooden frame is really strong, only detecting 0.016″ of deflection when the resaw blade is under tension.

The build was expensive, given the current cost of Baltic Birch plywood and everything else. But as evidenced with the guitar case build I don’t make things to save money, I just enjoy the projects for themselves. Well worth it.