6x48" belt sander build continuedContinued from part 1
Once the belt sander was in this state I was confident that it would work. I ordered a piece of 3 mm thick sheet metal from the Metal Supermarket to use as a platen. This adds 3 mm of thickness, which is how much the rollers are above the plywood. But I realized, I should ideally raise it slightly higher to make sure the belt pushes against the platen a little.
I also experimented with using a piece of laminate flooring as backing material. I sanded a lot in the same spot to see how it would hold up, but I couldn't see any signs of wear afterwards. The main issue with the laminate flooring was that it's much thicker, so it lifted the belt quite a bit, and that made the sander much louder.
If running the belt at high speed, heat build-up might also be an issue. I have mine running at about 440 meters/minute or 1500 fpm.
Building the baseNext step was to build some sort of base for it so that the motor could be underneath the belt. Here checking the layout of the pieces I cut.
Then screwing the sander part to the base. Ideally, the piece of plywood on the back of the sander would extend down a bit further, but at this point I diverged from my initial design, so this wasn't very pre-planned.
Making the motor pulleyI had one 2.5" (63 mm) pulley but needed a second one for the motor (not the step pulley I first tested with). I bought a pulley, but it cost $10, which seems too much for a small piece of aluminium. Two pulleys would cost more than what I'll charge for the plans, so if I can show you how to save one pulley, that's already making up for more than half the cost of the plans!
I drilled the hole 31/64" in diameter, a bit smaller than the motor's 1/2" shaft. I then drove a nail in where the motor's flat spot is to act as a key to keep the pulley from spinning loose.
I didn't have the motor clamped down firmly enough, and the motor's mount is also a bit "springy", so there were some vibration issues. I ended up shaping much of it with a parting tool, mostly to take smaller cuts to cut down on vibration.
The motor needs to be bolted down to the base. The logical choice would be to use carriage bolts, but I have a whole bunch of these T-slot jig bolts left over from a 149 part jig and fixture kit I bought from Lee Valley Tools a few years ago, so I'll use those.
These require an elongated hole on the back, which I'm making by drilling overlapping holes with a Forstner bit.
Adding dust collectionI wanted a good way of collecting the dust coming off this belt sander without getting in the way too much. I had an idea for an adjustable dust collection shroud for this.
I used some small finishing nails to temporarily hold the sheet metal platen in place.
The piece of wood that holds the other side of this shroud could have been attached with long screws through the whole part, or with screws from the back (but the motor would be in the way of the screwdriver). I figured the most elegant way to attach it was with pocket holes from the inside.
Yes, pocket holes. I couldn't use my pocket hole jig because the ledge I already glued on was in the way, so I clamped another piece of wood to the side of where I needed to drill to help guide the drill in at an angle.
I attached that with a screw at an angle from below...
The pieces of wood have a rabbet cut in the side to accommodate the thickness of the plastic flange.
I also needed a way to lock the vertical position of the shroud.
I used a 1/4" machine screw, screwed
into a slightly undersized hole from the back, then a wing nut
on the outside, which presses a piece of wood against the ledges
that hold the dust collection shroud. Tightening the wing nut
locks it in place.
I'm using a clamp to temporarily hold the 3" dryer hose to my 2.5" dust collector hose, which leads to my small dust collector
Belt guard A belt guard isn't strictly necessary for a machine like this, but I figured I might as well build one.
I started by measuring the distance between the pulleys.
At this point I could call it done. But because I also want to be able to lie the sander on its side to use as an edge belt sander, an adjustable table is also necessary for this. I will get into that in my next article.
Kyle Scott's belt / disk sander
Simon Heslop's oscillating spindle sander