I built one of these sanders back in 1982 by following Andy Marlow’s plans in Fine Woodworking magazine. When I bought some large 3 phase machines in 1984 and moved my shop to a commercial space, I gave away the little stroke sander.
One of the first things I did in setting up a home shop last year was build a new stroke sander like my old one. This time I used larger angle iron and made the traveling table out of heavier stock.
After I mounted the motor, pulleys and a v-belt, I clamped a piece of angle iron to the sander frame. Then I used a big gouge to turn the glued-up pine squares into round drums. That was an unpleasant job!
I like its relatively small size, and the way it sands large flat panels up to 4 feet wide. I can sand narrow boards as well. It is open on the left side so that 8 foot long pieces can be sanded by turning them end for end under the machine. One of the advantages of a stroke sander is the way you can spot sand and feather out an area.
I made a 6″x7″ pine block to use as a sanding pad. It is covered with graphite cloth so that it slides easily on the back side of the belt. I also clamped a wood platen under the belt at the top of the machine so that I can hold small pieces right down on the belt.
Marlow recommended 60 grit belts made from heavy weight sandpaper, and I was dubious about whether these would actually work. It turns out that the belts work just fine. The belts last a long time and as they wear down they sand finer. A well worn 60 grit belt will sand something like a 100 grit belt. The paper belts are much cheaper than buying made-up cloth belts.
The belts are spliced at an angle by cutting through both ends at the same time with a box knife. I use a four foot straight edge along the belt to line up the splice to make sure the belt tracks straight on the drums. The cut ends are brought close together and two small brads are used on each piece to tack them down to a paper padded pine block.
A 1” strip of fine linen is glued across the joint, and followed by a 3” strip.
This is covered with 16 sheets of newsprint and another pine block. The whole sandwich is clamped together and left to dry thoroughly. The cured joint is peeled off the brads and the edges are trimmed down with scissors and a block plane.