SASmith posted a blog showing how to make a scroll saw bowl from a flat board. As a slightly challenged
72 yr young apprentice I can no longer perform some tasks on a scroll saw, so here is my alternative.
I have a 1950s 12” Delta lathe and have a Delta 46-961 Compound Slide Rest that I received as a basket
case with many parts missing and rebuilt. You start the procedure by cutting a circle the maximum size
allowable by your board and lathe and attach it to a lathe face plate using a sacrificial board with a piece
of newspaper, or as I did for this blog by screwing the board directly to the face plate.
Place the faceplate on the lathe, and since the compound slide rest is not big enough, I have to mount
a custom built extension plate to the lathe and then mount the compound slide rest.
Since the extension plate has to slide to the proper length, I could not mount guides to line it up with the
lathe bed, so it has to aligned manually with a square. The parting tool takes about 3/16” of an inch out
of the board, so you can not cut it at 45 degrees as you would on a scroll saw you set the upper slide rest
at 43 degrees for pine and 42 degrees for hardwood.
You make your first cut on the outside diameter of the board to true up the circle and get the angle for
the bowl, then you measure in the thickness of the board from you first cut and set the outside of your
parting tool on the mark using the bottom slide rest, which moves at right angles to the lathe bed, then
start the lathe and cranking the upper slide rest cut the ring from the board. As you get closer to the lathe center the adapter is removed and the rest is mounted directly
to the lathe bed as shown in the last picture.
You continue to cut rings until you are too close to the mounting plate to make any more rings and you are
ready to stack and glue the rings as shown in this photo.
If you glue strips of contrasting hardwood together and make a smooth board, you can part off the rings
and then rotate them to make bowls like this.
If I am havilng a bad arthritis day, I can insert a special tool holder with a special ground cutting tool in
the compound slide rest as using both cranks at once I can cut bowls.
I acquired the compound slide rest in 2010 and Armstrong tool quit making the tool holders for the lantern
and rocker tool posts in 2005. Grizzly tool sells tool holders that will fit if you take a piece of 9/16” square
tool stock and cut a right angle shim that sets above and beside the tool holder to clamp it firmly in place.
If anyone is interested, i can do a blog on the rebuild of the Compound slide rest. There are compound
slide rests available from Grizzly and other places that can be adapted to a wood lathe for anyone that
might be interested. As far as I know, no one is manufacturing a compound slide rest for wood lathes.
-- As ever, Gus-the 76 yr young apprentice carpenter