http://www.getwoodworking.com September 2019 The Woodworker & Good Woodworking 69
to make furniture veneers, wall cladding and –
the reason for my interest – woodturning blanks.
When it comes to turning, JAZ certainly has
plenty of design potential, not least because it’s
rich in character. Just as with figuring in wood,
the variations that occur naturally during the
laminating process give each piece of JAZ its
unique patterning.
As a result of the moulding process, the JAZ
turning blanks are already dish-shaped, but
they’re also square. So, before I could do any
turning, I had to use a compass to mark out
as large a circle as possible within the blank
and then cut the corners off on the bandsaw
- the ideal tool for this job.
I planned to produce a finished bowl of 365mm
diameter, and if you do the same, your lathe
will need sufficient capacity. I turned this bowl
on my short-bed Graduate, but a lathe with
a swivel head should cope with the job.
Preparing the blank
I held the blank in my home-made jaws, which
fit onto an Axminster four-jawed chuck. Had
the blank not been dished, I would’ve mounted
it on a faceplate. I then set the lathe to run at
a low speed – 425rpm was sufficient for the
whole process – and turned a spigot with which
to mount the JAZ in a combination chuck. With a
bowl of this size, the bigger the chuck the better,
so I used a parting tool to turn a 100mm diameter
dovetailed spigot about 6mm deep and this fitted
into the Axminster Mega jaws, which have great
holding power.
Tough stuff
I could now turn the rest of the bottom, so I
sharpened my gouge and started turning. Within
seconds, I discovered just how hard and abrasive
this material is: just a few passes with the gouge
and I needed to sharpen it again. I found that
I could sharpen my gouge, turn off the grinder
and walk the three metres back to the lathe,
then take a few cuts, blunt the tool, and be back
at the grinder while it was still slowing down!
The point I am making is that you shouldn’t
expect to turn this material quickly; it will
take a fair amount of time and patience.
When I reached the finished shape, I took
light cuts that would leave the underside with
a reasonable finish, which was ready for sanding.
I found that the best and quickest way to finish
JAZ was to power sand and give it a light polish.Turning the inside
I discovered it’s very important that the blank
is well anchored to the lathe, so I put the blank
onto the chuck and made sure it was tight. I
placed the toolrest near the outside rim and
turned the blank around by hand to check that
it cleared the toolrest.I decided to leave the edge of the bowl flat, which
I thought would suit the bowl better than having
a rounded edge. Then, with a freshly sharpened
12mm bowl gouge, I attempted to turn the inside.
This was no easier than turning the rest of the
bowl, and I lost count of the number of times
I went back to the grinder to freshen the edge
of the tool.
As I was turning the bowl, I regularly checked
the wall thickness with figure-of-eight callipers.
I stopped the lathe while I did this, and moved the
callipers around the bowl, noting where I needed
to remove material to get an even wall thickness.
When I was turning the bowl I heard a ticking
sound, so I stopped the lathe and noticed that a6 Use a 12mm gouge to turn the inside and
watch the pattern of the JAZ’s layers reveal itself5 ... use a freshly sharpened gouge to true up
the outside of the bowl4 Reverse the bowl into the jaws on a combination
chuck, and then...
EXPERIMENTING WITH TOOLS
Throughout the turning of this bowl I tried
gouges of different makes and sizes; I even
tried scraping the inside of the bowl. All the
tools I used were high-speed steel, and I found
that the gouges turned the bowl quicker and
their performance was much the same as
the scrapers7 In the event of delamination, cut off the loose
part and re-turn the surface to remove the flaw