If you have ever dabbled in woodturning,
and specifically in bowl turning, you would have come across the
problem of trying to refinish the bottom of your turned bowls
after you have hollowed out the bowl itself. Because of the
general process or procedure of bowl turning, where the back
side and bowl foot/bottom is turned first, and then this foot is
chucked up to hollow out the inside of the bowl, the chucking of
the bowl's foot often leaves chuck marks or indentations that
need to be smoothed out or re-turned to remove them. The problem
is that it is very difficult to re-chuck a bowl using its top
outer rim with conventional woodturning chucks.
Wood turning machine and chuck manufacturer,
Teknatool, designed the Cole Jaws to solve this common
The Nova Cole Jaws
The Cole Jaws are an accessory set of jaws designed to fit
the Teknatool Nova, Supernova, Supernova2, Titan and G3 woodturning chucks. They are named "Cole
Jaws" after one of Teknatool's woodturning demonstrators, Trevor
Cole, who helped design and produce the jaws to solve that
common problem of re-chucking bowls to finish the bottoms, or to
remove the foot completely to producing a smooth bottomed bowl. The
"Nova" part of the name comes from Teknatool's best selling line
of Nova and SuperNova woodturning chucks.
The Cole Jaws comprise four separate, but
identical metal plates. These plates attach directly to the
chuck's jaw slides using threaded screws supplied. Each plate
engages in the small radius groove found on these Teknatool
jaw slides, and the screw mounts line up with the existing jaw
slide tapped screw holes (which also allow fitting of a wide
variety of other Teknatool jaws and accessories). All plates are
machined to the same specs and design, so attaching the plates
in a specific order or configuration is not required, hence
simplifying the installation process.
Each plate has a further 14 additional tapped
screw holes radiating out from the "center" of each plate. These
holes are designed to accommodate the round rubber holders, of
which two are attached to each plate, making a total of eight
holders on the fully assembled Cole Jaw. The rubber holders are
what hold the bowl in place via a friction grip.
You can move the holders to any of the screw
locations on each plate but given that, in most cases, the rim
of your bowl will form a perfect round shape, each stopper will be located in a
screw hole the same distance from the center of the jaws. You
should select a holder location that allows the bowl to fit
within the diameter created by the eight rubber holders, so when
you tighten the jaw slides on the chuck itself, a firm grip is
attained on the outer edge of the bowl. Because of the rubber
design, bowls hold very well once secured and the rubber surface
creates virtually no problems with marking or marring your
Once a bowl is mounted in the Cole Jaws, you have
free access to clean up the bottom of the bowl and its foot with
your turning tools, to remove the foot altogether with further
tooling, or to finish it appropriately with a woodturner's finishing product. There is no way to hold a
decent sized bowl
like this with a regular woodturning chuck without additional
accessories like the Cole Jaws (unless you have a very small
You can achieve a similar grip on a bowl using a
specialized vacuum chuck, but these are generally much more expensive to
purchase initially, and require much more setup time, plus a
compressor and fittings to use it. The Cole Jaw is a much
simpler and more cost-effective method for re-chucking bowls.
Now, there are certain considerations to using
the Cole Jaws. First, the Cole Jaws we tested were model JSCOLE.
These jaws, out of the box, allow chucking of a bowl up to 10
inches in diameter. They can be used on any lathe that has a 10
inch or greater swing over the bed. If you have a mini-lathe
with less than a 10 inch swing, Teknatool also make Mini-Cole
jaws to suit these smaller lathes.
If you need a diameter capacity greater than 10"
for a larger bowl, you can actually make your own MDF segments
to attach to the Cole Jaws. Full instructions for doing so are
provided in the printed manual included with the product. The
manual itself is well-written, but apart from the safety
information included, I didn't really need to reference it to
assemble the Cole Jaws. It all goes together easily and
The other issue with using the Cole Jaws is that
they have a maximum recommended speed of 600 RPM when in use.
This didn't present a problem in use for me personally, but a
lower lathe speed does mean you have to take any re-finishing
cuts a little lighter, and take care in doing so. Naturally, a faster lathe
speed, especially when working around the center point of a
piece, makes cutting easier and a little smoother, but any
re-finishing cuts will generally be very light or shallow anyway
so 600 RPM seemed fine for me. Besides, you don't want an
attachment that large spinning too fast! The individual plates
seem very well balanced and there was no noticeable vibration
caused when using the Cole Jaws at the recommended speed.
For re-finishing the base of a bowl, you do not
really need to perfectly re-center the bowl in the Cole Jaws,
although you can quite easily get it as close to perfect as it
needs to be without too much problem. The very small margin of
error (or degree the bowl is off-center when re-chucked) will
hardly be noticeable on the finished piece.
Overall Use and Opinion
Using the Cole Jaws is child's play. It is very simple to
use. Just position your rubber holders as required for the
diameter of the bowl, place your bowl in the center of the ring
of holders with its top rim flat against all four Cole Jaw
plates, then use your chuck wrench to tighten the jaws of your
chuck, and hence the rubber holders, around the edge of the bowl. Your bowl is now chucked up
with the bottom exposed ready for final tuning, sanding and
finishing. The most time is consumed actually attaching and
removing the Cole Jaw plates from your existing Teknatool
woodturning chuck. However, there is a solution to this as well
which is well thought out. You can purchase another set of jaws
from the Teknatool range or use the jaws that come with your
chuck (if appropriate) and mount these onto the Cole Jaw plates.
This then allows you to turn a bowl using regular jaws (for bowl
shaping) without having to add and remove the Cole Jaws each
time you wish to re-chuck a bowl for foot finishing. A nifty
There is no point spending a good amount of time
actually crafting your woodturned bowl only to have some
annoying chuck marks on the foot of the bowl ruin the overall
look. For the retail price of around AUD$99 / USD$79 the Nova
Cole Jaws are an essential accessory for all woodturners who
craft turned bowls on a regular basis.
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Nova Cole Jaws
In the USA
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One of the Cole Jaw plates
Cole Jaws mounted on a
SuperNova 2 chuck.
The reverse side of the Cole Jaw plates.
Rubber holders secure the bowl.
Note how this chucked bowl is only half finished from chucking via the
foot and a normal woodturning chuck. Here you can see how I have access to
the full base/bottom of the bowl to refine the foot and sand and finish
Smoothing out the foot of the
bowl with a shear cut.
To view video of the
Cole Jaws, including
the False Wooden Jaws
Click on the Image