In message
, Fred
Holder writes
Hello John,

You've had several replies to your post, but I don't believe anyone
answered your question. I think a lot depends on the type of chucks
you use. A faceplate ring should work fine with a clamp down onto the
outside of the ring tenon provided your chuck has a dovetail like the
Nova Chucks have on their jaws. Then if you size the tenon for the
chuck to grip and make the dovetail match the chuck with the jaws
almost closed (this way they are the most round) the outside grip on
the faceplate ring should work just fine. It will run most true if you
have it so the chuck jaws fit against a shoulder on the ring.


Hi Fred
thanks for the comprehensive reply Interesting you say almost closed.
With the chuck jaws I have , I think the optimum diameter is a little
further out that, but as the manufacturers are so kind to provide
dimensioned drawings , its a big bonus I had assumed external
clamping should work , as we clamp to a turned dovetail in the wood,
though that does have an element of compression


Doing it this way you can make up faceplate rings to fit each of your
sets of chuck jaws, then you can choose a ring that fits your jaws
that are currently in the chuck. Incidentally, if you are making rings
to hold bowls, making the rings as large as possible will allow you to
have the screws in an area of the bowl that will be turned away when
you final turn the foot of the bowl. I suppose this would work also
for hollow forms.

Its interesting you say as large as possible. I have tended to uses the
smallest ring I have, probably because the maximum thickness wood I have
mounted in this manner has been 6 inches thick, so by the time the
screws penetrate into the wood I am starting to encroach on my bowl
material But I see your point the larger ring would definitely
provide a more stable platform. When I get a larger piece of wood I will
give it a try.

But definitely the plan is for several Faceplate rings of different and
the same sizes

I personally use a clamping grip on the tenon of a bowl with my chuck
jaws. I've found that this holds well and it eliminates the
possibility of splitting the bowl (rather suddenly) from the expanding
pressure when you use and expanding pressure in a recess to hold the
bowl.
Yes these expanding pressures can be a pain. Early on I had several
items break the internal dovetail. Sometimes the wall was just not thick
enough, others the wood would just split (very dry oak) The problem was
how much do you turn the chuck key. At what point does it provide
optimum grip, when is it too loose or when it over tight. Its not an
easy one to determine. I have tended to tighten till contact it
established fully then add a part turn to nip it up, but in some cases
its been just a little too much.
With the external clamping the worst I can see is distortion of the
tenon through over tightening, but there is also a limiting factor in
that you can only compress so far


Incidentally, I don't use faceplate rings, although I have several, I
simply start my bowls between centers (actually between the live
center in the tailstock and the face of the chuck jaws) and turn the
outside to finish shape including a tenon to fit the chuck that is
mounted on the lathe. I reverse the blank and mount it in the chuck
jaws with a compression grip and hollow out the inside. I final sand
the inside and outside and put on the finish. I then reverse bowl
again using one of several mounting devices (a vacuum chuck, a Rim
Chuck, a Longworth chuck, or a jam fit chuck with tailstock support).
All of the reverse chucking methods should use the tailstock support
as long as possible to ensure the bowl doesn't come loose.

I think a lot of this section is for next months lesson I have a lot
to learn, but the process is great fun
--
John