Segmented Ring Press
by Bob Tugwell
Having been tempted to try the segmented turning offered by Woodturning
Online, and starting with the 'beginners project' I soon realised
that I needed some kind of press to hold the ring layers in place
while
the glue was setting. For my first few attempts I used
my weighty toolbox, precariously balanced, to apply
the pressure. Clearly there was room for some
improvement on this method!
I cast around for ideas from various publications
etc..., and although I found some good presses I did
not have access to metalworking facilities which some
of them employed.
I wanted to make one from wood if possible, and I came
up with the idea using a cheap (hydraulic) bottle jack
and Newton's 3rd Law of motion!
The wood that I used for the main frame was Oak, with
the dimensions;
2 uprights 23" x 6 1/4" x 1 1/8"
top cross piece 13" x 6 1/4" x 2"
bottom (a piece of kitchen counter top)
13" x 13" x 1 1/2"
Holding everything in place are 8 coach screws. These
are coarse threaded about 2/3 along their length and
have hexagonal heads. I put lashings of pva glue
between the butt joints as extra insurance.
The rings to be glued are sandwiched between the
bottom chipboard laminate and a second similar piece
that is cut slightly smaller so that it moves with
ease between the uprights. I cut the second piece
about 12" square. By having the 'Formica type'
surfaces facing each other any glue that gets onto
these faces can usually be peeled off later when all
is set.
The jack has only a limited distance of travel when
pumped up. To compensate for this I cut 3 thick (ash)
blocks to use on top of the pressure plate, and each
other, as the height required. ie. when the gluing-up
is nearly finished and/or the bowl is quite deep,
maybe only 1 of the blocks will be required.
The top of the jack is only about 1" diameter, so I
sank a hole about 1/2" deep into the centre of the
underside of the top thinner block. The shaft of the
jack fits the hole tightly enough to hold the thin
block from moving while being pumped up. The thin
block is also a piece of kitchen counter top with
dimensions slightly less than the underside of the top
cross piece.
In practice I have found the press to be fine and
adequate for its intended purpose, although I have not
done a great deal of segmented turning. When I put
this press together I did so by instinct rather than
by careful thought and planning, consequently I expect
that any second press that I may make will incorporate
improvements that either thought or practical
shortcomings will demand. This process has already
started, see below!
Afterthoughts:
I could have made the base larger than the 13" square
which would then accommodate larger diameter bowls.
For tall vases the uprights could be longer.
The whole
press is quite heavy as it's probably
'over-engineered'.....and so the process of refinement
goes on.
I hope this idea may be useful to someone out there.
Should you wish to contact me my email address is: bobtugwell@yahoo.co.uk
I live in Cornwall in the UK. If you look at a map of
the UK mainland I live down in the bottom left hand corner surrounded
by the sea.
