Once you've bought your lathe and some basic tools,
the next consideration is how you are going to grip the
work securely enough to allow it to be turned safely.
In fact, holding the work is more than half the battle in
woodturning, and with experience you'll soon develop a
range of different strategies to suit the item being made
and your particular way of working
Holding spindles is relatively easy, as
these are just held between centres
which fit into the Morse tapers of the
main spindle and tailstock, photo 1. The
drive centres for the headstock are available
in a variety of sizes and patterns, depending
on the diameter of work you are turning.
One with four prongs and a diameter of
about 1in will cover virtually all your needs,
photo 2. For smaller section material, a 5⁄8
or 1⁄2in diameter centre might be needed,
but don't bother buying one of these unless
you actually need it. There are some
two-pronged versions available, photo 3,
but these should be used with care as you
can split the work if you're too heavyhanded
with them.
The tailstock end
At the tailstock end, the work is supported
by another centre, which ideally should be
of the revolving type,
photo 4. Although
they're bulkier, they spin with the work so
you can apply enough pressure to get it
secure without worrying about overheating.
If you use the cheaper fixed or 'dead'
type of centre, there's a real chance of
burning the work,
photo 5, particularly if as
a nervous beginner you tend to overtighten
things. If your lathe comes with a dead
centre as standard, it's well worth buying a
revolving version. They don't cost a fortune,
but do buy a reasonable quality one; the
cheaper versions are often poorly made,
with inadequate bearings that can introduce
vibration problems,
photo 6.
That's all you need for working between
centres, but there are many situations
where you can't hold your work like this -
for example, when you need free access to
one end of the workpiece - but in this case
there is a much wider range of options
available for mounting the work securely.
Introducing faceplates
The conventional holding device is a
faceplate,
photo 7, and in fact a lot of flat
work is still called faceplate turning even if
it's actually held by some other means. I
was taught to turn in the days where a lathe
had just a set of centres and a faceplate. If
you couldn't hold the work by either of these
methods, you then had to make some form
of temporary wooden friction chuck as part
of each individual job.
Fortunately, things have moved on and
there's now a whole variety of very versatile
chucks that provide instant solutions for
virtually every holding situation. I'll cover
these in detail in the next issue.
Advanced chucking systems are now a
necessity rather than a luxury, and most
serious turners will have at least one.
However, there are still situations where a
simple faceplate, or its close derivative the
screwchuck, provides the easiest and most
efficient method of holding work. In fact, a
faceplate may be the only way of getting the
initial hold whilst you turn some sort of
spigot or recess for subsequent gripping
with a chuck.
Different sizes
Faceplates come in a variety of sizes, but
you don't need a lot. As usual, it depends
on what sort of work you do, but for general
use a 4in version is all that you'll need. It's
worth thinking about adding a 6in one if you
want to do a lot of big bowl work, and
perhaps a smaller one if your ambitions are
more modest,
photo 8.
Although a faceplate is apparently very
simple, it's important to buy a good-quality
one. I would prefer a machined steel
faceplate with a short boss, as this will run
true and is less likely to distort than the
aluminium versions. As well as distorting as
you screw them onto uneven workpieces,
the aluminium ones also tend to chew up
round the fixing holes after only a little use.
This doesn't happen with steel, photo 9.
Strength matters
Many of the cheaper lathes now seem to
come with a standard 6in cast-iron
faceplate, which as well as being thin and
not particularly accurate, also has a long
central boss which introduces another
potential source of distortion and vibration,
photo 10. It really is worth investing in a
better quality one.
Remember that if you have to screw the
faceplate on to a very uneven surface,
strength is very important, though you may
still have to pack it out in some situations if
you need to adjust the orientation of the
blank. Plenty of screw holes is an
advantage here; try to put a screw through
each packing wedge as well to stop them
flying out, photo 11.
Faceplate problems
When you start hanging big and heavy
pieces onto the spindle, it's vital that the
faceplate is screwed right up tight before
you start the lathe. It's so easy to leave it a
fraction of a turn off tight; then as soon as
you start up, the inertia of the blank causes
it to screw on with a juddering thump. This
makes it extremely difficult to remove later,
photo 12.
If jammed faceplates are something you
regularly struggle with, and you're sure they
are up tight before you start each time, then
try fitting a washer of some sort between the
plate and the headstock spindle. Any
material will do for this as long as it is soft,
photo 13. Cork, fibre, leather or cardboard
are all fine and a washer always eliminates
the problem.
Do also remember to clean out the
threads of the headstock spindle
occasionally, as this can stop the faceplate
screwing right up. Take great care not to
cross-thread it, particularly when loading
very heavy workpieces, as the spindle is
difficult and expensive to replace.
Screw on a chuck
An even more useful device for holding
workpieces is the screwchuck, and I would
rate this as one of the most useful lathe
accessories. Again available in various
shapes and sizes, this is essentially just a
small faceplate with a fixed central screw.
Common sizes are 11⁄2 and 21⁄2in in
diameter,
photo 14.
A standard screwchuck should take
normal woodscrews so you can replace
them as they wear. The only snag with this
is that they are usually No 14s, which can
be very difficult to find unless you know an
old-fashioned ironmongers. If you try and
use thinner gauge screws, they never seem
to lock in securely. Beware of screwchucks
with permanently fixed screws.
Varying the length
For maximum versatility, you need to be
able to vary the amount the screw projects
from the chuck. While you can do this to
some extent by changing the length of the
screw,
photo 15, better chucks will allow
you to adjust the seating position so you
can control the length more precisely,
photo 16.
If you're buying a screwchuck, try to find
one where the screw is held in by a
threaded boss and the head is retained by
a spline in the screw slot, photo 17. This
sounds very complicated, but all it means is
that the screw cannot then turn as you twist
it in or out of the work. Screwchucks that
rely on holding the screw just with an Allen
key into the side are rarely successful, and
become very frustrating to use - either the
screw keeps turning, or the work becomes
loose as you are working.
If you're on a limited budget and it's a
toss up between buying a faceplate or a
screwchuck, then buy just a 21⁄2in
screwchuck which has additional screw
holes. Then you can remove the centre
screw and use this as a small faceplate as
well, photo 18.
Screwchuck problems
Many newcomers to turning really struggle
to get a screwchuck to hold securely, and
give up on them as a result. This is a
shame, because it's one of the simplest
and most useful of all holding devices and
is foolproof as long as you follow a few
basic rules.
Firstly, it's important that you make the
pilot hole the correct size and drill it to the
right depth, photo 19. Forcing the
screwchuck in without a pilot hole will not
give a stronger grip but will actually work in
reverse, as the thread crumbles and strips
as it struggles to form.
Secondly, be aware that the action of
screwing in the chuck will throw up a burr
around the hole, photo 20. This will stop the
timber seating firmly, leaving a gap between
the screwchuck and the end of the timber,
photo 21. A tiny amount of play at the
chuck end becomes greatly magnified at
the other unsupported end, and any
attempt to turn with it like this results in the
timber being torn off the screw, which is
when most people give up!
A good seating
There are several ways of overcoming this
and getting a secure seating. If the chuck
has a central fixing boss, try dropping this in
lower than the rest of the chuck face so
there's somewhere for the burr to go when
you tighten up,
photo 22. For longer
pieces, firstly turn them between centres
and trim up the end square - or preferably
make it slightly concave,
photo 23, so that
the rim of the chuck fits up tight and there is
absolutely no chance of any wobble,
photo
24.
If you take this much care, it should be
possible to hold a piece of sound 3 x 3in
timber about 6in long with just a single
screw into the end grain, photo 25. If the
timber is soft or much longer, use the
additional screw holes as well, photo 26.
Sometimes, no matter how careful you
are, the screw will not hold in end grain. In
these situations, try drilling a hole through
the blank and putting in a dowel at right
angles to the grain. Once the screw gets
hold of this, photo 27, there's no way it will
come off! If you're attaching to cross-grain
work such as a bowl, then a single
screwchuck will hold surprisingly large
pieces providing it seats flat, photo 28.
Summing up
The one disadvantage of both screwchucks
and faceplates is that they are invasive,
leaving you with screw holes as a
permanent reminder of the holding method.
In the case of the screwchuck you can part
off clear of the screw, but this is rather
wasteful, particularly if you are working with
expensive timbers,
photo 29.
Nevertheless, both faceplates and
screwchucks are essential lathe
accessories and you'll need to use both of
them at some stage, no matter what type of
woodturning you are doing.
sparky
