"Jim Wilkins" wrote in message
...
The candlestick was made in India, I am not sure how.

Probably cast.

On close inspection I suspect you are right.

The lathe doesn't drive the work, it only supports it between centers.
You could turn the work directly with the motor and belt from an old
sewing machine, or a rubber caster wheel chucked in a hand drill. Be
creative, think of things as what they could do rather than what they
were meant for.

I do. Some "thoughts" would make your hair stand on end...:-)

I tried to determine the
centre of the end to drill a concentric hole but found it almost
impossible.
In the end when hooked up to the live centre (which is loose on the drill
press table) the live centre was running around in a small circle
whatever I
did.

Fix that. A large pointed setscrew held by nuts and washers might
work. If you make the head slide down as I suggested you can drill
another small hole in the base plate near the large one. You can align
them with a piece of wire in the chuck, bicycle spokes work well. Turn
it slowly by hand and try to make the circle the point describes small
by bending the wire. Move the head until that small circle is centered
on your center point. You can check it with a ruler.

I have re-read this about six times and I am not altogether sure that I
understood: I have no difficulty aligning the centre point of the live
centre with the centre of the spindle. However, when I chuck the gnomon and
put the opposite end on the live centre (using the supposedly centre hole I
drilled), the gnomon, being slightly out of alignment, moves the live centre
around.


Now I understand (I hope!) that on a lathe the live centre on the
taistock
is lined up with the centre of the chuck on the head stock and the hole
will
be drilled in the centre by default. Not having a lathe the best way I
found
to drill centres in a round stock is to make a paper tube around it and
use
a tight fitting transfer punch to mark the centre. This works fine if the
stock is cylindrical, not on a candle stick stem which is not.

Make a pair of upright Vee supports out of thin material. Rest the
candlestick on them at places you consider circular. Turn it while
holding a supported pencil against the end. The pencil will mark a
small circle around the rotational axis.

How well did you learn Euclidean geometry? It has methods for finding
the center of a circle or any other shape. One simple way is to guess
at the center, put one point of a compass there and see how far off it
is when you rotate it. Find where the compass is out furthest and
correct half the error by moving the center point, then readjust the
other point to the circle and recheck. For me this centers within
about 0.010".

The euclid works if the cross-section is truly circular. In the case of this
piece it is not. Furthermore, the smaller the diameter (in ,my case about
1/4") the more difficult the method, even if the cross-section is truly
circular. I have used this:

http://www.leevalley.com/wood/page.a...65&cat=1,42936
(the centre-finding head)

but the transfer punch/paper roll method beats it every time particularly
for small parts. There is this:

http://www.victornet.com/cgi-bin/vic...uares% 3A1242

but I have never used it and wonder if it improves accuracy over the other
one. The other issue with very small parts is to actually hit the right spot
with a centre punch: I have been using a lamp with a magnifying lens and
even that is not particularly great. I am thinking of getting this:

http://www.leevalley.com/wood/page.a...=1,42936,50298

Maybe with a centre drill you do not need to punch? Am I right in that?



I found a thread on this group from 2004 which provided several options
of
which the only one viable in my situation would have been to use a 3-jaw
chuck to center under the drill press spindle and then substitute the
centre
drill. And I am indeed looking for a cheap 3-jaw chuck.

Are there any other suggestions ("Buy a lathe!" does not count)?

The other thing that puzzles me (and please note that the nearest I have
been to a lathe is in the movies and picutres in books) is how do you
start
turning something that is irregular in shape? Or even how do you turn a
round piece out of a square stock? Does it not do horrible things to the
cutting tool when it contacts only at the corners? Or is there a trick to
get the shape roughly round first somehow? I want to change the shape of
the
brass cup but the initial attempt was somewhat discouraging.

Brass is a little tricky but it has been turned into exquisite shapes
like watch gears with hand-held tools for centuries. Heron of
Alexandria's ancient Greek gadget book used (brass?) sheet metal and
turned shafts as if they were common hardware items back then. His
book described a steam engine and also a vessel with a secret
compartment that appears to turn water into wine.

If you keep the tool's support close to the stock you avoid those
horrible things, otherwise the lathe may practice knife-throwing. I've
only done a little free-hand turning of aluminum and can't give you
much detailed help. Trying to work metal without machine tools is like
going everywhere on foot.

I was basically using files supported by a wooden block as close as possible
to the piece. I am not brave enough yet to try a proper cutting tool.

I gotta get more space on Flickr - it is so much easier to show pictures.
Anyway, thanks for the advice.

--
Michael Koblic,
Campbell River, BC