mare wrote:
Hi,
=20
I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.
=20
I have several ideas how to make one, layering lots of pieces of
bandsawn wood (or plywood) and then shaving and sanding until I'm blue
in the face.
=20
Is there a simpler solution? The leg doesn't have to be tapered, just a=

piece of wood with a elleptical profile, about 6 x 10 centimetre (2 1/2=

x 4 inch) inches thick.
=20
Or should I order it from somewhere where they have a spindler moulder
and the required profile(s)? Or a CNC cutter. I only need one, and don'=
t
want it to cost me an arm as well.
=20

This wood be better in r.c.woodturning. I just crossposted.

Most look here -- but might miss it.

Some do some pretty fancy stuff.

There are some specialty sites on this type of ornamental turning. DAGS=20
on it. (ornamental turning that is)


--=20
Will R.
Jewel Boxes and Wood Art
http://woodwork.pmccl.com
The power of accurate observation is commonly called cynicism by those=20
who have not got it.=94 George Bernard Shaw

WillR wrote:
mare wrote:

Hi,

I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.

I have several ideas how to make one, layering lots of pieces of
bandsawn wood (or plywood) and then shaving and sanding until I'm blue
in the face.

Is there a simpler solution? The leg doesn't have to be tapered, just a
piece of wood with a elleptical profile, about 6 x 10 centimetre (2 1/2
x 4 inch) inches thick.

Or should I order it from somewhere where they have a spindler moulder
and the required profile(s)? Or a CNC cutter. I only need one, and don't
want it to cost me an arm as well.


This wood be better in r.c.woodturning. I just crossposted.

Most look here -- but might miss it.

Some do some pretty fancy stuff.

There are some specialty sites on this type of ornamental turning. DAGS
on it. (ornamental turning that is)



How about a router carriage, the length of the spindle, with an
adjustable edge guide. The blank is held between centers in a lathe-like
setup (or a lathe itself, if possible) with an elliptical template
attached to one end. Use an end-cutting bit in the router, whose depth
and positon is set to the template. It would be necessary to lock the
blank in position, while making the cut the full length--then move the
spindle a few degrees each time, adjusting the depth and lateral
position of the router so it cuts tangent with the curve. Round the
facets off with a sander.

Ken Grunke

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Ken Grunke wrote:
WillR wrote:

mare wrote:

Hi,

I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.

I have several ideas how to make one, layering lots of pieces of
bandsawn wood (or plywood) and then shaving and sanding until I'm blue
in the face.

Is there a simpler solution? The leg doesn't have to be tapered, just a
piece of wood with a elleptical profile, about 6 x 10 centimetre (2 1/2
x 4 inch) inches thick.

Or should I order it from somewhere where they have a spindler moulder
and the required profile(s)? Or a CNC cutter. I only need one, and don't
want it to cost me an arm as well.


This wood be better in r.c.woodturning. I just crossposted.

Most look here -- but might miss it.

Some do some pretty fancy stuff.

There are some specialty sites on this type of ornamental turning.
DAGS on it. (ornamental turning that is)



How about a router carriage, the length of the spindle, with an
adjustable edge guide. The blank is held between centers in a lathe-like
setup (or a lathe itself, if possible) with an elliptical template
attached to one end. Use an end-cutting bit in the router, whose depth
and positon is set to the template. It would be necessary to lock the
blank in position, while making the cut the full length--then move the
spindle a few degrees each time, adjusting the depth and lateral
position of the router so it cuts tangent with the curve. Round the
facets off with a sander.

Ken Grunke

----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet
News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+
Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

Ken:

Forgot about that idea. It's in the Router Magic book -- or sumpin like
it. If the guy is interested in the idea I can dig out at least one plan.

--
Will
Occasional Techno-geek

Ken Grunke wrote:

WillR wrote:
mare wrote:

Hi,

I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.

I have several ideas how to make one, layering lots of pieces of
bandsawn wood (or plywood) and then shaving and sanding until I'm blue
in the face.

Is there a simpler solution? The leg doesn't have to be tapered, just a
piece of wood with a elleptical profile, about 6 x 10 centimetre (2 1/2
x 4 inch) inches thick.

Or should I order it from somewhere where they have a spindler moulder
and the required profile(s)? Or a CNC cutter. I only need one, and don't
want it to cost me an arm as well.


This wood be better in r.c.woodturning. I just crossposted.

Most look here -- but might miss it.

Some do some pretty fancy stuff.

There are some specialty sites on this type of ornamental turning. DAGS
on it. (ornamental turning that is)



How about a router carriage, the length of the spindle, with an
adjustable edge guide. The blank is held between centers in a lathe-like
setup (or a lathe itself, if possible) with an elliptical template
attached to one end. Use an end-cutting bit in the router, whose depth
and positon is set to the template. It would be necessary to lock the
blank in position, while making the cut the full length--then move the
spindle a few degrees each time, adjusting the depth and lateral
position of the router so it cuts tangent with the curve. Round the
facets off with a sander.

I was thinking of exactly the same process, with different tools: a
bandsaw to cut the rough facets, and a plane to bring to final shape (
and a flexible card scraper if the tiny flats still left by the plane
are undesirable).

Same idea--just whatever tools you have available and are most
comfortable or prefer to work with.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

Turn The leg on two offset centers at 180 degrees with the center point
equal distant from the center.

Ralph wrote:
Turn The leg on two offset centers at 180 degrees with the center point
equal distant from the center.



I guess I'm missing something. How does this form an ellipse? Aren't
the ends going to be circular rather than elliptical in section? Unless
the lathe moves the center while rotating as is possible with some
ornamental lathes the section can't be elliptical.

Roger

It may not be truly elliptical but it will look more like an ellipse
than a circle.

"Roger" wrote in message
...
Ralph wrote:
Turn The leg on two offset centers at 180 degrees with the center point
equal distant from the center.



I guess I'm missing something. How does this form an ellipse? Aren't
the ends going to be circular rather than elliptical in section? Unless
the lathe moves the center while rotating as is possible with some
ornamental lathes the section can't be elliptical.

Roger

No, this won't form an ellipse, but with proper layout it can form a
reasonable approximation. I did a quick sketch in AutoCad to see what could
be done. Start with a cylinder 4" in diameter and offset it ~1.3" at both
ends and turn .75" of material from the highest spot. Have extra length and
do NOT turn all the way to the ends , because the offsets are outside the
finished ellipse. Now offset if again 1.3" from the original center but in
the opposite direction as the first offset. Again turn .75" material from
the highest spot. This will leave 4 lines the length of the "ellipse" where
the original cylinder and the two offset turnings intersect. These lines
are about 0.035" proud of the true ellipse and should be easier to hand sand
to blend the curves. This is still not a true ellipse, as you go from the
major diameter to the minor diameter the piece is a bit shy, with the
maximum deviation being about 0.05". This might be good enough for his
purposes.
Hope this helps
Martin

In article ,
Roger wrote:
Ralph wrote:
Turn The leg on two offset centers at 180 degrees with the center point
equal distant from the center.



I guess I'm missing something. How does this form an ellipse? Aren't
the ends going to be circular rather than elliptical in section? Unless
the lathe moves the center while rotating as is possible with some
ornamental lathes the section can't be elliptical.

Roger

Consider a circular cylinder.

Consider what you get if you slice that cylinder at an angle.

Now, construct a cylinder perpendicular to that angled cross-section slice.

You have, obviously, and elliptical cylinder.

It should be "obvious to the casual observer" that you can take an angled
slice of _that_ cylinder in a manner that will yield a circular cross-
section. That cross-section is perpendicular to the minor axis, and at
an angle to the major axis such that the 'diagonal' is the same length
as the major axis. Mathematical "proof" gets a little messy, but is
fairly straightforward -- take the equation of an ellipse, parameterized
as a function of the major and minor axis lengths, set the two lengths
equal, and "reduce".

"A quantitative answer is left as an exercise for the student." *GRIN*

On Thu, 21 Apr 2005 17:41:01 -0000, Robert Bonomi wrote:

Consider a circular cylinder.
Consider what you get if you slice that cylinder at an angle.
Now, construct a cylinder perpendicular to that angled cross-section slice.
You have, obviously, and elliptical cylinder.

Right, ... so far, so good.

It should be "obvious to the casual observer" that you can take an angled
slice of _that_ cylinder in a manner that will yield a circular cross-
section. That cross-section is perpendicular to the minor axis, and at
an angle to the major axis such that the 'diagonal' is the same length
as the major axis.

You just broke my brain.

Mathematical "proof" gets a little messy, but is
fairly straightforward -- take the equation of an ellipse, parameterized
as a function of the major and minor axis lengths, set the two lengths
equal, and "reduce".

Or, he could just make a template, turn it close-enough, and fine tune
it to fit.

"A quantitative answer is left as an exercise for the student." *GRIN*

Hm. Sometimes, "close enough" is, well, close enough.

"Martin Rost" rostmartin @ hot mail . com wrote:


I did a quick sketch in AutoCad to see what could
be done.

Interesting idea. Seeing your note spurred me to do the same thing
with another approach. Starting with a 2-1/2" x 4" rectangular blank,
and with the table saw blade or band saw table set at 30 degrees, cut
an elongated hexagon with sides tangent to the ellipse. The resulting
points to plane off vary from slightly under 1/8" to slightly under
1/32" proud of the ellipse, with the worst ones being on the flat
side. Cut four 15-degree bevels with the stock vertical before moving
to the 30-degree bevel, and there is really very little planing to do.

As someone else said, lots of good approaches to this one.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

(Robert Bonomi) wrote:

In article ,
Roger wrote:
Ralph wrote:
Turn The leg on two offset centers at 180 degrees with the center point
equal distant from the center.



I guess I'm missing something. How does this form an ellipse? Aren't
the ends going to be circular rather than elliptical in section? Unless
the lathe moves the center while rotating as is possible with some
ornamental lathes the section can't be elliptical.

Roger

Consider a circular cylinder.

Consider what you get if you slice that cylinder at an angle.

Now, construct a cylinder perpendicular to that angled cross-section slice.

You have, obviously, and elliptical cylinder.

It should be "obvious to the casual observer" that you can take an angled
slice of _that_ cylinder in a manner that will yield a circular cross-
section. That cross-section is perpendicular to the minor axis, and at
an angle to the major axis such that the 'diagonal' is the same length
as the major axis. Mathematical "proof" gets a little messy, but is
fairly straightforward -- take the equation of an ellipse, parameterized
as a function of the major and minor axis lengths, set the two lengths
equal, and "reduce".

"A quantitative answer is left as an exercise for the student." *GRIN*


True, but irrelevant to what I understood to be suggested. I think the
offset idea was to turn two circular arcs of relatively large
diameter, which combine to form an elongated curved pointy-ended shape
that then can be further worked with planes, scrapers, sanders, etc.,
to approximate an ellipse. As I understood it, both ends of the leg
were going to be offset in the same direction, thus the concern for
caution with inherent imbalance.

I think what you are talking about can be used to cut a circle in a
single slanted plane, which will be useful as a gauge cut for the
ellipse. But the ends of the leg will have to be offset pretty darned
far from the lathe center if the leg is of any length.
--
Alex -- Replace "nospam" with "mail" to reply by email. Checked infrequently.

On 21 Apr 2005 17:53:14 GMT, Dave Hinz wrote:

It should be "obvious to the casual observer" that you can take an angled
slice of _that_ cylinder in a manner that will yield a circular cross-
section. That cross-section is perpendicular to the minor axis, and at
an angle to the major axis such that the 'diagonal' is the same length
as the major axis.

You just broke my brain.

He just makes it sound tough. Shine a flashlight straight down and it
lights up a circle. On an angle it's an ellipse; has to do with trig
if anyone insists. It still doesn't solve the probelm. Beside most
layout is based on some hefty math, but the layout is to make it all
easier. That's what got perspective geometry into the game, making
tough to impossible jobs relatively simple. An ellipse can be drawn
using two concentric circles and lines form the center ...etc..

But this doesn't in any way make "turning" a rectangle into an ellipse
over a length of material any easier. There might be some giant
industrial shaper around that would do it. The ellipse is symmetric
....the same in four sections... so only one section needs to be dealt
with at a time, then times four. Baring an industrial machine, I'd go
for approximate cuts on an oversize piece using the table saw, then
hand plane then sand as was suggested earlier.

I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.

There are no simple solutions to turning an ellipse, or an oval for that
matter. You might get some ideas from these websites. Dan


My oval turning lathe nearing completion
http://www.claycritters.com/lathe/

The Elliptical Turning Association
http://www.elliptical-turning-association.co.uk/

THE SOCIETY OF ORNAMENTAL TURNERS (U.K.)
http://www.the-sot.com/

ORNAMENTAL TURNERS INTERNATIONAL (AMERICA)
http://www.turners.org/

THE OLD SCHWAMB MILL
http://www.oldschwambmill.org/

More Woodturning has had oval turning articles
http://www.fholder.com/Woodturning/woodturn.htm

Piece of wood+drawknife+spokeshave=eliptical leg.

"Dan Bollinger" wrote in message
news:YZAae.15046$NU4.12798@attbi_s22...
I need (well, would like) one elliptical leg for the end of an
elliptical table. The other end will be attached to a wall, so it only
has one leg.

There are no simple solutions to turning an ellipse, or an oval for that
matter. You might get some ideas from these websites. Dan


My oval turning lathe nearing completion
http://www.claycritters.com/lathe/

The Elliptical Turning Association
http://www.elliptical-turning-association.co.uk/

THE SOCIETY OF ORNAMENTAL TURNERS (U.K.)
http://www.the-sot.com/

ORNAMENTAL TURNERS INTERNATIONAL (AMERICA)
http://www.turners.org/

THE OLD SCHWAMB MILL
http://www.oldschwambmill.org/

More Woodturning has had oval turning articles
http://www.fholder.com/Woodturning/woodturn.htm

Impressive video. Would such a Volmer type lathe be also of use with a
longer piece of wood? Say 75 cm (30")? Or would you need a similar
contraption on the other end, linked/synced to the one closer to the
lathe?

thanks! Yes, you'd need something on the other end for spindle turning
unless you were OK with it gradually turning from an oval to a circle by
using a standard dead center.

Piece of wood+drawknife+spokeshave=eliptical leg.

At some point carving it by hand is the cheaper way to go. Of course its a
little difficult to make a bead or cove using only a drawknife, but your
point is well taken nonetheless.

Besides carving...

a person could also fabricate this from gluing up multiple sections of split
turnings...

or use a copy lathe like they do for oval axe and hammer handles...

or program a CNC lathe...

or turn a hollow tube and steam bend into an oval by squishing it in the
middle...

all sorts of ways! Dan

If I were to do this, and I didn't want to hand carve it, I would likely do
it on a CNC vertical mill. "Didn't suggest that as few people have that at
their disposal.

"Dan Bollinger" wrote in message
news:OgPae.16136$r53.10548@attbi_s21...
Piece of wood+drawknife+spokeshave=eliptical leg.

At some point carving it by hand is the cheaper way to go. Of course its
a
little difficult to make a bead or cove using only a drawknife, but your
point is well taken nonetheless.

Besides carving...

a person could also fabricate this from gluing up multiple sections of
split
turnings...

or use a copy lathe like they do for oval axe and hammer handles...

or program a CNC lathe...

or turn a hollow tube and steam bend into an oval by squishing it in the
middle...

all sorts of ways! Dan

It's not elliptical, really, and in any case needs some handwork at the
end to blend it, but you certainly could get "close" with 3-center
turning, the same way many "oval" things are turned on regular lathes.

You tun on center to the profile you want the "fat part" (long axis of
the oval/ellipse) to be.

You go offcenter and turn one side down to (or as close as you want it
to) the centerline. You turn the other side to match. You're a lot
closer to where you want to be when you pull out the inevitable
spokeshave, and the evitable or not rasps, files, and sandpaper.

Try some test pieces - there's a bit of a trick seeing/feeling when
you've gotten the sides where you want them.

A lot more accessible to most mere mortals than anything that will cut a
true ellipse leg shape.

Or the really easy (but slow) way - turn the leg round out of green
wood, and wait for it to dry. Differential shrinkage will get you quite
a ways along with this approach.

If I were to do this, and I didn't want to hand carve it, I would likely
do
it on a CNC vertical mill. "Didn't suggest that as few people have that at
their disposal.

Speaking of ovals. My oval turning lathe is nearing completion. I've been
working on it for over three years. And no, it won't do oval spindles! Dan

http://www.claycritters.com/lathe/

I believe the problem can be solved throught the use of a spindle drum.
construct a drum to proper specifications of the leg, length. place recesses
in each end plate to hold the stock then add a second end plate. Mount the
number of legs you wish to turn in the drum attaching with a screw through
each end. The drum should contain spacers between each of the mounting
points. you turn you turn down to the spacer prior to mounting the legs. You
can use stock of any size as long as the recess is properly constructed. I
am being simplistic in my description but I am sure there are people out
there who could help..

To turn an ellipse turn the stock to the desired thickness and shape. then
remount each leg by tuning it over once. 180 degrees. the circumference of
the drum will dictate the curve. Old europe spindle turners used this
technique often and keep a variety of drums and sample patterns on hand.

I believe the problem can be solved throught the use of a spindle drum.
construct a drum to proper specifications of the leg, length. place
recesses
in each end plate to hold the stock then add a second end plate. Mount
the
number of legs you wish to turn in the drum attaching with a screw through
each end. The drum should contain spacers between each of the mounting
points. you turn you turn down to the spacer prior to mounting the legs.
You
can use stock of any size as long as the recess is properly constructed.
I
am being simplistic in my description but I am sure there are people out
there who could help..

To turn an ellipse turn the stock to the desired thickness and shape. then
remount each leg by tuning it over once. 180 degrees. the circumference of
the drum will dictate the curve. Old europe spindle turners used this
technique often and keep a variety of drums and sample patterns on hand.


That's a elegant solution, especially if you need more than one spindle.
You didn't say, but it should be noted, that the two end plates are firmly
attached to each other by a central shaft. It will make a bobbin shape. This
insures that the end plates travel in unison. The bobbin shaped drum is
turned between the centers. Actually, I'd use a face plate attached to the
drive side plate. Dan