Elliptical leg

[mare]

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.

[WillR]

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

power of accurate observation is commonly called cynicism by those=20 who have not got it.=94 George Bernard Shaw

[Dave Hinz]

You can get close with a lathe. I think I saw Roy do it a few years back. Think of the profile as two circles with different centers. Lay the circles and centers out on the end of the stock, and turn it once with each of the two centers. Gets you close to an ellipse - if mathematical precision is vital, nevermind.

I seem to recall that Roy had some fun with the very unbalanced work in the lathe - speed is probably not your friend in this case.

[mare]

It is, sorry. In a true ellips, there are no circle sections. The angle changes gradually. I want a leg the has (more or less) the same profile as the table.

It doesn't sound very safe to me.

[Stephen M]

Here's what I would do:

Laminate solid stock to yeild a 4x2.5 block

Draw your elipse on the end of your block

Rip 4 facets do that you have something that looks like a squashed octagon (stop sign). A 12-sided figure (6 rips) would be even better. Each rip should be tangent to the drawing of the elipe on the end of the block.

Double the number facets with a hand plane flattening each "corner" ( I think I would reach for my #5, but any bench plane would do).

Now you sould have something approaching a eliptical cross section. One more pass on each of the "corners" with a hand plane and you should be able to start in with abasives.

-Steve

[Steven and Gail Peterson]

You also can get a good start with a router with a 1" round over. Draw the ellipse on each end for reference. Round over all 4 side corners. I would then use my planer to reduce the place(s) that have the largest difference from the reference ellipse. Keep going until the shape is getting close. Finish by sanding.

We once renovated a kitchen, and put in a pair of cabinets that were rounded instead of having square corners. I had to make the curved quarter-round molding. Started with oak planks, cut the curves close to shape. Make many trips up and down the stairs for test fits. Once the curve fit, turning into quarter round wasn't too difficult.

Good luck Steve

[Teamcasa]

Offset turning is not all that hard if you chuck it properly. For a true ellipse, the turning on the lathe will get you very close with 4 offset setups. Finish with a spokeshave and card scrapers.

Dave

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[nlbauers]

Make yourself an elliptical router jig that would find around your stock. The jig would just be two ellipses that were the size of the target ellipse plus the router depth of cut. The bit would pass between the two sides of the jig while the router base rode on the outer diameter of the jig.

Neil

[Ken Grunke]

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

[Roger]

Does it need to be solid? I'd think in terms of cutting a number of elliptical disks of plywood, wrapping them with bending plywood to make an elliptical tube, and then veneering the outside in a vaccuum bag to yield your leg.

OTOH, for an elliptical section this small I'd probably do it by hand rather than worrying about a machine setup. Lay up a big enough blank, knock the corners off on the table saw and then use a hand plane or spokeshave to refine the shape (great excuse to buy the really sweet spokeshave from L-N. Make a cutout of the profile in a piece of plywood to check the shape as you go.

I've seen lathes for elliptical facework--mechanical contraptions that slide the headstock back and forth to keep the cutting position constant, but never lathe to turn an elliptical spindle. See for examples.

Roger

mare wrote:

[TheNewGuy]

Is a thumbnail router bit profile a 1/4-ellipse? If so (or, even if not), this would get the OP even closer to the final desired cross-section shape before having to sand/scrape/plane/spokeshave/etc.

Just a thought, Chris

Steven and Gail Peters> You also can get a good start with a router with a 1" round over. Draw the

difference

[J]

Drawknife to rough it out. Spoke shave to refine. Plane at the end to make sure you don't have any bumps. Should take about a half an hour.

-j

[WillR]

[WillR]

It is safe -- find the ornamental turners that I mentioned. There were some links in the rec.crafts.woodturning forum that I mention -- about a month ago? Interesting stuff.

I actually bought a 4 jaw independent chuck with this in mind...

And have some fun.

[alexy]

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.

[Tom Watson]

This is a perfect opportunity for a snipe hunt.

Draw the ellipse of your dreams up and cut it out on the bandsaur or with whatever you have that will make the cut.

Having created a pattern - take that sucker out and look for a really perfect piece of wood that fits it.

By that I mean that the wood is interesting and that the natural lines fit your pattern.

Old timey boat guys do this when looking for white oak knees for their projects> I hope that your project isn't white oak, because the boat guys are pretty thorough.

[Ralph]

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

[Roger]

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

[C & S]

You poor guy.

You have gotten at least 7 *completely different answers to this problem:

1. Table saw rip then plane
2. eccentric turning
3. Pure neander (draw knife/spoke shave)
4. Router template
5. Router bit (actually quite diffrent than 4)
6. Skelletin with skin
7. "Find the right tree"

Sorry, but since all of these are reasonable ('cept maybe the tree one) I find that amusing.

Let us know what you choose.

-Steve

Sorry if I missed one.

[Guess who]

I think he means that an ellipse has two "centers", or focal points. However, it won't work, as you suggest, since the ellipse is nowhere "circular", and no matter where the center, the cut will be circular to that center. I think no matter his choice of methods, each has its problems. The closest solution might be the one suggested to cut on the TS or bandsaw to rough shape then plane/sand to taste. The difficulty would be stabilising the already cut part while cutting the rest, but a wood channel and well-placed clamps should do it.