Replies

1. 
   KeithNewton | Jun 19, 2008 05:13pm | #1

   I don't think I have ever done this, and at first blush, I didn't think it would be too hard, but after looking at it, this is trickier than I thought.

   Lets just work through the math. If we start with a circle and divide it by 5, we will have a central angle of 72º for each piece of the pie. Then if we look out to the facets which will be the visible face of the legs, as the base of a triangle, we subtract 72 from 180º then divide by 2 to find the other angles of each triangle,which would be 108 by 2 = 54º.

   However the angle between each face is the larger number 108º since there are two of those triangles joined side by side.

   Just to get started though, If you are working from square stock, and use the base as one side, then you would tilt 18º off of the 90º other two sides to get your first two adjacent sides, then just keep flipping it if you have a left tilt. You will be needing to move your fence to hit the lines on your pattern.

1. 
   gracezla | Jun 19, 2008 10:32pm | #6

   Just to get started though, If you are working from square stock, and use the base as one side, then you would tilt 18º off of the 90º other two sides to get your first two adjacent sides, then just keep flipping it if you have a left tilt. You will be needing to move your fence to hit the lines on your pattern.

   OK. Thanks. This is helpful. Unfortunately, I have a right tilt saw. So. Fence moved to the left? Blade tilted to 90 degrees + 18 degrees = 108 degrees?

   Then flip end to end and make second cut? And then the same for cuts 3 & 4 ?

   I won't be able to use a 4 X 4" blank. My 10" saw won't make it through. But will it if I start with 3 X 3" stock?

1. 
   BenM | Jun 19, 2008 11:11pm | #8

   You did not say if you want the leg tapered but if you do that complicates the making of the jig.  If you are making only one table (4 legs?) I wouldn't bother with a jig.  By the time you made the jig, tested it and cut the legs you could have been done doing it by hand.

   Draw 2 pentagons onto cardboard, one for the top of the leg and one for the bottom.  If there is no taper you only need to draw one pentagon.  Trace the pentagon to the top and bottom of your blank.  Make sure the sides of the 2 pentagons align with each other so you don't end up with a twisted leg (which might be interesting if unexpected).  Use a drawknife to remove the bulk of the wood (from big end to little end - it's downhill grain all the way) and then a handplane.  If you haven't done this before you could draw guidelines along the blank but you will need to keep drawing them in as each stroke of the drawknife will tend to cut away the lines.  You will have 4 legs faster than you think!

1. 
   gracezla | Jun 19, 2008 11:57pm | #11

   Ben, thanks so much!  The sketches are incredibly helpful and generous of you. (There are to be five legs, and I hadn't thought tapered, but now I'm thinking slightly twisted, starting with the taper!)

1. 
   BenM | Jun 20, 2008 02:18pm | #12

   You're welcome, but the sketches are from a different poster.

2. 
   KeithNewton | Jun 19, 2008 11:55pm | #10

   You won't be needing to cut all of the way through the full depth of the 4 x 4. With the blade tilted, it will be coming out of the side of the cut each time.If you want to tapper the legs, you can do that on the jointer after getting the 5 sides. To do that, clamp a stop to the infeed table against the trailing end, so that when the work is brought down on the blade, the front end will land on the outfeed table, then just feed it on across a few passes. This way, you will be taking off a wedge from 0 to whatever depth the infeed is down. That may sound scary, but it really isn't dangerous if your stop is clamped good.

2. 
   daverichards | Jun 19, 2008 07:26pm | #2

   Do you have a bandsaw? I would be inclined to use that instead of the table saw. As was mentioned, you'd have to move the fence for at least some of the cuts to cut to the line. My thought is to work off the center of the blank. How about a jig that looks something like a lathe? the base would be wide enough to ride against the fence without letting the leg blank touch it. An indexing disk on one end would lock the rotation during the cut. And a jig like this could be used to cut legs with any number of faces by simple changing the indexing disk.

   I could make a drawing if you think it would help.

1. 
   gracezla | Jun 19, 2008 10:49pm | #7

   42242.3 in reply to 42242.1 

   Do you have a bandsaw? I would be inclined to use that instead of the table saw. As was mentioned, you'd have to move the fence for at least some of the cuts to cut to the line. My thought is to work off the center of the blank. How about a jig that looks something like a lathe? the base would be wide enough to ride against the fence without letting the leg blank touch it. An indexing disk on one end would lock the rotation during the cut. And a jig like this could be used to cut legs with any number of faces by simple changing the indexing disk.

   I could make a drawing if you think it would help.

    

   I do have a bandsaw.  I understand working off the center of the blank as with a lathe, and the principle of an indexing disk. But I can't envision the sled, or how it would put the blank at the proper angle.  And would I use double sided tape to secure the stock to the sled/jig?

   A drawing would be incredibly helpful, is what I think I'm saying, here.

1. 
   daverichards | Jun 19, 2008 11:15pm | #9

   View Image Here is a very quick sketch. It shows a leg blank about to be tapered. I omitted the indexing disk but it could be screwed to one end of the leg and a pin pushed through to prevent the stock from rotating.

   Looking at the left side, the left edge of the sled rides against the bandsaw fence. The width isn't critical as long as the stock and fence don't collide when the work is rotated. There is a pin in the center at each end of the stock--this could be a screw or a hanger bolt or whatever.

   The view on the right side is from the opposite end of the jig. Notice the pin is closer to the cutting side of the jig than at the back.

   You could do this same sort of thing with guides for a router to run on and use that instead of the bandsaw. I suppose you could do this on a table saw, too but I don't like the idea much. I think the bandsaw would be safer.

1. 
   USANigel | Jun 23, 2008 01:38am | #15

   Your pictures have me thinking lock in place and run through the planer.

1. 
   daverichards | Jun 23, 2008 03:33pm | #16

   Using the planer could be good and it would certainly be easy enough if you can find a good way to support the work along its length. View Image

3. 
   saschafer | Jun 19, 2008 09:15pm | #3

   Are you looking to cut the leg out of a solid blank, or build one up (like barrel staves)?

   -Steve

    

1. 
   gracezla | Jun 19, 2008 09:36pm | #5

    

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   42242.4 in reply to 42242.1 

   Are you looking to cut the leg out of a solid blank, or build one up (like barrel staves)?

    I had thought it should be made from solid stock, starting with a 4 X 4 blank, but maybe I should consider splining five sides together. WHY DOES NO ONE MAKE A ROUTER BIT THAT WILL CUT THE ANGLES FOR A FIVE SIDED BOX?

4. 
   QCInspector | Jun 19, 2008 09:32pm | #4

   http://www.josephfusco.org/Calculators/Advanced_Box_Cutter.html

   Try this for the math.

5. 
   douglas2cats | Jun 20, 2008 08:26pm | #13

   The first thing that came to mind was a jig Norm used to do tapered pencil post octagon legs a long time ago. This would probably be even easier with shorter table legs. But basically it was a box carriage of some sort with a pivot point on each end with the blank mounted on the pins, and sticking out of the box somewhat to the sawblade side. I think he just kept rotating the piece 22.5 degrees while at the same time the carriage was lined up on his shopmade taper jig.

   If you build it he will come.

6. 
   PaulMassachusetts | Jun 23, 2008 01:33am | #14

      You could glue up five individual boards that are cut to an angle of 360/5=72 degrees on the tablesaw. Splines might not be required because the glue up is long grain to long grain.  Possibly use biscuits but that might not be necessary. Straight grain helps stability. 

      The thickness and width of the individual boards are easily figured with old fashioned graph paper. Imagine looking at the leg assembly top down. Just pick a leg thickness, make a circle of that dimension,  and draw away (think five boards with angled sides top down) to make a 100% scale drawing. Measure actual final dimensions from the drawing.

      As you cut the wood at 72 degrees it tends to rise up-beware to use even pressure along the whole length. Use strong elastic bands to hold the assembly together until you put strong clamps on it. It is possible you might need to figure out a wood aid for clamping ahead of time.  

      I make elongated sections such as these for woodturning furniture projects. A 0.1 inch to 0.25 inch contrasting wood inserted between each prepared piece adds visual interest and zip. You can also make smaller pentagon boxes this way with scrap as a way to practice..