Woodoworking question... (GaryM??...anyone?)

Egon · Mar 13, 2004

Richard:

OHHH NOOOO; not again; story of my life.

Always get confused.

It will change the dimensions and angles. the formuli should stay the same.

Now everyone knows why I always got to sit on the tall stool in the corner back when I had to attend school.

The board for an octagon [ six sides ] should be 9.4 inches and the angles at 30 degrees.

But hey; go for a hexagon.

Egon

Richard · Mar 13, 2004

( Now everyone knows why I always got to sit on the tall stool in the corner back when I had to attend school )

/forums/images/graemlins/grin.gif

Well, I took your diagram, moved it over to another piece of paper, making the changes to the numbers and now I'm at the Cos 60= X/6 and presuming that to be the correct format, I then went to internet to find the Cos of X/6...

Well...let's just leave it at now everyone knows why I too, always got to sit on the tall stool in the corner...AFTER I was done taking the erasers down to the vaccume machine to be cleaned... /forums/images/graemlins/blush.gif

/forums/images/graemlins/cool.gif

Egon · Mar 13, 2004

It will be cos 60 degrees = x/8 where 8 is the radius. This gives you 1/2 the length of the required board.

[cos 60 = .58778 ]

Egon

Richard · Mar 13, 2004

Thank you. Yet another gracious moment by a TBN member.

Richard

OkeeDon · Mar 13, 2004

I'm not big on the math, but I stayed at a Holiday Inn last night -- and I have a CAD program.

I started with a 16" diameter circle for your column, and set up the hexagon which would touch the circle. If it were me, I'd want the hexagon to be slightly larger than the column, so I drew parallel lines 1 - 1/2" out. The resulting shapes can easily be cut from a 2 x, (1-1/2" width), which I'd prefer over 1 x because it gives me more stability and more glueing and fastening surface.

The result gives 2 x boards that need to be 9.732" wide.

Probably the easiest thing to do is start with 2 x 10, which is 9.5" wide, cut the 30 degree angles, and assemble. That gives you a base where the inner edge fits inside the column diameter and the outside edge is slightly larger than the column diameter.

OkeeDon · Mar 13, 2004

A couple of extra thoughts. You'll need 6 pieces, each of which will be 9" long to give you your 9" filler. What I'd do is cut a piece of 2 x 10 to about 5' long, then rip the 30 degree angles on either side of the entire length. Be sure to set the inner edge of the blade on the exact apex of the 2 x 10, so the saw kerf does not narrow the board. Then measure the length of a piece (9") from the blade and set up a stop (clamp a block of wood in place). Feed your 2 x 10 up to the stop and cut. This gives you the best chance of each piece being exactly the same length.

Liberally glue the edges and shoot it with a brad gun. If you have a compressor, air powered brad guns are as cheap as $60 at Harbor Freight or Sams. If not, I just picked up a Powershot electric staple gun which will also shoot 5/8" brads -- $49.95 at Home Depot.

When you set up your saw for the 30 degree miter cuts, make some test cuts on scrap, and adjust the angle until you get nice miters.

GaryM · Mar 14, 2004

Sorry not to get here earlier, but OkeeDon's got your answers right there. Only difference is that I would probably try and use pocket holes and screws to hold it together. I have a Kreig Pocket hole jig that I find very useful. A little glue and drive two or three screws for each joint. One thing they do in their demos is make miters with the angle cut only on one piece rather than spiltting the total angle between the two edges.

Hank · Mar 14, 2004

If available and of sufficient capacity, the best way to bevel edges is with a jointer.

Hank · Mar 14, 2004

making the changes to the numbers and now I'm at the Cos 60= X/6 and presuming that to be the correct format, I then went to internet to find the Cos of X/6...


To lay out a hexagon, full size, within a given sized circle, here's a little trick I learned:

1. Set your dividers/compass/trammel points to draw the circle of the size required.

2. With the dividers/compass/trammel points still set, put the point of the instrument down anywhere on the circumference of the circle, and strike a mark where the pencil intersects the circle. Then, put the point on the new mark, and strike another mark. Continue around and you will have six equally spaced marks on the circle, and just connect the points for the inscribed hexagon.

OkeeDon · Mar 14, 2004

Yep, a hexagon forms 6 equilateral triangles, with each outer chord length equal to the radius of a circle that touches the points of the hexagon. I had never given it any thought until I drew the top CAD picture in my post above, and let the CAD program tell me the dimensions -- I was surprised that the length of the chord was exactly the same as the radius (8" in the example drawing). That's one of those tricks that experienced carpenters probably know, but should be taught in shop class to everyone. Your method makes it really easy and fast to lay out a hexagon without any sophisticated tools or math. It just went into my mental bag of tricks...