Wheel Making

36 degrees

Re: Wheel Making

Clifton C

I think it's 36...

Re: Wheel Making

Stuart Johnson

Calculating this the same way as a segmented disc the angle is 36 degrees, with a segment length 14-1/2 inches. The width of your board will determine the inside diameter.

Re: Wheel Making

Larry

Thanks, To every one!

Re: Wheel Making

Don Stephan

Someone please double check my memory and calculations . . .

The length of the circumference of a circle is 2 times 3.14159 times the radius, or 3.14159 times the diameter, here 20", so the circumference would be 62.83 inches. If the circumference is divided into 5 equal segments each would be 12.57" along the curve.

There are 360 degrees in a circle, so I would think five equal pie shaped pieces would each have an interior angle of 360 divided by 5, which my calculator says is 72 degrees.

A triangle with one vertex at the center of the circle and the other two at opposite ends of one of the segments on the circumference would be an isosolese (how is this dad burned word spelled anyway) triangle, meaning the outer two angles are the same. There are 180 degrees in a triangle, and if the center angle is 72 degrees then each of the outer angles would be one half of 180 minus 72, or 54 degrees. The angle setting on a miter saw may be the complement of this angle, 90-54, or 36 degrees.

Finding the straight line length between the two ends of each segment would require a trig calculator or table, and I have neither here.

Isosceles

Re: Wheel Making

Larry

Should said Wagon Wheel with Spokes.

My bad...

Barry Irby

I did not see the request for the length. OTOH, I could not have answered that part, at least not without drawing it out.

I have a friend who could work it out on a computer with Autocad. When I need help I call him.

I this case what I would do is draw it out. Big piece of paper or plywood and a compass. Then sketch it from there.

The way I do the angle is 2 the number of sides and divide that into 360.

Don't know if the five pieces is really important to your design, but there is a neat trick if you want six sides. Draw the circle with a compass or tramel and without changing it, "step" it off around the perimeter of the circle and it will go exactly six steps. I'll leave you to figure the angle. (30*)

With five sides, I would draw the circle and then fiddle with the sompas until I got exactly five steps. Then draw in the five spokes and then figure how long to cut the pieces after drawing the inner circle.

Are you sure you want to accept this?

Gary Smyth

Why not just buy a wood wheel (which, by the way, since Egyptian times, most wood wheels have six or more spokes. (I did see a picture of a four spoke on one though)

CNC cut metal custom car wheels are a different ballgame.

You can Google five spoke wheel to check, however. Will a five spoke WOOD wheel hold up to weighted rolling stresses? What is the size of the hub? What is the size of the wheel rim inside diameter? If you are going to mortise the spokes remember that in addition to additional length the shoulders will need to match the curve of the outside of the hub, and the inside of the wheel rim. Wheelwrights use a heated metal rim with rapid cooling to shrink the rim and tighten the already tight wood spokes from the outside in. Elm has been a favorite for the stresses on the hub.

You can, of course drill and insert the spokes, but will they stay where you put them as with only five spokes they will have way more stress than say a Windsor chair back.

Lastly, for me, you could make a Carnival single piece five spoke wheel (maybe double up the thickness) and cut out the portions between the hub and wide rim.

No matter how you do it you will need a metal bushing at the axel to keep wear down at the critical connection point. With all the concerns, if you're committed, go for it,

a hard way and an easy way

John K Jordan

>>>...one half of 180 minus 72, or 54 degrees. The angle setting on a miter saw may be the complement of this angle, 90-54, or 36 degrees.

It might be bit easier if you consider that 1/2 the angle of the "pie slice" would be 36 deg, the angle to cut on the end of the board. But of course, there are multiple ways to get the same answer. (Which is great since that's a good way to check the logic and the arithmetic!)

As for the numbers:

Calculating the board length and width based on the width of the wheel rim would take a couple of steps. One way I can think of to get the total length of the of the board (the long side of the segment) is to calculate the chord tangential to the outer radius of the wheel using the pythagorean theorum, then calculate the width of the board with trig using the cosine of the cut angle and the rim width as the hypotenuse of a right triangle.

Instead of the math, one could use a big compass or trammel points to draw the wheel actual size (or maybe 1/2 size), step off the five segments, then measure the drawing to see what size board to use.

Or an extremely easy way: use a segment calculator. Woodturners who make segmented pieces figure out this for the ring on every layer. I bought software to calculate the segments for every layer of a shape I can draw, but there are free on-line calculators such as this one:

http://www.woodturnersresource.com/extras/projects/segmentcalc/index.html

BTW, if you use Win 10 there should be a scientific calculator hiding in the windows calculator under the menu in the upper left corner.

JKJ

I would just lay it out to make a pattern

Re: a hard way and an easy way

Larry

John , I like the easy way !

Thanks