help with angles on square bowl

[farley]

I am in charge of getting our club to donate bowls for the Food Bank in their annual "empty bowl" fundraiser.

Each year they raise money for the food bank-- raising awareness of the "empty bowl" that some people (have no food). They do this by having a luncheon where people pay to join. They are given a pottery bowl to show their support, but they eat out of paper bowls.

Last year I asked if they would like wooden bowl from our turning club. They were delighted and would not give them away as an entrance gift, but rather they joined the high-end glass/pottery bowl in the silent action. It went well, they were happy, the turners were happy-money was raised.

This year I want to include the "flat board" woodworkers in my area, so I would like to make and demo to the club that all bowls do not have to be turned. I made a scroll saw one cut with angles and now I would like to make another one using local pecan and mesquite.

My problem being I am not too bright when it come to figuring out angles and since I am limited in my wood, I thought I would ask for help.

pictures below show my new resawing jig for my band saw which worked like the cat's meow with the logs. and the wood.

the second pix. show kinda what I think I am attempting to do. But I just don't want a square box, I want the sides angled into the base.

All the wood has to be trimmed, but my sizes now are: pecan about 4 1/2 by 7---2 of these and mesquite about 5 by 20-- 3 each all about 5/8 thick.





thanks for the help

[JPG]

First you must decide how much to tilt the sides.

Then this becomes a compound miter problem.

First trim the 4 side pieces to a common height with parallel top/bottom.

The shortest piece determines the max width at the top.

Next decide the amount of 'tilt' on all 4 sides.

Then the corner miter cuts would be as follows.

Tilt....Table....Miter
5°.... 44.75°... 5(-)°
10°... 44(+)°.. 9.75(+)°
15°... 43(+)°.. 14.5(-)° << corrected

(+), (-) means slightly more/greater.

If square, all 4 sides the are same width. If rectangular, opposite sides are same width. The bottoms will be shorter than the tops. The insides will be shorter than the outsides. You will only get one chance to get them all correct, so pay attention to orientation when cutting.

The bottoms(and top?) would be cut to the tilt angle.

[fitzhugh]

I found this, which may also help...
http://jansson.us/jcompound.html

The page has calculators for what you want to cut and a number of similar cases, like more than 4 sides.

[JPG]

I found this, which may also help...
http://jansson.us/jcompound.html

The page has calculators for what you want to cut and a number of similar cases, like more than 4 sides.

Use the calculator. I believe the chart I used is tainted!!!

Indeed it is. 34 s/b 43. Post above corrected

[fitzhugh]

You still get a better grade for effort. And even more for checking your work.

[JPG]

You still get a better grade for effort. And even more for checking your work.

The chart I used was from SS!(but I think you were not referring to that)!;)

As for checking the bowl, I would suggest a trial run with cheaper materials.