not sure what to call this and has it been asked before?

[engineer one]

thinking about what evie had to say, and since crimbo is getting nearer.
when you make a jewelry box, it is sometimes nice to give it a
lid with angled sides.( have i written that properly?)

so how do you work out the angles in hand tool mode??
i realise they are compound, but is there a quick formula like doing
crown moulding etc. the same applies for instance with doing a box which has sides which taper in two directions, and on which you want to
put dovetails. what is the math?

im sure i know, just want to check
paul

 

[Anonymous]

I can't quite picture what you're asking? Not that I know the answer, but still.

evie

 

[engineer one]

sounds like me, i must learn about posting images here.

anyway straight sided box, but the lid is made of the same thickness material, but it leans in towards the middle, kind of like a pyramid, but without the top.

well frank have i know blown any credibility???

i could i know just plane the bottom edge at say 30 degrees, since i do that normally i bet it is a pipper when you are trying to do it for real.
then drop the pieces into the compound mitre saw and using electricity cut it (aargh!) :lol: but i wondered if there is a formula. all these guys who write must have come up with something but what and where?

now it should be clearer than mud.
paul

 

[Anonymous]

Paul

To me a straight sided box mean one with parallel sides.

I think you are trying to make a pyrmaid and cut the top off (effectively)

Basic trig should sort it. Treat each side as a right-angled triangle when viewing the box from the front (or sides).

You will know the distance from the outer edge of the side to the point where it reaches the box top (the base of the triangle) and also the perpendicular height of the box from base to bottom of lid and so use TAN theta = (Height/Base) to find the angle

The cut angle will be between the outer side of the wall material and the box base

The angle at the top of the inner wall of the side where the lid touches it will be the same

 

[engineer one]

i knew it was simpler than i thought, but you know you can make yourself think in too complicated a way, so thanks for simplifying it
tony.
question, but if you had one more plane then what would you wish for,
and anyway would you use it???(hammer)
paul

 

[Chris Knight]

Try this http://www.woodcentral.com/bparticles/m ... mula.shtml

 

[engineer one]

thanks chris that was the info i was looking for ideal site, and quick info.
paul

 

[MikeW]

Here's a link to a spreadsheet on my server for compound miters.

Best way to get it to your computer is to right-click on the url below and choose to Save Target As... and select a place on your computer.

http://www.wenzloffandsons.com/temp/compound_miters.xls

Mike
a math challenged individual

 

[devonwoody]

Engineer one.

If in trouble still I believe the ancient Egyptians new a thing or two about pyrmidical shapes. Unfortunately they didn't archive any info on the web.

 

[engineer one]

thanks again guys
its a b**ger about the egyptians, they even killed some of the engineers to stop them passing on the secrets.
thankfully you guys did not.
thanks mike will look later.
paul :lol: :wink: