Kmart Grease Pot Supportscreen DIY 03/09/2007

[bmike]

formula is:

(radius 2 / base circumference) * 57.2957795

this takes the larger radius (radius 2, in inches) and divides by the desired base circumference (pot circumference + adder for base, in inches) and gives you a multiplier.
(i assumed this is radians)

multiply this by 57.2957795 to get degrees.
now you have the degrees between the ends of the arc to form the base circumference. the angle will form the match lines for the centerline of the seam. add extra to each side for some overlap.

you math and enginerd types can tell me if i'm wrong - but this seems to check out graphically. (i went to cutty pastey school, fwiw)

[english stu]

Thanks Zelph for the pictures and the movie ,real helpful. I need to do a bit of tweaking to get the right flame colour on my set up .

[Pure Mahem]

No clue about what a radian is never got to the CAD part of DDP. But I'm just guessing with what I know. R in all my formulas is the radius. Took some trig,pre calc and calc and crap like that but only remember geometry go figure. Guess what they say is true if you don't use it you lose it! HUGH, OMG! HONEY, we need to have woopee!

[bmike]

No clue about what a radian is never got to the CAD part of DDP. But I'm just guessing with what I know. R in all my formulas is the radius. Took some trig,pre calc and calc and crap like that but only remember geometry go figure. Guess what they say is true if you don't use it you lose it! HUGH, OMG! HONEY, we need to have woopee!

heh!

radian is simply when the radius = arc length
here's a great graphic from wickipedia:



for the math folks it is supposed to make life easier when doing trig and such, as you can just use radians instead of degrees. makes for cleaner formulas.
i never new. remembered it vaguely from way way back... had to look it up.

[zelph]

If I remember right there are six radians to the circumfrence. I'm workin on it!!!!!! In between stove stuff

[oops56]

If I remember right there are six radians to the circumfrence. I'm workin on it!!!!!! In between stove stuff

Its all greek to me just buy a big funnel cut to size

[Ridgerunner]

Its all greek to me just buy a big funnel cut to size

I like your logic, oops. NOW, to find a lightweight funnel that is big enough to support the grease pot and have enough material left to elevate the pot high enough off the ground Might just be easier to make one!

[bmike]

zelph -
i think there is an error in the original layout.
the radius should be determined and drawn through the points at the edge of the cone area, not the bottom of where the stove sits.

when you cut the curve to the radius shown in your drawing, the pot height will be slightly lower than anticipated... this may not be much, or even noticeable... but the geometer in me was bugged by slight errors in the construction of these. the tangent on the cone is longer than the vertical dimension. in the case of my drawing, by 1/8" or so.
see pdf and compare green line (new) to blue line (generated via your picture)

PDF

your original drawing generates the centerpoint for the arc correctly - but you then draw the correct radius to the vertical height of the stove / pot relationship. as this is a cone, the length of the line from top line of pot to bottom of cone needs to be the dimension of the line drawn from pot edge to cone edge. to correct simply adjust the radius to the outer points of the cone edge...

unless i'm missing something.

[Skidsteer]

I've done the math on cone projects but the easiest way by far is Oops method.

To expand on that concept let me offer my solution:

Go to the thrift store, find a cloth lampshade that matches your specs, and buy it for about 50 cents.

Cut it straight up the side and you have a pattern that can be reused many times.

[zelph]

Bmike, thanks for the headsup. I'll do a retake on the drawing and see what you refer to Hmmmmmm!!interesting.

Skids makes it sound a lot easier with the lamp shades