Spiral Formula?

[rsgpitt]

If you have seen AntDavisons Kettle electrolyzer, you will know what i'm going to attempt to make. I am convinced that his designt is the most efficient for the least amount of space. I'm varying his design by making two interwound spirals instead of 4. The thing i would like to know is how to calculate the distance between mounting holes, and since i dont have the $1000+ 3d studio max i can't use his way. I need to figure out where the holes will be along the spiral's. They should be spaced every 90 degrees, and it's so close with concentric circles, but stainless steel is not forgiving for even thousants of an inch. Does anyone know the formula?

[pertyfly]

Yeah, the formula is basically listed within his notes in his projects page. If you want, you can definitely go through the program he made (and clearly documented) by hand and do every calculation he made with a calculator and it will come to the same result. It's fairly straight forward there. It will give you the distance that EVERY hole is from the first, just like his program's output. Also, if you're REALLY nice to him, and ask him nicely he may feel so kind as to quickly run the numbers for you since he has the program made already. I'm not trying to volunteer him for that or anything. Just a suggestion!

[rsgpitt]

never mind guys i got it.

[AntDavison]

let me know the dimensions you are thinking of and i will run my program

my advice

... dont make the inner diameter less than an inch,

... with two plates as opposed to four, each plate will be much longer, and may exceed 50" / 60" a common stock length, also stable mounting will be a bit harder

... make a mockup in thin plastic sheet

... a feeler gauge will illustrate how flexible stainless shim is

... 2mm spacing is practically the smallest you should go for

I'm happy to help ANT

[rsgpitt]

[AntDavison]

[rsgpitt]

[rsgpitt]

[AntDavison]

[rsgpitt]

[AntDavison]

a few variations depending on how you cut your shim


the first set
two plates, each plate uses 25" of material per plate, od = 3"

the second set
two plates, each plate uses 50" of material per plate, od = 4"

the third set
four plates, each plate uses 25" of material per plate, od = 4"


infinite number of variations are possible, so just let me know your requirements ... i dont mind if you change your mind a dozen or so times


make a mockup in card or thin plastic sheet (i got mine from a place that makes plastic signage) first before committing to working with the shim, i suggest printing your layout out with an inkjet printer and then spraygluing the template to your card or plastic sheet

at 0.004", you should be able to cut it with a pair or scissors (0.004" is very thin, personally i would go as thick as i can), but drilling the holes accurately will be very difficult, thats why i went for laser cutting, talk to your laser cutters about how thin a material they can comfortably cut ... they will need to weight the shim to keep it flat during the cutting process

[rsgpitt]

Well having looked at feeler gauges, I think that .004-.006 is best, and i want to be able to drill/ bend it accurately, but do you think it will be to flimsy?.

For the first set, 2 25" spirals, are those holes the same for each one. I could make one template with that and it would work for both spirals?

[AntDavison]

i went for 0.010" myself, and that thickness was determined by how flexible the shim needed to be to bend by hand about the 1" plastic inner core, go for a fatter inner core and you can go for thicker material
0.020" was the thinnest stock stainless sheet (ie not shim) i could find, but this was too thick to bend easily by hand


yes, the distance between the mounting holes is the same for each plate, and in a two plate design, the plates are identical ... nice and simple


in a four plate design, you will appreciate that two of the plates are mounted 90 degrees from the other two, in which case two plate designs are necessary, all the mounting hole dimensions are the same, but the offsets are different ... take a close look at the third item of the spiral maths section of my project page, and you will see how the location of the mounting holes are different between the two plate designs .... i didnt make this clear enough to the laser cutters, and they firstly made me four plates the same, so i had to buy more material to get another two plates of the complimentary design made

to maximize the surface area, my preference is for a four plate design ... you can still wire the two pairs in parallel, and you end up with nice stable mounts/electrode posts

if you went for a four plate design, using 50" x .004" material the figures would be like this

turns = 4.5 ... ie each plate spirals around itself and the others 4.5 times/revolutions

i.d = 25.4mm = 1" as before


0.0mm in inches 0.0"
110.068mm = 4.3334"
214.992mm = 8.46426"
314.772mm = 12.3926"
409.407mm = 16.1184"
498.9mm = 19.6417"
583.249mm = 22.9626"
662.455mm = 26.0809"
736.519mm = 28.9968"
805.441mm = 31.7103"
869.222mm = 34.2213"
927.865mm = 36.5301"
981.368mm = 38.6365"
1029.74mm = 40.5408"
1072.97mm = 42.2429"
1111.08mm = 43.7431"
1144.06mm = 45.0415"
1171.92mm = 46.1385"
1194.68mm = 47.0346"

o.d. = 143.358mm / 25.4 = 5.64402"

this is getting close to fit snuggly within a 6" tube

[rsgpitt]

Ant, can you run the same 2 plate x 25 inches with .004, but with a .935 inch inner diamater. I measured my PVC pipe, and its a little smaller than one inch.

[AntDavison]

shim = 0.004" = 0.1016mm
washers = 1/8" = 3.1750mm
spacing = 3.2766mm

max length = 25" = 635mm

plates = 2

i.d. = 0.935" = 23.749mm

turns = 3.75

0.0mm = 0.0"
55.9912mm = 2.20438"
109.41mm = 4.30749"
160.257mm = 6.30934"
208.532mm = 8.20992"
254.235mm = 10.0092"
297.366mm = 11.7073"
337.926mm = 13.3042"
375.914mm = 14.7998"
411.332mm = 16.1942"
444.18mm = 17.4874"
474.457mm = 18.6794"
502.165mm = 19.7703"
527.305mm = 20.7601"
549.878mm = 21.6487"
569.884mm = 22.4364"

o.d. = 72.898mm = 2.87"


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http://www.oupower.com/index.php?dir=_O ... CN0030.JPG

when i built my kettle i didn't mount the plates hard up against the inner plastic core, but added a rubber spacer between the plastic core and the plates

if you were to use 1/8" (0.125") rubber spacers, then the figures would be as follows



i.d. = (0.935" + 0.125" + 0.125") = 1.185" = 30.099mm

turns = 3.5 (as turns = 3.75 would need a plate length > 644.6mm or 25.375")

0.0mm = 0.0"
58.4041mm = 2.29937"
114.236mm = 4.49748"
167.495mm = 6.5943"
218.183mm = 8.58986"
266.298mm = 10.4842"
311.842mm = 12.2772"
354.813mm = 13.969"
395.215mm = 15.5596"
433.043mm = 17.049"
468.302mm = 18.4371"
500.99mm = 19.724"
531.108mm = 20.9098"
558.658mm = 21.9944"
583.638mm = 22.9779"

o.d. = 75.9714 = 2.991"

you could fold the extra shim material to create electrode mounting posts

ANT