r.d. terramir terramircomputers at gmail.com
Sat Sep 8 16:20:07 EDT 2018

```I tried to look up involute as a function of openscad and besides a
gitub involute gears I couldn't really find anything is involute in
but I did think about something here I dunno if it would work but try
to follow this and maybe give me some suggestions .but I did get a
spiral together with this code the top is sort of inaccurate and I may
have to run a test print or two to tweak it(the z and y factors) but I
think this might just work. the spiral makes 4.5 revolutions but the
top is smushed so I used 1440 as in four revolutions so it wouldn't
effect the height of the bottom revolutions as much and those are the
ones that will have to go through the battery holder.

<code

for (i=[0:0.5:1440]){
translate([0,0,(i/60)])
rotate([90,0,i])
translate([8.75-(i/170),0,0])
cylinder(r=0.9, h=0.4, \$fn=32);
}

</code>
terramir
Respectfully,
R. Daniel Borkan
Los Angeles, CA 90057
C: (213) 271-6721
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On Sat, Sep 8, 2018 at 12:10 PM Rob Sherwood <rob.sherwood at gmail.com> wrote:
>
> I did something similar to this where I created a formula to place a
> sequence of n circles along a path, and then did a hull() around each
> adjacent pair of circles.  The function I was following was an
> involute curve but you should be able to reuse this technique for an
> arbitrary path, e.g., your spring.
>
> Here's the relevant code:
>
>                     for (i = [1: step: max_angle] ) {
>                         point = involute( width, i);        // replace
> this function with your own path function
>                         prev_point = involute( width, i - step);   // ditto...
>                         hull() {
>                             translate([ point[0], point[1], 0])
>                                 circle(d=circle_diam, center=true);
>                             translate([ prev_point[0], prev_point[1], 0])
>                                 circle(d=circle_diam, center=true);
>                         }
>                     }
>
> Hope this helps,
>
> - Rob
> .
> On Sat, Sep 8, 2018 at 12:00 PM r.d. terramir
> <terramircomputers at gmail.com> wrote:
> >
> > https://plus.google.com/+rdterramir/posts/UPXqFQjo5YS here is the spring and I would like to put it through the end of the 3d printed plastic battery holder anyone got any ideas on how to model this please
> > terramir
> >
> > On Sep 7, 2018 4:12 PM, "nop head" <nop.head at gmail.com> wrote:
> >>
> >> Good luck. I model battery springs with a cone.
> >>
> >> On Fri, 7 Sep 2018, 23:03 r.d. terramir, <terramircomputers at gmail.com> wrote:
> >>>
> >>> Ok I need to embed a spiral cutout. 17.25mm the biggest diameter  the
> >>> next about 14mm then 11.33 then 9.15. distance 6mm for the first 3
> >>> spirals then about 4mm although that end won't be in the plastic it's
> >>> the wide end. the wire diameter is 1.4mm. I need to know how I would
> >>> program this.
> >>>
> >>> terramir
> >>>
> >>> _______________________________________________
> >>
> >>
> >> _______________________________________________
> >>
> > _______________________________________________