truncated teardrop countersink

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truncated teardrop countersink

nophead
Anybody know how to model this?

The hole and the counter-bore are truncated tear drops. How do I join
them with a 45 degree countersink that is also tear dropped?

It would be a loft operation in CoCreate.

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Re: truncated teardrop countersink

Giles Bathgate-2
Perhaps an inverse of the hole, and countersink can be made using 3d
convex hull?
and then subtract that from the block?

Regards

Giles

On 29 September 2011 22:23, nop head <[hidden email]> wrote:

> Anybody know how to model this?
>
> The hole and the counter-bore are truncated tear drops. How do I join
> them with a 45 degree countersink that is also tear dropped?
>
> It would be a loft operation in CoCreate.
>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://rocklinux.net/mailman/listinfo/openscad
>
>

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Re: truncated teardrop countersink

Whosawhatsis
Does this look right?

rotate([0, -90, 0]) intersection() {
        union() {
                cylinder(r1 = 0, r2 = 10, h = 10);
                intersection() {
                        rotate([45, 0, 45]) cube(20);
                        rotate([45, 0, -45]) cube(20);
                        rotate([0, -45, 0]) translate([0, -10, 0]) cube(20);
                }
        }
        cube(20, center = true);
}

On Thu, Sep 29, 2011 at 2:30 PM, Giles Bathgate
<[hidden email]> wrote:

> Perhaps an inverse of the hole, and countersink can be made using 3d
> convex hull?
> and then subtract that from the block?
>
> Regards
>
> Giles
>
> On 29 September 2011 22:23, nop head <[hidden email]> wrote:
>> Anybody know how to model this?
>>
>> The hole and the counter-bore are truncated tear drops. How do I join
>> them with a 45 degree countersink that is also tear dropped?
>>
>> It would be a loft operation in CoCreate.
>>
>> _______________________________________________
>> OpenSCAD mailing list
>> [hidden email]
>> http://rocklinux.net/mailman/listinfo/openscad
>>
>>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://rocklinux.net/mailman/listinfo/openscad
>

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Re: truncated teardrop countersink

Whosawhatsis
keep in mind that teardropping the countersink is purely aesthetic. If
the countersink angle is 45 degrees, it won't create an overhang angle
steeper than that.

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Re: truncated teardrop countersink

Triffid Hunter
In reply to this post by nophead
here's a present for you!

module teardrop2(r1 = 10, r2 = 5, h=5) {
        difference() {
                cube([r1, r1, h]);
                translate([r1 * sqrt(2), 0, 0]) rotate([0, 0, 45]) rotate([0,
-atan((r1 - r2) / h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2,
h * (r1)]);
                translate([r1, r1, 0]) rotate([0, 0, 90]) rotate([0, -atan((r1 - r2)
/ h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2, h * (r1)]);
                translate([r1, -r1, 0]) rotate([0, 0, 0]) rotate([0, -atan((r1 - r2)
/ h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2, h * (r1)]);
        }
        cylinder(r1 = r1, r2 = r2, h=h);
}

r1 must be > r2 at the moment

enjoy :)

On Fri, Sep 30, 2011 at 7:23 AM, nop head <[hidden email]> wrote:

> Anybody know how to model this?
>
> The hole and the counter-bore are truncated tear drops. How do I join
> them with a 45 degree countersink that is also tear dropped?
>
> It would be a loft operation in CoCreate.
>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://rocklinux.net/mailman/listinfo/openscad
>
>

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Re: truncated teardrop countersink

nophead
Thanks All,

I think a 3D hull would have been the easiest and most general solution to this type of problem, but hull is only 2D in the version I have.

Whosawhatsis' version looks good. I used Triifid's because it was easier to drop in. I tidied it up a bit:

module teardrop2(r1 = 10, r2 = 5, h=5) {
   slope = -atan((r1 - r2) / h);
   union() {
       rotate([0, 0, 45])
           difference() {
               cube([r1, r1, h]);
               translate([r1 * sqrt(2), 0, 0])
                   rotate([0, 0, 45])
                       rotate([0, slope, 0])
                           translate([0, 0, -r1])
                               cube([r1 * 2, r1 * 2, h * r1]);
               translate([r1, r1, 0])
                   rotate([0, 0, 90])
                       rotate([0, slope, 0])
                           translate([0, 0, -r1])
                               cube([r1 * 2, r1 * 2, h * r1]);
               translate([r1, -r1, 0])
                   rotate([0, 0, 0])
                       rotate([0, slope, 0])
                           translate([0, 0, -r1])
                               cube([r1 * 2, r1 * 2, h * r1]);
           }
       cylinder(r1 = r1, r2 = r2, h = h, $fn = 32);
   }
}

The tear-dropped version uses a little less plastic and has less overhangs, as well as looking nicer, but the original does print OK.


On 30 September 2011 00:53, Triffid Hunter <[hidden email]> wrote:
> here's a present for you!
>
> module teardrop2(r1 = 10, r2 = 5, h=5) {
>        difference() {
>                cube([r1, r1, h]);
>                translate([r1 * sqrt(2), 0, 0]) rotate([0, 0, 45]) rotate([0,
> -atan((r1 - r2) / h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2,
> h * (r1)]);
>                translate([r1, r1, 0]) rotate([0, 0, 90]) rotate([0, -atan((r1 - r2)
> / h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2, h * (r1)]);
>                translate([r1, -r1, 0]) rotate([0, 0, 0]) rotate([0, -atan((r1 - r2)
> / h), 0]) translate([0, 0, -r1]) cube([r1 * 2, r1 * 2, h * (r1)]);
>        }
>        cylinder(r1 = r1, r2 = r2, h=h);
> }
>
> r1 must be > r2 at the moment
>
> enjoy :)
>
> On Fri, Sep 30, 2011 at 7:23 AM, nop head <[hidden email]> wrote:
>> Anybody know how to model this?
>>
>> The hole and the counter-bore are truncated tear drops. How do I join
>> them with a 45 degree countersink that is also tear dropped?
>>
>> It would be a loft operation in CoCreate.
>>
>> _______________________________________________
>> OpenSCAD mailing list
>> [hidden email]
>> http://rocklinux.net/mailman/listinfo/openscad
>>
>>
> _______________________________________________
> OpenSCAD mailing list
> [hidden email]
> http://rocklinux.net/mailman/listinfo/openscad
>


fixing-block2.png (17K) Download Attachment