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Re: bends

FH
Father Horton
Thu, Jul 15, 2021 6:57 PM

This is really rough, and you'd obviously need more points/arcs, but this
is what I had in mind:

intersection() {
linear_extrude(10) polygon([[0, -1], [10, -3], [20, 0], [10, 3], [0,
1]]);

translate([0, 5, 5])
rotate([0, 90,- 90]) linear_extrude(10) polygon([[0, 0], [0, 1], [-1,

10], [0, 20], [1, 20], [0, 10]]);
};

On Thu, Jul 15, 2021 at 1:30 PM Ron Wheeler via Discuss <
discuss@lists.openscad.org> wrote:

---------- Forwarded message ----------
From: Ron Wheeler rwheeler@artifact-software.com
To: discuss@lists.openscad.org
Cc:
Bcc:
Date: Thu, 15 Jul 2021 14:30:13 -0400
Subject: [OpenSCAD] Re: bends
Is there any particular reason for the nice rounded bends?

Are you building a replica that has to look exactly like the original or
something that only has the identical functionality?

If it only has to be functional, you also have opportunity to reinforce
key areas in ways that would be difficult for a blacksmith.

If it has to be identical in appearance, you should be able to assemble
cubes (straight sections) and arcs of cylinders given the dimensions (or
your revised dimensions) on the 2D drawing to make the desired 3D shape.

On 2021-07-15 11:55 a.m., Gene Heskett wrote:

On Thursday 15 July 2021 09:04:42 Ray West wrote:

Hi,

I have a tapered straight lever, given by

module st_lever(){

  pl= [
    [2,0,-2],[92,0,-1],[92,0,1],[2,0,2],
    [2,-1,-2],[92,-1,-1],[92,-1,1],[2,-1,2]];
  fl=[
   [0,1,2,3],
   [4,5,1,0],
   [7,6,5,4],
   [5,6,2,1],
   [6,7,3,2],
   [7,4,0,3]];

polyhedron(pl,fl);

}

it has to be bent in a number of places.

  • It starts off as rotate ([0,0,-5]) st_lever() -

It then has to be bent // to the x axis at x=48.5 for a distance of
10.5, then back at 45 deg for 4 or 5 inches, then // to x axis again
at a -y distance of 1.25 from axis. (then a bit further on it is bent
down).

Is there another way of doing this, other than either calculating the
xyz values at each bend location and making the polygon more
complicated, or using difference or intersection with cubes, say, to
split the lever into sections and stitch them together in the desired
profile? The attached jpg is what I'm working from (I'm not worried
about the loop at the end, nor the exact dimensions, it has to 'look
right', however.)

Actually Ray, that looks like a job for a blacksmith. Once the square
drive on the end is milled, the rest of it looks like a job for a smith
wrench in artistic hands.

I did stuff like that in a past life 65+ years ago while pulling wrenches
& doing engine swaps, but haven't had gas bottles for my torch in nearly
that long.

Memory trigger: Last engine swap I did turned a ford wagon, your basic
grocery getter, into a concealed weapon.

Demo'ed once by getting trapped behind a loaded hay sled north of Norfolk
NE at 22 mph. I swung out and saw a hole in the on coming traffic on a 2
lane, swung back behind it to let 3 cars go by headed north, snapped to
the other lane as I gave it some good gulf, and noted as my passenger
door passed that john poppers front tires, that my speedo was up to 83
mph accompanied by still bawling Michelins. I had one of my kids onboard
with a penny stuck in his throat that was running out of time. National
55 days, but you did what you had to do. I did get him to the hospital
ER in time.

Cheers, Gene Heskett

--
Ron Wheeler
Artifact Software
438-345-3369rwheeler@artifact-software.com

---------- Forwarded message ----------
From: Ron Wheeler via Discuss discuss@lists.openscad.org
To: discuss@lists.openscad.org
Cc: Ron Wheeler rwheeler@artifact-software.com
Bcc:
Date: Thu, 15 Jul 2021 14:30:13 -0400
Subject: [OpenSCAD] Re: bends


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This is really rough, and you'd obviously need more points/arcs, but this is what I had in mind: intersection() { linear_extrude(10) polygon([[0, -1], [10, -3], [20, 0], [10, 3], [0, 1]]); translate([0, 5, 5]) rotate([0, 90,- 90]) linear_extrude(10) polygon([[0, 0], [0, 1], [-1, 10], [0, 20], [1, 20], [0, 10]]); }; On Thu, Jul 15, 2021 at 1:30 PM Ron Wheeler via Discuss < discuss@lists.openscad.org> wrote: > > > > ---------- Forwarded message ---------- > From: Ron Wheeler <rwheeler@artifact-software.com> > To: discuss@lists.openscad.org > Cc: > Bcc: > Date: Thu, 15 Jul 2021 14:30:13 -0400 > Subject: [OpenSCAD] Re: bends > Is there any particular reason for the nice rounded bends? > > Are you building a replica that has to look exactly like the original or > something that only has the identical functionality? > > If it only has to be functional, you also have opportunity to reinforce > key areas in ways that would be difficult for a blacksmith. > > If it has to be identical in appearance, you should be able to assemble > cubes (straight sections) and arcs of cylinders given the dimensions (or > your revised dimensions) on the 2D drawing to make the desired 3D shape. > > On 2021-07-15 11:55 a.m., Gene Heskett wrote: > > On Thursday 15 July 2021 09:04:42 Ray West wrote: > > > Hi, > > I have a tapered straight lever, given by > > module st_lever(){ > > pl= [ > [2,0,-2],[92,0,-1],[92,0,1],[2,0,2], > [2,-1,-2],[92,-1,-1],[92,-1,1],[2,-1,2]]; > fl=[ > [0,1,2,3], > [4,5,1,0], > [7,6,5,4], > [5,6,2,1], > [6,7,3,2], > [7,4,0,3]]; > > polyhedron(pl,fl); > } > > it has to be bent in a number of places. > > - It starts off as rotate ([0,0,-5]) st_lever() - > > It then has to be bent // to the x axis at x=48.5 for a distance of > 10.5, then back at 45 deg for 4 or 5 inches, then // to x axis again > at a -y distance of 1.25 from axis. (then a bit further on it is bent > down). > > Is there another way of doing this, other than either calculating the > xyz values at each bend location and making the polygon more > complicated, or using difference or intersection with cubes, say, to > split the lever into sections and stitch them together in the desired > profile? The attached jpg is what I'm working from (I'm not worried > about the loop at the end, nor the exact dimensions, it has to 'look > right', however.) > > Actually Ray, that looks like a job for a blacksmith. Once the square > drive on the end is milled, the rest of it looks like a job for a smith > wrench in artistic hands. > > I did stuff like that in a past life 65+ years ago while pulling wrenches > & doing engine swaps, but haven't had gas bottles for my torch in nearly > that long. > > Memory trigger: Last engine swap I did turned a ford wagon, your basic > grocery getter, into a concealed weapon. > > Demo'ed once by getting trapped behind a loaded hay sled north of Norfolk > NE at 22 mph. I swung out and saw a hole in the on coming traffic on a 2 > lane, swung back behind it to let 3 cars go by headed north, snapped to > the other lane as I gave it some good gulf, and noted as my passenger > door passed that john poppers front tires, that my speedo was up to 83 > mph accompanied by still bawling Michelins. I had one of my kids onboard > with a penny stuck in his throat that was running out of time. National > 55 days, but you did what you had to do. I did get him to the hospital > ER in time. > > Cheers, Gene Heskett > > > -- > Ron Wheeler > Artifact Software > 438-345-3369rwheeler@artifact-software.com > > > > > ---------- Forwarded message ---------- > From: Ron Wheeler via Discuss <discuss@lists.openscad.org> > To: discuss@lists.openscad.org > Cc: Ron Wheeler <rwheeler@artifact-software.com> > Bcc: > Date: Thu, 15 Jul 2021 14:30:13 -0400 > Subject: [OpenSCAD] Re: bends > _______________________________________________ > OpenSCAD mailing list > To unsubscribe send an email to discuss-leave@lists.openscad.org >