Re: [Emc-users] OpenSCAD help needed

[Gene Heskett]

On Monday 15 March 2021 17:10:43 Dr. Nikolaus Klepp wrote:

> Anno domini 2021 Mon, 15 Mar 16:50:59 -0400
>
>  Gene Heskett scripsit:
> > Greetings all;
> >
> > I need help in understanding OpenSCAD's version of a variables
> > scope. I can assign an $XX variable at the top of a .scad file but
> > it doesn't get passed into subsequent constructs inside of {}
> > isolated functions's.
> >
> > So how is this done in OpenSCAD?
>
> Global variables are visible everywhere. e.g.:
>   $fn=180;
>   a=10;
This does not jib with what I have observed:
a=64.55
b=9.75
25 lines of code later, with no intervening use of a or b, both are now 
undefind.

cylinder([a, b, $fn=3); echo ( a, b);

(and both are undef. And openscad may, or may not crash and go away.

However, it ocurred to that I may be using some internal var names, and 
that was the secret, I can now adjust anything fron the top 10 lines of 
the file.  My test 60 tooth outer ring was a bit big so I now have 
another slightly smaller internal size being laid down. Test fit about 4 
tomorrow, I've not worked that out yet but the tsrget is going to be 
able to spec the tooth tip diameter, for both the inner wrong side out 
belt, and in a separate file, the outside diameter, and the tooth tip 
diameter, and everything else is autocalculated from those 3 
measurements,  Same idea for the bearing carrier that drives the inside 
of the flex belt. I know it can be done, the question is, can I do it?

Getting a semi-working handle on openscad will be a giant step for me.
So will finding the right temps for PETG, 250 is so hot its burning the 
stuff, looks like 230C for the nozzle is much better.

Thanks Nik. For giving me the elbow in the ribs to tackle it again.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] OpenSCAD help needed

[Dr. Nikolaus Klepp]

Anno domini 2021 Mon, 15 Mar 16:50:59 -0400
 Gene Heskett scripsit:
> Greetings all;
> 
> I need help in understanding OpenSCAD's version of a variables scope. I 
> can assign an $XX variable at the top of a .scad file but it doesn't get 
> passed into subsequent constructs inside of {} isolated functions's.
> 
> So how is this done in OpenSCAD?
> 
> Thanks all.
> 
> Cheers, Gene Heskett

I forgot: you should not use "$..." for variable names, only nomal C syntax.

Nik

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Re: [Emc-users] OpenSCAD help needed

[Dr. Nikolaus Klepp]

Anno domini 2021 Mon, 15 Mar 16:50:59 -0400
 Gene Heskett scripsit:
> Greetings all;
> 
> I need help in understanding OpenSCAD's version of a variables scope. I 
> can assign an $XX variable at the top of a .scad file but it doesn't get 
> passed into subsequent constructs inside of {} isolated functions's.
> 
> So how is this done in OpenSCAD?

Global variables are visible everywhere. e.g.:
$fn=180;
a=10;

Global variables are hidden by module definitions. Variabes in module 
definitions are only visible inside "module":
a=10;
echo(a);
module xxx(a,b) { echo(a); echo(b); }
xxx(99,88);
echo(b);

You can define local variable with "let" - globals are hidden, aso nested "led" 
hide variables:
a=10;
let (a=1, b=88) {
echo(a);
echo (b);
let (a=99) {
echo(a);
}
}
echo(a);
echo(b);

Last note: variables are not variabes, they are "write-once-variables". e.g. 
this will fail on newer versions od openscad, but will succeed on older 
versions (and gixe 2x 99):
a=10;
echo(a);
a=99;
echo(a);



Nik
> 
> Thanks all.
> 
> Cheers, Gene Heskett



-- 
Please do not email me anything that you are not comfortable also sharing with 
the NSA, CIA ...


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[Emc-users] OpenSCAD help needed

[Gene Heskett]

Greetings all;

I need help in understanding OpenSCAD's version of a variables scope. I 
can assign an $XX variable at the top of a .scad file but it doesn't get 
passed into subsequent constructs inside of {} isolated functions's.

So how is this done in OpenSCAD?

Thanks all.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Stamping tool guide column fastening

[andy pugh]

On Mon, 15 Mar 2021 at 19:05, Nicklas SB Karlsson  wrote:
>
> Then they have standard SMS that look perfectly
> smooth though marked with diameters Ds6 in one end and Dh4 in the other
> end, these are by no surprise cheaper, anyone have an idea how to fasten
> them?

Into a flanged foot, I would guess.

I probably know less than you on the subject, but when I made a gill
press tool recently I clamped it in a 3-jaw chuck.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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[Emc-users] Stamping tool guide column fastening

[Nicklas SB Karlsson]

Me being a complete novice on stamping tool. Anybody here know how to 
fasten guide column?


Supplier have different kinds, some are with larger foot and some clamps 
to hold them down. Then they have standard SMS that look perfectly 
smooth though marked with diameters Ds6 in one end and Dh4 in the other 
end, these are by no surprise cheaper, anyone have an idea how to fasten 
them?



Regards Nicklas Karlsson



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Re: [Emc-users] Probe recommendations.

[andrew beck]

Funny thing is they are only 3 hrs drive from my house.

I'm actually going through his town Friday.

But that's a pretty pricy probe I think.  For something that is not wireless

On Mon, 15 Mar 2021, 6:19 PM David Berndt,  wrote:

> I'm not going to say it's in the same cost range, but what about the
> Hallmark impact tolerant touch probe. ITTP?
> https://hallmarkdesign.co.nz/probe
>
>
>
>
> On Sun, 14 Mar 2021 17:13:17 -0400,  wrote:
>
> > Watch https://youtu.be/kwLydF4osc4 for an approach that I'm currently
> > playing with to reduce probe breakage .
> >
> > -Original Message-
> > From: Gerrit Visser 
> > Sent: March 14, 2021 4:33 PM
> > To: 'Enhanced Machine Controller (EMC)'  >
> > Subject: Re: [Emc-users] Probe recommendations.
> >
> > I am still at the 'tooling breakage' stage of cnc. So far only 1
> > Aliexpress
> > tip broken (CA$12 cost). I have some more on the way because I expect it
> > won't be the last broken one.
> > I have 2 Renishaw TP2's, they are surviving my inexperience so far. M2
> > threads.
> > Renishaw makes a sacrificial breakaway adapter, essentially a short
> > piece of
> > material with a groove. Male and female M4 threads at opposite ends. It
> > however costs more than you were spending on just the probe.
> >
> > Ken, this might be an option to try?
> > https://www.aliexpress.com/item/1005001421085958.html . If you make the
> > breakaway adapter then the more plentiful choices of M2 and M2.5 threaded
> > ones can come into play as well.
> >
> > gerrit
> >
> >
> > -Original Message-
> > From: ken.stra...@gmail.com 
> > Sent: March 14, 2021 3:37 PM
> > To: 'Enhanced Machine Controller (EMC)'  >
> > Subject: Re: [Emc-users] Probe recommendations.
> >
> > Yes, I use standard 4mm screw probes. Perhaps us$50 is "reasonable" but
> > I'm
> > just a hobbyist/retiree and I find that breakage due to stupidity
> > annoying.
> > I'd rather spend a similar amount on a decent bottle of wine!
> >
> >
> >
> >
> >
> > ___
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> >
> >
> >
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>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 15 March 2021 00:08:00 Sam Sokolik wrote:

> another painful video
>
> https://www.youtube.com/watch?v=U3e83H2mEyk

I would like to see it go clear around and back to zero. That lack of 
backlash is, IMO, very very impressive.

You got me going on one with a 30/1 ratio, about done with the answer to 
my question as I am also making a 58 tooth just to see it it has room 
for that much moton.  That would make it go 4 teeth per turn, if it will 
fit for the stationary gear.  First plastic from my 3d45 cleans up 
fairly well, and I've not made provisions for bolts yet as I intend to 
cut recesses in 2 face pieces of 1" thick alu, to fit the smooth outer 
rings and goop the stationary ring into the recess.  I will make a 
larger recess in the output side, with a 3d printed output cup that will 
fit the output ring with goop. With splines this big, I suspect the 
elcheapo roller skate bearings will do for the flex stretcher, as it 
looks like a larger bearing is going to result in more tooth to tooth 
drag, using two stacked, one on each side of the disk.

Speed of course is relative, this dremel printer is about 35% slower than 
cura's estimates.  Fun, and educational since this is being done in 
openscad. And I'm still got a long ways to go to be an openscad guru, if 
ever. Variable "scope" is I think being a problem. :(

> On Sat, Mar 13, 2021 at 8:40 PM Sam Sokolik  wrote:
> > Getting closer... I have to drill a bunch of holes in the face
> > plate... also have to preload the wheel bearing (grind a bit from
> > the center)
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210313_201227.jpg


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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