3D printing a calculator stand

General discussion about calculators, SwissMicros or otherwise
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Jaymos
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Re: 3D printing a calculator stand

Post by Jaymos »

The stand looks great.
I just ordered mine.

The shipping cost is soooo unreasonable though.
Jaco Mostert
Elec Eng, South Africa
https://47calc.com C47 (s/n 03818 & 06199), WP43 (0015). In box: HP42S, HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; ex: FX702P, 11C, HP67 & HP85; iOS: 42s Byron, Free42+, WP31S/34S, HCalc.
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rudi
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Re: 3D printing a calculator stand

Post by rudi »

I had an idea: glue some neodynium magnets to the stand, such that the DM42 with it's metal casing will stick to the stand.
But nu, just tested with a magnet, either the casing is aluminum or another metal alloy, that isn't magnetic. I only felt a very weak magnetic attraction when testing with a rather large magnet, and that might have been from iron parts inside the calculator.
Perhaps glue some small neodynium magnets on the inside of the casing then?
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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Jaymos
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Re: 3D printing a calculator stand

Post by Jaymos »

rudi wrote:
Mon Aug 29, 2022 1:08 pm
I had an idea: glue some neodynium magnets to the stand, such that the DM42 with it's metal casing will stick to the stand.
But nu, just tested with a magnet, either the casing is aluminum or another metal alloy, that isn't magnetic. I only felt a very weak magnetic attraction when testing with a rather large magnet, and that might have been from iron parts inside the calculator.
Perhaps glue some small neodynium magnets on the inside of the casing then?
You actually made me get up and go fetch my stack of thin strong button-cell type magnets and I can confirm both my DM42 back covers are non-magnetic.

I think your idea is cool - you could stick two magnets to the inside of the back cover. And glue some on the 3D housing. I will try that when my 2 x stands arrive - I have enough of exactly these magnets:
Jaco Mostert
Elec Eng, South Africa
https://47calc.com C47 (s/n 03818 & 06199), WP43 (0015). In box: HP42S, HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; ex: FX702P, 11C, HP67 & HP85; iOS: 42s Byron, Free42+, WP31S/34S, HCalc.
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Walter
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Re: 3D printing a calculator stand

Post by Walter »

rudi wrote:
Mon Aug 29, 2022 1:08 pm
I had an idea: glue some neodynium magnets to the stand, such that the DM42 with it's metal casing will stick to the stand.
But nu, just tested with a magnet, either the casing is aluminum or another metal alloy, that isn't magnetic. I only felt a very weak magnetic attraction when testing with a rather large magnet, and that might have been from iron parts inside the calculator.
Perhaps glue some small neodynium magnets on the inside of the casing then?
The DM42 casing is made of stainless steel which in its most popular austenitic kind is not magnetic. :o Strong as steel, stainless, but doesn't work with magnets. Sorry. That's physics. 8-)

And while these magnets you mentioned are excellent for holding some thin material on a carbon steel surface, their magnetic force steeply decreases with growing distance, be it air or whatever non-magnetic matter else. That's physics again.
WP43 SN00000, 34S, and 31S for obvious reasons; HP-35, 45, ..., 35S, 15CE, DM16L S/N# 00093, DM42β SN:00041
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Jaymos
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Re: 3D printing a calculator stand

Post by Jaymos »

Walter wrote:
Mon Aug 29, 2022 1:57 pm
rudi wrote:
Mon Aug 29, 2022 1:08 pm
I had an idea: glue some neodynium magnets to the stand, such that the DM42 with it's metal casing will stick to the stand.
But nu, just tested with a magnet, either the casing is aluminum or another metal alloy, that isn't magnetic. I only felt a very weak magnetic attraction when testing with a rather large magnet, and that might have been from iron parts inside the calculator.
Perhaps glue some small neodynium magnets on the inside of the casing then?
The DM42 casing is made of stainless steel which in its most popular austenitic kind is not magnetic. :o Strong as steel, stainless, but doesn't work with magnets. Sorry. That's physics. 8-)

And while these magnets you mentioned are excellent for holding some thin material on a carbon steel surface, their magnetic force steeply decreases with growing distance, be it air or whatever non-magnetic matter else. That's physics again.
In my experience, a pragmatic solution of testing the efficacy without knowing the physical quantities like force and distance for a 'proper' answer, beats a scientific answer hands down.

And that comment, made me get up again to find the screwdriver and stack of magnets again ...

Answer will follow ;-)
Jaco Mostert
Elec Eng, South Africa
https://47calc.com C47 (s/n 03818 & 06199), WP43 (0015). In box: HP42S, HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; ex: FX702P, 11C, HP67 & HP85; iOS: 42s Byron, Free42+, WP31S/34S, HCalc.
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Jaymos
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Re: 3D printing a calculator stand

Post by Jaymos »

Jaymos wrote:
Mon Aug 29, 2022 4:26 pm
Walter wrote:
Mon Aug 29, 2022 1:57 pm
rudi wrote:
Mon Aug 29, 2022 1:08 pm
I had an idea: glue some neodynium magnets to the stand, such that the DM42 with it's metal casing will stick to the stand.
But nu, just tested with a magnet, either the casing is aluminum or another metal alloy, that isn't magnetic. I only felt a very weak magnetic attraction when testing with a rather large magnet, and that might have been from iron parts inside the calculator.
Perhaps glue some small neodynium magnets on the inside of the casing then?
The DM42 casing is made of stainless steel which in its most popular austenitic kind is not magnetic. :o Strong as steel, stainless, but doesn't work with magnets. Sorry. That's physics. 8-)

And while these magnets you mentioned are excellent for holding some thin material on a carbon steel surface, their magnetic force steeply decreases with growing distance, be it air or whatever non-magnetic matter else. That's physics again.
In my experience, a pragmatic solution of testing the efficacy without knowing the physical quantities like force and distance for a 'proper' answer, beats a scientific answer hands down.

And that comment, made me get up again to find the screwdriver and stack of magnets again ...

Answer will follow ;-)
The definitive answer is that 0.75 mm thickness magnets (Amazon link in my prior post):

1. ... that are mounted ON the inside feet indents do not fit, as the components press on the magnets.
2. ... that are mounted directly below the top feet on the lid do fit.
3. Indicative of practically how much relative force is available:
3a. Using 1 single magnet on the pencil (rigid beam) it attracts, but cannot lift the calculator's weight.
3b. Using 2 magnets stacked on the pencil, the single support shown can hold up the calculator (balanced on the far side edge as per photo).
4. Knowing that the stand does not require holding up of the calculator, but merely to keep it in place, a single magnet mounted on 4 support locations inside the cover, with matching single magnet on the stand will work to keep it in place. If you want to securely work upside down ( :mrgreen: :lol: :ugeek: ) I would double up on the number of magnets on the 4 stand side supports.
5. Note - the inside tape is only there to hold the magnet to prevent it falling onto the PCB and shorting some stuff while not held in place by the stand ;-)
6. A yeah - don't blame me if something goes wrong.
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Jaco Mostert
Elec Eng, South Africa
https://47calc.com C47 (s/n 03818 & 06199), WP43 (0015). In box: HP42S, HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; ex: FX702P, 11C, HP67 & HP85; iOS: 42s Byron, Free42+, WP31S/34S, HCalc.
rprosperi
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Re: 3D printing a calculator stand

Post by rprosperi »

Bravo Jaco, practical results are hard to argue with.

Thanks!
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
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Re: 3D printing a calculator stand

Post by H2X »

I'd consider magnetic tape on the outside of the bottom cover, avoiding the risk of touching the PCB altogether.

https://www.amazon.com/s?k=magnetic+tape
What is the metric tensor in imperial units?
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rudi
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Re: 3D printing a calculator stand

Post by rudi »

He - yes, mostly learning by doing or trial and error works great.
Magnetic tape also sounds like a good idea.
/Rudi

DM-42 (s/n 06999), HP-42S, HP-35s, HP-11c, HP-32SII (ex HP-41CV, ex HP-75C, ex HP-48G + a lot, really lot of a accessories)
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Re: 3D printing a calculator stand

Post by H2X »

rprosperi wrote:
Mon Aug 29, 2022 5:36 pm
Bravo Jaco, practical results are hard to argue with.

Thanks!
Those magnets must be quantum entangled. But wait, shouldn't that effect wear off after you observed them?

You didn't do all this work blindfolded? :lol:
What is the metric tensor in imperial units?
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