[OpenSCAD] Anyone done anything on countersunk screw holes?

[MichaelAtOz]

Apparently according to wikipedia
<https://en.wikipedia.org/wiki/Countersink> , ISO Metric & Imperial screw
countersink are 90 degrees, while American UN is 82d.
I need a hole to wall mount a holder, but it needs to be flush for an item
to slide into the holder.
Hence a countersunk screw. Ideally one model that can be used world wide.

A ISO screw in a 82d hole is going to sit proud, unless a smaller screw is
used.
A UN screw in a 90d hole just has less surface contact, but at the thinner
part of the hole - so less secure.

Anyone know the specification of screw head size for a given screw size, ie
the red bit:
<Loading Image...>

Something like BOLTS, but SCREWS?

It's not holding a bridge, maybe I'm over thinking this?




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[nop head]

This company gives dimensions of all the screws it sells, e.g.:
http://www.pts-uk.com/Products/Woodscrews_Pozi_Countersunk_Woodscrews_Metric_A2/A79973025

Post by MichaelAtOz
Apparently according to wikipedia
<https://en.wikipedia.org/wiki/Countersink> , ISO Metric & Imperial screw
countersink are 90 degrees, while American UN is 82d.
I need a hole to wall mount a holder, but it needs to be flush for an item
to slide into the holder.
Hence a countersunk screw. Ideally one model that can be used world wide.
A ISO screw in a 82d hole is going to sit proud, unless a smaller screw is
used.
A UN screw in a 90d hole just has less surface contact, but at the thinner
part of the hole - so less secure.
Anyone know the specification of screw head size for a given screw size, ie
<http://forum.openscad.org/file/n15728/400px-Screw_head_cs.png>
Something like BOLTS, but SCREWS?
It's not holding a bridge, maybe I'm over thinking this?
-----
Newly minted Admin - PM me if you need anything, or if I've done something stupid...
Unless specifically shown otherwise above, my contribution is in the
Public Domain; to the extent possible under law, I have waived all
copyright and related or neighbouring rights to this work. Obviously
inclusion of works of previous authors is not included in the above.
The TPP is no simple “trade agreement.” Fight it!
http://www.ourfairdeal.org/ time is running out!
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[Ezra Reynolds]

I normally just measure the screws I have at hand (shaft diameter, head
diameter, head width) and put notes in the OpenSCAD file as a comment
(where purchased, exact screw dimensions, etc.) That way anyone on
thingiverse who wants to build it can order something that should be
very similar. I also put all hardware-related things prominently marked
as variables at the top of the file so that it is easy to change.

I don't think you are going to find a universal screw that is readily
available worldwide; for most common applications it doesn't matter, for
niche and critical applications it is a special-order over the internet
anyway.

For example (in the US) wood screws for countersinking, even if they are
the same shaft diameter, often have different head profiles based on
different manufacturers. For 3D printing countersunk holes, it has been
problematic - different printers can sometimes be off by a millimeter,
especially on interior holes; this can make countersunk screws not sit
flush to the surface (using the same model, same screws, and different
3D printers).

Any commercial DIY products include the screws for this reason.

Post by nop head
http://www.pts-uk.com/Products/Woodscrews_Pozi_Countersunk_Woodscrews_Metric_A2/A79973025
Apparently according to wikipedia
<https://en.wikipedia.org/wiki/Countersink> , ISO Metric & Imperial screw
countersink are 90 degrees, while American UN is 82d.
I need a hole to wall mount a holder, but it needs to be flush for an item
to slide into the holder.
Hence a countersunk screw. Ideally one model that can be used world wide.
A ISO screw in a 82d hole is going to sit proud, unless a smaller screw is
used.
A UN screw in a 90d hole just has less surface contact, but at the thinner
part of the hole - so less secure.
Anyone know the specification of screw head size for a given screw size, ie
<http://forum.openscad.org/file/n15728/400px-Screw_head_cs.png>
Something like BOLTS, but SCREWS?
It's not holding a bridge, maybe I'm over thinking this?
-----
Newly minted Admin - PM me if you need anything, or if I've done
something stupid...
Unless specifically shown otherwise above, my contribution is in the
Public Domain; to the extent possible under law, I have waived all
copyright and related or neighbouring rights to this work. Obviously
inclusion of works of previous authors is not included in the above.
The TPP is no simple “trade agreement.” Fight it!
http://www.ourfairdeal.org/ time is running out!
--
http://forum.openscad.org/Anyone-done-anything-on-countersunk-screw-holes-tp15728.html
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[Mihail Vasiliev]

May be it would be a good idea to put imortant screw sizes into
well-commented variables, so anyone can adjust them to the screws he has?

Post by Ezra Reynolds
I normally just measure the screws I have at hand (shaft diameter, head
diameter, head width) and put notes in the OpenSCAD file as a comment
(where purchased, exact screw dimensions, etc.) That way anyone on
thingiverse who wants to build it can order something that should be very
similar. I also put all hardware-related things prominently marked as
variables at the top of the file so that it is easy to change.
I don't think you are going to find a universal screw that is readily
available worldwide; for most common applications it doesn't matter, for
niche and critical applications it is a special-order over the internet
anyway.
For example (in the US) wood screws for countersinking, even if they are
the same shaft diameter, often have different head profiles based on
different manufacturers. For 3D printing countersunk holes, it has been
problematic - different printers can sometimes be off by a millimeter,
especially on interior holes; this can make countersunk screws not sit
flush to the surface (using the same model, same screws, and different 3D
printers).
Any commercial DIY products include the screws for this reason.

Post by nop head
http://www.pts-uk.com/Products/Woodscrews_Pozi_Countersunk_Woodscrews_Metric_A2/A79973025
Apparently according to wikipedia
<https://en.wikipedia.org/wiki/Countersink> , ISO Metric & Imperial screw
countersink are 90 degrees, while American UN is 82d.
I need a hole to wall mount a holder, but it needs to be flush for an item
to slide into the holder.
Hence a countersunk screw. Ideally one model that can be used world wide.
A ISO screw in a 82d hole is going to sit proud, unless a smaller screw is
used.
A UN screw in a 90d hole just has less surface contact, but at the thinner
part of the hole - so less secure.
Anyone know the specification of screw head size for a given screw size, ie
<http://forum.openscad.org/file/n15728/400px-Screw_head_cs.png>
Something like BOLTS, but SCREWS?
It's not holding a bridge, maybe I'm over thinking this?
-----
Newly minted Admin - PM me if you need anything, or if I've done
something stupid...
Unless specifically shown otherwise above, my contribution is in the
Public Domain; to the extent possible under law, I have waived all
copyright and related or neighbouring rights to this work. Obviously
inclusion of works of previous authors is not included in the above.
The TPP is no simple “trade agreement.” Fight it!
http://www.ourfairdeal.org/ time is running out!
--
http://forum.openscad.org/Anyone-done-anything-on-countersunk-screw-holes-tp15728.html
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[nop head]

Countersunk screws are particularly tricky with 3D printed parts. If they
are vertical then you need to take into account the staircase effect if you
want them to sit flush, which depends on the layer height. I always use
poly_cylinders when I need accurate holes but this would need a poly_cone.
In practice they don't have infinitely sharp edges so you also need about
1mm of straight sided counter-bore above the cone.

If they are horizontal then it gets even more complicated with the
staircase and they tend to split the layers apart if you tighten them too
much. For that reason I use counter_bored pan heads in plastic parts.

Post by Mihail Vasiliev
May be it would be a good idea to put imortant screw sizes into
well-commented variables, so anyone can adjust them to the screws he has?
I normally just measure the screws I have at hand (shaft diameter, head

Post by Ezra Reynolds
diameter, head width) and put notes in the OpenSCAD file as a comment
(where purchased, exact screw dimensions, etc.) That way anyone on
thingiverse who wants to build it can order something that should be very
similar. I also put all hardware-related things prominently marked as
variables at the top of the file so that it is easy to change.
I don't think you are going to find a universal screw that is readily
available worldwide; for most common applications it doesn't matter, for
niche and critical applications it is a special-order over the internet
anyway.
For example (in the US) wood screws for countersinking, even if they are
the same shaft diameter, often have different head profiles based on
different manufacturers. For 3D printing countersunk holes, it has been
problematic - different printers can sometimes be off by a millimeter,
especially on interior holes; this can make countersunk screws not sit
flush to the surface (using the same model, same screws, and different 3D
printers).
Any commercial DIY products include the screws for this reason.

Post by nop head
http://www.pts-uk.com/Products/Woodscrews_Pozi_Countersunk_Woodscrews_Metric_A2/A79973025
Apparently according to wikipedia
<https://en.wikipedia.org/wiki/Countersink> , ISO Metric & Imperial screw
countersink are 90 degrees, while American UN is 82d.
I need a hole to wall mount a holder, but it needs to be flush for an item
to slide into the holder.
Hence a countersunk screw. Ideally one model that can be used world wide.
A ISO screw in a 82d hole is going to sit proud, unless a smaller screw is
used.
A UN screw in a 90d hole just has less surface contact, but at the thinner
part of the hole - so less secure.
Anyone know the specification of screw head size for a given screw size, ie
<http://forum.openscad.org/file/n15728/400px-Screw_head_cs.png>
Something like BOLTS, but SCREWS?
It's not holding a bridge, maybe I'm over thinking this?
-----
Newly minted Admin - PM me if you need anything, or if I've done
something stupid...
Unless specifically shown otherwise above, my contribution is in the
Public Domain; to the extent possible under law, I have waived all
copyright and related or neighbouring rights to this work. Obviously
inclusion of works of previous authors is not included in the above.
The TPP is no simple “trade agreement.” Fight it!
http://www.ourfairdeal.org/ time is running out!
--
http://forum.openscad.org/Anyone-done-anything-on-countersunk-screw-holes-tp15728.html
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[MichaelAtOz]

Thanks all.

For posterity this
<http://file.seekpart.com/keywordpdf/2011/3/22/20113228573866.pdf> gives
dimensions for metric & a UN (I'm assuming from the 82d angle) countersunk
screws of various types as the DIN standards.



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Newly minted Admin - PM me if you need anything, or if I've done something stupid...

Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.

The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out!
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[MichaelAtOz]

This is a handy reference too, one you have a reference - click in the boxes.
http://www.fasteners.eu/standards



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Unless specifically shown otherwise above, my contribution is in the Public Domain; to the extent possible under law, I have waived all copyright and related or neighbouring rights to this work. Obviously inclusion of works of previous authors is not included in the above.

The TPP is no simple “trade agreement.” Fight it! http://www.ourfairdeal.org/ time is running out!
--
View this message in context: http://forum.openscad.org/Anyone-done-anything-on-countersunk-screw-holes-tp15728p15741.html
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