Re: Gear Making for a Toy Car
Yeah, you referred to a table and 1/2 x 13 is a UNC thread. But the
original poster tried that and it didn't fit. The UNC threading is still
used extensively in the US---I have a box full of 1/4-20, and #10 and #8
machine screws and basically zero metric screws---but I've never heard of
BSW before. I understand that outside the USA, things have gone mostly
metric, but when the original poster said "my screw is 1/2-12, a British
size" he was correct. It is a British size. Yes, maybe a legacy size, not
used in new work, but still a British size. So the folks who jumped in to
proclaim that the UK is metric, to deny that this screw size is
British----they were incorrect.
Note that making BSW threads is NOT just a conversion thing, because the
BSW threads have a 55 deg angle whereas UNC threads have a 60 deg angle.
There may be some other subtle differences in the thread profile, though
those differences may not be important, but I think if you want things to
fit well you need to use the correct angle, at least. So it's a little
more complicated to fabricate for printing that than a simple unit
conversion. (So in BOSL2's screw code I think you would need to construct
a custom profile to define the shape of the threads and use the generic
thread making module.)
On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss <
discuss@lists.openscad.org> wrote:
---------- Forwarded message ----------
From: Roger Whiteley roger.whiteley@me.com
To: discuss@lists.openscad.org
Cc:
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
Folks
I had to refer to a copy of Zeus Precision Tables, 1/2 x 13 is a Unified
Coarse (UNC) thread, the equivalent Unified Fine thread is 1/2 x 20. Or
Machinery's Handbook but I don't have a copy yet, its on the way from eBay.
The UNF/UNC threads were in very wide use in the automotive world - even
in the UK. UNF for nuts and bolts, UNC for threads in castings.
Making screws to fit each other was a challenge until Whitworth created
a standard table, I used to machine cut screws on my Myford lathe - but
only imperial, I think most engineers just use what comes naturally
these days if they grew up with imperial..
The interesting thing about the BSP thread is that the taper version is
self sealing, whereas the metric equivalent isn't, which is why BSP is
still in wide use today...
Provided the pitch is correct thread engagement will work fine if
there's enough clearance on the threads - so you can make a thread to
size in OpenSCAD and scale it down [or up] in X and Y in the slicing stage.
Making non-metric threads in OpenSCAD is just a conversion thing - so
its not a problem doing 1/2 x 13 :-) so its all good.
R.
---------- Forwarded message ----------
From: Roger Whiteley via Discuss discuss@lists.openscad.org
To: discuss@lists.openscad.org
Cc: Roger Whiteley roger.whiteley@me.com
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
On 2/8/23 08:59, Adrian Mariano wrote:
Yeah, you referred to a table and 1/2 x 13 is a UNC thread. But the
original poster tried that and it didn't fit. The UNC threading is
still used extensively in the US---I have a box full of 1/4-20, and #10
and #8 machine screws and basically zero metric screws---but I've never
heard of BSW before. I understand that outside the USA, things have
gone mostly metric, but when the original poster said "my screw is
1/2-12, a British size" he was correct. It is a British size. Yes,
maybe a legacy size, not used in new work, but still a British size. So
the folks who jumped in to proclaim that the UK is metric, to deny that
this screw size is British----they were incorrect.
Note that making BSW threads is NOT just a conversion thing, because the
BSW threads have a 55 deg angle whereas UNC threads have a 60 deg
angle. There may be some other subtle differences in the thread
profile, though those differences may not be important, but I think if
you want things to fit well you need to use the correct angle, at
least. So it's a little more complicated to fabricate for printing that
than a simple unit conversion. (So in BOSL2's screw code I think you
would need to construct a custom profile to define the shape of the
threads and use the generic thread making module.)
Similar to my building a buttress profile tooth, cutting it in hard
maple, then printing the nuts, which I do by first making the bolt and
subtracting it from the inside of the half nut. With a two start scheme,
both half nuts are identical. Changing that is a simple as creating the
new tooth profile, describing the 6 points. Wood strength enhanced by
having 12 teeth engaged in the nut.
On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
<discuss@lists.openscad.org mailto:discuss@lists.openscad.org> wrote:
---------- Forwarded message ----------
From: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>
To: discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>
Cc:
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
Folks
I had to refer to a copy of Zeus Precision Tables, 1/2 x 13 is a
Unified
Coarse (UNC) thread, the equivalent Unified Fine thread is 1/2 x
20. Or
Machinery's Handbook but I don't have a copy yet, its on the way
from eBay.
The UNF/UNC threads were in very wide use in the automotive world -
even
in the UK. UNF for nuts and bolts, UNC for threads in castings.
Making screws to fit each other was a challenge until Whitworth created
a standard table, I used to machine cut screws on my Myford lathe - but
only imperial, I think most engineers just use what comes naturally
these days if they grew up with imperial..
The interesting thing about the BSP thread is that the taper version is
self sealing, whereas the metric equivalent isn't, which is why BSP is
still in wide use today...
Provided the pitch is correct thread engagement will work fine if
there's enough clearance on the threads - so you can make a thread to
size in OpenSCAD and scale it down [or up] in X and Y in the slicing
stage.
Making non-metric threads in OpenSCAD is just a conversion thing - so
its not a problem doing 1/2 x 13 :-) so its all good.
R.
---------- Forwarded message ----------
From: Roger Whiteley via Discuss <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
To: discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>
Cc: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/
Well, since BOSL2 already has buttress profile threading supported it's
easier to do that than it would be to make BSW, for which there is no
support at all.
On Wed, Feb 8, 2023 at 9:43 AM gene heskett gheskett@shentel.net wrote:
On 2/8/23 08:59, Adrian Mariano wrote:
Yeah, you referred to a table and 1/2 x 13 is a UNC thread. But the
original poster tried that and it didn't fit. The UNC threading is
still used extensively in the US---I have a box full of 1/4-20, and #10
and #8 machine screws and basically zero metric screws---but I've never
heard of BSW before. I understand that outside the USA, things have
gone mostly metric, but when the original poster said "my screw is
1/2-12, a British size" he was correct. It is a British size. Yes,
maybe a legacy size, not used in new work, but still a British size. So
the folks who jumped in to proclaim that the UK is metric, to deny that
this screw size is British----they were incorrect.
Note that making BSW threads is NOT just a conversion thing, because the
BSW threads have a 55 deg angle whereas UNC threads have a 60 deg
angle. There may be some other subtle differences in the thread
profile, though those differences may not be important, but I think if
you want things to fit well you need to use the correct angle, at
least. So it's a little more complicated to fabricate for printing that
than a simple unit conversion. (So in BOSL2's screw code I think you
would need to construct a custom profile to define the shape of the
threads and use the generic thread making module.)
Similar to my building a buttress profile tooth, cutting it in hard
maple, then printing the nuts, which I do by first making the bolt and
subtracting it from the inside of the half nut. With a two start scheme,
both half nuts are identical. Changing that is a simple as creating the
new tooth profile, describing the 6 points. Wood strength enhanced by
having 12 teeth engaged in the nut.
On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
<discuss@lists.openscad.org mailto:discuss@lists.openscad.org> wrote:
---------- Forwarded message ----------
From: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>
To: discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>
Cc:
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
Folks
I had to refer to a copy of Zeus Precision Tables, 1/2 x 13 is a
Unified
Coarse (UNC) thread, the equivalent Unified Fine thread is 1/2 x
20. Or
Machinery's Handbook but I don't have a copy yet, its on the way
from eBay.
The UNF/UNC threads were in very wide use in the automotive world -
even
in the UK. UNF for nuts and bolts, UNC for threads in castings.
Making screws to fit each other was a challenge until Whitworth
created
a standard table, I used to machine cut screws on my Myford lathe -
but
only imperial, I think most engineers just use what comes naturally
these days if they grew up with imperial..
The interesting thing about the BSP thread is that the taper version
is
self sealing, whereas the metric equivalent isn't, which is why BSP
is
still in wide use today...
Provided the pitch is correct thread engagement will work fine if
there's enough clearance on the threads - so you can make a thread to
size in OpenSCAD and scale it down [or up] in X and Y in the slicing
stage.
Making non-metric threads in OpenSCAD is just a conversion thing - so
its not a problem doing 1/2 x 13 :-) so its all good.
R.
---------- Forwarded message ----------
From: Roger Whiteley via Discuss <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
To: discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>
Cc: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
On 2/8/23 10:07, Adrian Mariano wrote:
Well, since BOSL2 already has buttress profile threading supported it's
easier to do that than it would be to make BSW, for which there is no
support at all.
The BSW profile of a 55 degree angle is just another extruded polygon to
OpenSCAD. One 3 point polygon, scale to tpmm or tpi. Definitely not magic.
Biggest problem on a real lathe is shaping the cutting tool but if
you've a rotary table on the mill, even that is doable. Just takes a
while to shape the HSS or carbide cutter, with a CBN wheel. The std
advance angle is then set at 32.5 degrees in the std G76 canned gcode
cycle to cut threads. That is a most versatile canned routine, even to
cutting threads invented on the spot of very slow taper. My 2 lathe's
have several examples of that being used to grab the end of an 8mm ball
screw that is threaded clear to the end. In fact, a chip tool with a
diamond shape could be used.
Let your imagination out to play w/o a chaperon.
On Wed, Feb 8, 2023 at 9:43 AM gene heskett <gheskett@shentel.net
mailto:gheskett@shentel.net> wrote:
On 2/8/23 08:59, Adrian Mariano wrote:
Yeah, you referred to a table and 1/2 x 13 is a UNC thread. But the
original poster tried that and it didn't fit. The UNC threading is
still used extensively in the US---I have a box full of 1/4-20,
and #10
and #8 machine screws and basically zero metric screws---but I've
never
heard of BSW before. I understand that outside the USA, things have
gone mostly metric, but when the original poster said "my screw is
1/2-12, a British size" he was correct. It is a British size. Yes,
maybe a legacy size, not used in new work, but still a British
size. So
the folks who jumped in to proclaim that the UK is metric, to
deny that
this screw size is British----they were incorrect.
Note that making BSW threads is NOT just a conversion thing,
because the
BSW threads have a 55 deg angle whereas UNC threads have a 60 deg
angle. There may be some other subtle differences in the thread
profile, though those differences may not be important, but I
think if
you want things to fit well you need to use the correct angle, at
least. So it's a little more complicated to fabricate for
printing that
than a simple unit conversion. (So in BOSL2's screw code I think
you
would need to construct a custom profile to define the shape of the
threads and use the generic thread making module.)
Similar to my building a buttress profile tooth, cutting it in hard
maple, then printing the nuts, which I do by first making the bolt and
subtracting it from the inside of the half nut. With a two start
scheme,
both half nuts are identical. Changing that is a simple as creating the
new tooth profile, describing the 6 points. Wood strength enhanced by
having 12 teeth engaged in the nut.
On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
<discuss@lists.openscad.org mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>> wrote:
---------- Forwarded message ----------
From: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>>
Cc:
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
Folks
I had to refer to a copy of Zeus Precision Tables, 1/2 x 13 is a
Unified
Coarse (UNC) thread, the equivalent Unified Fine thread is 1/2 x
20. Or
Machinery's Handbook but I don't have a copy yet, its on the way
from eBay.
The UNF/UNC threads were in very wide use in the automotive
world -
even
in the UK. UNF for nuts and bolts, UNC for threads in castings.
Making screws to fit each other was a challenge until
Whitworth created
a standard table, I used to machine cut screws on my Myford
lathe - but
only imperial, I think most engineers just use what comes
naturally
these days if they grew up with imperial..
The interesting thing about the BSP thread is that the taper
version is
self sealing, whereas the metric equivalent isn't, which is
why BSP is
still in wide use today...
Provided the pitch is correct thread engagement will work fine if
there's enough clearance on the threads - so you can make a
thread to
size in OpenSCAD and scale it down [or up] in X and Y in the
slicing
stage.
Making non-metric threads in OpenSCAD is just a conversion
thing - so
its not a problem doing 1/2 x 13 :-) so its all good.
R.
---------- Forwarded message ----------
From: Roger Whiteley via Discuss <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>>
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>>
Cc: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:roger.whiteley@me.com mailto:roger.whiteley@me.com>>
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to
discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>
<mailto:discuss-leave@lists.openscad.org>
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/
<http://geneslinuxbox.net:6309/>>
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/
Just because something is a polygon doesn't mean that it's not work to
correctly describe the polygon. In particular, if you really want to get
BSW correct you need to include the correct radius rounding on the thread.
On Wed, Feb 8, 2023 at 2:50 PM gene heskett gheskett@shentel.net wrote:
On 2/8/23 10:07, Adrian Mariano wrote:
Well, since BOSL2 already has buttress profile threading supported it's
easier to do that than it would be to make BSW, for which there is no
support at all.
The BSW profile of a 55 degree angle is just another extruded polygon to
OpenSCAD. One 3 point polygon, scale to tpmm or tpi. Definitely not magic.
Biggest problem on a real lathe is shaping the cutting tool but if
you've a rotary table on the mill, even that is doable. Just takes a
while to shape the HSS or carbide cutter, with a CBN wheel. The std
advance angle is then set at 32.5 degrees in the std G76 canned gcode
cycle to cut threads. That is a most versatile canned routine, even to
cutting threads invented on the spot of very slow taper. My 2 lathe's
have several examples of that being used to grab the end of an 8mm ball
screw that is threaded clear to the end. In fact, a chip tool with a
diamond shape could be used.
Let your imagination out to play w/o a chaperon.
On Wed, Feb 8, 2023 at 9:43 AM gene heskett <gheskett@shentel.net
mailto:gheskett@shentel.net> wrote:
On 2/8/23 08:59, Adrian Mariano wrote:
Yeah, you referred to a table and 1/2 x 13 is a UNC thread. But
the
original poster tried that and it didn't fit. The UNC threading
is
still used extensively in the US---I have a box full of 1/4-20,
and #10
and #8 machine screws and basically zero metric screws---but I've
never
heard of BSW before. I understand that outside the USA, things
have
gone mostly metric, but when the original poster said "my screw is
1/2-12, a British size" he was correct. It is a British size.
Yes,
maybe a legacy size, not used in new work, but still a British
size. So
the folks who jumped in to proclaim that the UK is metric, to
deny that
this screw size is British----they were incorrect.
Note that making BSW threads is NOT just a conversion thing,
because the
BSW threads have a 55 deg angle whereas UNC threads have a 60 deg
angle. There may be some other subtle differences in the thread
profile, though those differences may not be important, but I
think if
you want things to fit well you need to use the correct angle, at
least. So it's a little more complicated to fabricate for
printing that
than a simple unit conversion. (So in BOSL2's screw code I think
you
would need to construct a custom profile to define the shape of
the
threads and use the generic thread making module.)
Similar to my building a buttress profile tooth, cutting it in hard
maple, then printing the nuts, which I do by first making the bolt
and
subtracting it from the inside of the half nut. With a two start
scheme,
both half nuts are identical. Changing that is a simple as creating
the
new tooth profile, describing the 6 points. Wood strength enhanced
by
having 12 teeth engaged in the nut.
On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
<discuss@lists.openscad.org mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>> wrote:
---------- Forwarded message ----------
From: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:roger.whiteley@me.com <mailto:roger.whiteley@me.com
To: discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:
Cc:
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
Folks
I had to refer to a copy of Zeus Precision Tables, 1/2 x 13
is a
Unified
Coarse (UNC) thread, the equivalent Unified Fine thread is
1/2 x
20. Or
Machinery's Handbook but I don't have a copy yet, its on the
way
from eBay.
The UNF/UNC threads were in very wide use in the automotive
world -
even
in the UK. UNF for nuts and bolts, UNC for threads in
castings.
Making screws to fit each other was a challenge until
Whitworth created
a standard table, I used to machine cut screws on my Myford
lathe - but
only imperial, I think most engineers just use what comes
naturally
these days if they grew up with imperial..
The interesting thing about the BSP thread is that the taper
version is
self sealing, whereas the metric equivalent isn't, which is
why BSP is
still in wide use today...
Provided the pitch is correct thread engagement will work
fine if
there's enough clearance on the threads - so you can make a
thread to
size in OpenSCAD and scale it down [or up] in X and Y in the
slicing
stage.
Making non-metric threads in OpenSCAD is just a conversion
thing - so
its not a problem doing 1/2 x 13 :-) so its all good.
R.
---------- Forwarded message ----------
From: Roger Whiteley via Discuss <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>>
To: discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:
Cc: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:roger.whiteley@me.com <mailto:roger.whiteley@me.com
Bcc:
Date: Wed, 8 Feb 2023 09:05:03 +0000
Subject: [OpenSCAD] Re: Gear Making for a Toy Car
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to
discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>
<mailto:discuss-leave@lists.openscad.org>
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/
<http://geneslinuxbox.net:6309/>>
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
On 2/8/23 16:51, Adrian Mariano wrote:
Just because something is a polygon doesn't mean that it's not work to
correctly describe the polygon. In particular, if you really want to
get BSW correct you need to include the correct radius rounding on the
thread.
Quite true, but I'll plead guilty to simplifying the polygon to probably
6 or 7 points even in that case. drawing it out on square graph paper
helps a lot. Then scale it to the size needed. I my case, I took
advantage of a small rn cutter cutter to give the needed fillet's,
matching the ability of a .4 nozzle in the printer.
On Wed, Feb 8, 2023 at 2:50 PM gene heskett <gheskett@shentel.net
mailto:gheskett@shentel.net> wrote:
On 2/8/23 10:07, Adrian Mariano wrote:
Well, since BOSL2 already has buttress profile threading
supported it's
easier to do that than it would be to make BSW, for which there
is no
support at all.
The BSW profile of a 55 degree angle is just another extruded
polygon to
OpenSCAD. One 3 point polygon, scale to tpmm or tpi. Definitely not
magic.
Biggest problem on a real lathe is shaping the cutting tool but if
you've a rotary table on the mill, even that is doable. Just takes a
while to shape the HSS or carbide cutter, with a CBN wheel. The std
advance angle is then set at 32.5 degrees in the std G76 canned gcode
cycle to cut threads. That is a most versatile canned routine, even to
cutting threads invented on the spot of very slow taper. My 2 lathe's
have several examples of that being used to grab the end of an 8mm ball
screw that is threaded clear to the end. In fact, a chip tool with a
diamond shape could be used.
Let your imagination out to play w/o a chaperon.
On Wed, Feb 8, 2023 at 9:43 AM gene heskett <gheskett@shentel.net
<mailto:gheskett@shentel.net>
<mailto:gheskett@shentel.net mailto:gheskett@shentel.net>> wrote:
On 2/8/23 08:59, Adrian Mariano wrote:
> Yeah, you referred to a table and 1/2 x 13 is a UNC
thread. But the
> original poster tried that and it didn't fit. The UNC
threading is
> still used extensively in the US---I have a box full of
1/4-20,
and #10
> and #8 machine screws and basically zero metric
screws---but I've
never
> heard of BSW before. I understand that outside the USA,
things have
> gone mostly metric, but when the original poster said "my
screw is
> 1/2-12, a British size" he was correct. It is a British
size. Yes,
> maybe a legacy size, not used in new work, but still a British
size. So
> the folks who jumped in to proclaim that the UK is metric, to
deny that
> this screw size is British----they were incorrect.
>
> Note that making BSW threads is NOT just a conversion thing,
because the
> BSW threads have a 55 deg angle whereas UNC threads have a
60 deg
> angle. There may be some other subtle differences in the
thread
> profile, though those differences may not be important, but I
think if
> you want things to fit well you need to use the correct
angle, at
> least. So it's a little more complicated to fabricate for
printing that
> than a simple unit conversion. (So in BOSL2's screw code
I think
you
> would need to construct a custom profile to define the
shape of the
> threads and use the generic thread making module.)
>
Similar to my building a buttress profile tooth, cutting it
in hard
maple, then printing the nuts, which I do by first making the
bolt and
subtracting it from the inside of the half nut. With a two start
scheme,
both half nuts are identical. Changing that is a simple as
creating the
new tooth profile, describing the 6 points. Wood strength
enhanced by
having 12 teeth engaged in the nut.
> On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
> <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>>> wrote:
>
>
>
>
> ---------- Forwarded message ----------
> From: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:roger.whiteley@me.com mailto:roger.whiteley@me.com>
> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>>>
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>>>
> Cc:
> Bcc:
> Date: Wed, 8 Feb 2023 09:05:03 +0000
> Subject: [OpenSCAD] Re: Gear Making for a Toy Car
> Folks
>
> I had to refer to a copy of Zeus Precision Tables, 1/2
x 13 is a
> Unified
> Coarse (UNC) thread, the equivalent Unified Fine
thread is 1/2 x
> 20. Or
> Machinery's Handbook but I don't have a copy yet, its
on the way
> from eBay.
>
> The UNF/UNC threads were in very wide use in the
automotive
world -
> even
> in the UK. UNF for nuts and bolts, UNC for threads in
castings.
>
> Making screws to fit each other was a challenge until
Whitworth created
> a standard table, I used to machine cut screws on my
Myford
lathe - but
> only imperial, I think most engineers just use what comes
naturally
> these days if they grew up with imperial..
>
> The interesting thing about the BSP thread is that the
taper
version is
> self sealing, whereas the metric equivalent isn't,
which is
why BSP is
> still in wide use today...
>
> Provided the pitch is correct thread engagement will
work fine if
> there's enough clearance on the threads - so you can
make a
thread to
> size in OpenSCAD and scale it down [or up] in X and Y
in the
slicing
> stage.
>
> Making non-metric threads in OpenSCAD is just a conversion
thing - so
> its not a problem doing 1/2 x 13 :-) so its all good.
>
> R.
>
>
>
> ---------- Forwarded message ----------
> From: Roger Whiteley via Discuss
<discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
> <mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>>>
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org <mailto:discuss@lists.openscad.org>>>
> Cc: Roger Whiteley <roger.whiteley@me.com
<mailto:roger.whiteley@me.com>
<mailto:roger.whiteley@me.com mailto:roger.whiteley@me.com>
> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>>>
> Bcc:
> Date: Wed, 8 Feb 2023 09:05:03 +0000
> Subject: [OpenSCAD] Re: Gear Making for a Toy Car
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email to
discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>
> <mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>>
>
>
> _______________________________________________
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<mailto:discuss-leave@lists.openscad.org>
<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/
<http://geneslinuxbox.net:6309/>
<http://geneslinuxbox.net:6309/
<http://geneslinuxbox.net:6309/>>>
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<mailto:discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>>
<mailto:discuss-leave@lists.openscad.org>
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/
<http://geneslinuxbox.net:6309/>>
_______________________________________________
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To unsubscribe send an email to discuss-leave@lists.openscad.org
<mailto:discuss-leave@lists.openscad.org>
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law respectable.
- Louis D. Brandeis
Genes Web page http://geneslinuxbox.net:6309/
Last year, round about August, iirc, i was feeling a bit screwy. I wrote
some code for generating threads, tapered or otherwise, for various
profiles. I've found my Whitworth profile. Can't remember how I
generated it.
On 08/02/2023 21:38, Adrian Mariano wrote:
Just because something is a polygon doesn't mean that it's not work to
correctly describe the polygon. In particular, if you really want to
get BSW correct you need to include the correct radius rounding on the
thread.
On Wed, Feb 8, 2023 at 2:50 PM gene heskett gheskett@shentel.net wrote:
On 2/8/23 10:07, Adrian Mariano wrote:
Well, since BOSL2 already has buttress profile threading
supported it's
easier to do that than it would be to make BSW, for which there
is no
support at all.
The BSW profile of a 55 degree angle is just another extruded
polygon to
OpenSCAD. One 3 point polygon, scale to tpmm or tpi. Definitely
not magic.
Biggest problem on a real lathe is shaping the cutting tool but if
you've a rotary table on the mill, even that is doable. Just takes a
while to shape the HSS or carbide cutter, with a CBN wheel. The std
advance angle is then set at 32.5 degrees in the std G76 canned gcode
cycle to cut threads. That is a most versatile canned routine,
even to
cutting threads invented on the spot of very slow taper. My 2 lathe's
have several examples of that being used to grab the end of an 8mm
ball
screw that is threaded clear to the end. In fact, a chip tool with a
diamond shape could be used.
Let your imagination out to play w/o a chaperon.
On Wed, Feb 8, 2023 at 9:43 AM gene heskett <gheskett@shentel.net
mailto:gheskett@shentel.net> wrote:
On 2/8/23 08:59, Adrian Mariano wrote:
> Yeah, you referred to a table and 1/2 x 13 is a UNC
thread. But the
> original poster tried that and it didn't fit. The UNC
threading is
> still used extensively in the US---I have a box full of
1/4-20,
and #10
> and #8 machine screws and basically zero metric
screws---but I've
never
> heard of BSW before. I understand that outside the USA,
things have
> gone mostly metric, but when the original poster said "my
screw is
> 1/2-12, a British size" he was correct. It is a British
size. Yes,
> maybe a legacy size, not used in new work, but still a
British
size. So
> the folks who jumped in to proclaim that the UK is metric, to
deny that
> this screw size is British----they were incorrect.
>
> Note that making BSW threads is NOT just a conversion thing,
because the
> BSW threads have a 55 deg angle whereas UNC threads have
a 60 deg
> angle. There may be some other subtle differences in the
thread
> profile, though those differences may not be important, but I
think if
> you want things to fit well you need to use the correct
angle, at
> least. So it's a little more complicated to fabricate for
printing that
> than a simple unit conversion. (So in BOSL2's screw code
I think
you
> would need to construct a custom profile to define the
shape of the
> threads and use the generic thread making module.)
>
Similar to my building a buttress profile tooth, cutting it
in hard
maple, then printing the nuts, which I do by first making
the bolt and
subtracting it from the inside of the half nut. With a two start
scheme,
both half nuts are identical. Changing that is a simple as
creating the
new tooth profile, describing the 6 points. Wood strength
enhanced by
having 12 teeth engaged in the nut.
> On Wed, Feb 8, 2023 at 4:05 AM Roger Whiteley via Discuss
> <discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>
<mailto:discuss@lists.openscad.org
mailto:discuss@lists.openscad.org>> wrote:
>
>
>
>
> ---------- Forwarded message ----------
> From: Roger Whiteley <roger.whiteley@me.com
mailto:roger.whiteley@me.com
> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>>
> To: discuss@lists.openscad.org
mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
> Cc:
> Bcc:
> Date: Wed, 8 Feb 2023 09:05:03 +0000
> Subject: [OpenSCAD] Re: Gear Making for a Toy Car
> Folks
>
> I had to refer to a copy of Zeus Precision Tables,
1/2 x 13 is a
> Unified
> Coarse (UNC) thread, the equivalent Unified Fine
thread is 1/2 x
> 20. Or
> Machinery's Handbook but I don't have a copy yet, its
on the way
> from eBay.
>
> The UNF/UNC threads were in very wide use in the
automotive
world -
> even
> in the UK. UNF for nuts and bolts, UNC for threads
in castings.
>
> Making screws to fit each other was a challenge until
Whitworth created
> a standard table, I used to machine cut screws on my
Myford
lathe - but
> only imperial, I think most engineers just use what comes
naturally
> these days if they grew up with imperial..
>
> The interesting thing about the BSP thread is that
the taper
version is
> self sealing, whereas the metric equivalent isn't,
which is
why BSP is
> still in wide use today...
>
> Provided the pitch is correct thread engagement will
work fine if
> there's enough clearance on the threads - so you can
make a
thread to
> size in OpenSCAD and scale it down [or up] in X and Y
in the
slicing
> stage.
>
> Making non-metric threads in OpenSCAD is just a
conversion
thing - so
> its not a problem doing 1/2 x 13 :-) so its all good.
>
> R.
>
>
>
> ---------- Forwarded message ----------
> From: Roger Whiteley via Discuss
<discuss@lists.openscad.org
mailto:discuss@lists.openscad.org
> <mailto:discuss@lists.openscad.org
mailto:discuss@lists.openscad.org>>
> To: discuss@lists.openscad.org
mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org
<mailto:discuss@lists.openscad.org>>
> Cc: Roger Whiteley <roger.whiteley@me.com
mailto:roger.whiteley@me.com
> <mailto:roger.whiteley@me.com
<mailto:roger.whiteley@me.com>>>
> Bcc:
> Date: Wed, 8 Feb 2023 09:05:03 +0000
> Subject: [OpenSCAD] Re: Gear Making for a Toy Car
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email to
discuss-leave@lists.openscad.org
mailto:discuss-leave@lists.openscad.org
> <mailto:discuss-leave@lists.openscad.org
mailto:discuss-leave@lists.openscad.org>
>
>
> _______________________________________________
> OpenSCAD mailing list
> To unsubscribe send an email to
discuss-leave@lists.openscad.org
mailto:discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/
http://geneslinuxbox.net:6309/>
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
mailto:discuss-leave@lists.openscad.org
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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, 1940)
If we desire respect for the law, we must first make the law
respectable.
- Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/>
_______________________________________________
OpenSCAD mailing list
To unsubscribe send an email to discuss-leave@lists.openscad.org
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