flattening a frustum
10-21-2003, 09:15 AM
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flattening a frustum
OK fellas,
what's teh formula / trick to drawign out a frustum - making a flat pattern, to be cut from whatever.... I have a few rocket ideas, and need a transition from one tube diameter, to another.
(For the techies, no, it won't be a 'strtuctural part', but a covering piece to give a graceful transition. the main joint will be with rings; the smaller tube inserted into the larger tube by an appropriate amount, held in place with rings and / or spacers..)
A frustum is a cone, with the top chopped off.
What I'm after, is: Given a height, a base diameter, and a top diameter, how do you lay it out, to cut it out of 'flat stock'? How is the pattern developed and drawn to give you a template to cut out?
anything easy-ish?
what's teh formula / trick to drawign out a frustum - making a flat pattern, to be cut from whatever.... I have a few rocket ideas, and need a transition from one tube diameter, to another.
(For the techies, no, it won't be a 'strtuctural part', but a covering piece to give a graceful transition. the main joint will be with rings; the smaller tube inserted into the larger tube by an appropriate amount, held in place with rings and / or spacers..)
A frustum is a cone, with the top chopped off.
What I'm after, is: Given a height, a base diameter, and a top diameter, how do you lay it out, to cut it out of 'flat stock'? How is the pattern developed and drawn to give you a template to cut out?
anything easy-ish?
10-21-2003, 09:51 AM
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RE: flattening a frustum
10-21-2003, 12:43 PM
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RE: flattening a frustum
You could try here:
http://www.vatsaas.org/rtv/arsenal/b...struction.aspx
look under flattening frustrum,
or here:
http://www.tpub.com/content/construc...s/14251_63.htm
Ensignnolo
http://www.vatsaas.org/rtv/arsenal/b...struction.aspx
look under flattening frustrum,
or here:
http://www.tpub.com/content/construc...s/14251_63.htm
Ensignnolo
10-22-2003, 03:45 PM
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RE: flattening a frustum
I had a blast ("blast", get it?) once I stumbled across the video section of the site at http://www.vatsaas.org/rtv/
Interesting stuff.
Interesting stuff.
10-22-2003, 05:10 PM
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RE: flattening a frustum
Dr. Wogs:
Just for your general infirmation, "Flattening " your frustrum is referred to, in drafting, as "Developing" a surface.
Was used a lot in AC/Heating ductwork - imagine the layout for an air manifold with a single large inlet, tapering as each outlet branched off, and doing the layout for all the bits of sheet metal to form it. Including the intersection points and shapes.
Bill.
PS: Yes, before you ask, it can all be done by hand with no calculations at all. The course name when I went to school was "Descriptive Geometry," a fancy name for mechanical drawing. wr.
Just for your general infirmation, "Flattening " your frustrum is referred to, in drafting, as "Developing" a surface.
Was used a lot in AC/Heating ductwork - imagine the layout for an air manifold with a single large inlet, tapering as each outlet branched off, and doing the layout for all the bits of sheet metal to form it. Including the intersection points and shapes.
Bill.
PS: Yes, before you ask, it can all be done by hand with no calculations at all. The course name when I went to school was "Descriptive Geometry," a fancy name for mechanical drawing. wr.
10-22-2003, 07:20 PM
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RE: flattening a frustum
Hey Doc Wogs, do you know how long it has been since I heard the term "right conical frustrum"? Good god it has been over 25 years. You just made me feel reeeaaall old. Last I heard that was in high scool in plane and solid geometry. I feel ancient now LOL.
Mark Shuman
Mark Shuman
10-23-2003, 06:47 AM
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RE: flattening a frustum
Don't anybody feel bad...
When I first saw this thread, I thought the answer might be "...with a flustrum flattener".
It was a good lesson. (and again, some cool rocket videos)
When I first saw this thread, I thought the answer might be "...with a flustrum flattener".
It was a good lesson. (and again, some cool rocket videos)
10-23-2003, 09:42 AM
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RE: flattening a frustum
the 'Birthday Napkin rocket of the Apocalypse' was my favorite! way cool design
(we have two of our rocket launches on our site..)
Sorry to make you feel old. You're jsut as old as you feel!!!! (and you should see my Lego colection!!
)
A frustum is the propper word.. What would you have thought if I called it a 'cone with teh top chopped off' thanks all!!
I've been working w-a-a-a-y too long with Acad (and Mech desktop and Inventor) that a lot of teh 'old ways' are forgotten, and buried in a book!!
(we have two of our rocket launches on our site..)
Sorry to make you feel old. You're jsut as old as you feel!!!! (and you should see my Lego colection!!
)A frustum is the propper word.. What would you have thought if I called it a 'cone with teh top chopped off' thanks all!!
I've been working w-a-a-a-y too long with Acad (and Mech desktop and Inventor) that a lot of teh 'old ways' are forgotten, and buried in a book!!
10-25-2003, 07:11 PM
#11
RE: flattening a frustum
There are two ways to develop a pattern for the shape you want. The constructions are done with no caculator and just dividers(compass) and streight edge. Used to do these with sheet metal. The two methods I remember are "Radial line development" (preffered) and "Trianglulation" Get a book showing this from a library listed under HVAC duct design. The process is too complex to explain here.
