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Tutorial: Creating a Twisted Flat Bar in Alibre Design

HaroldL

Alibre Super User
After trying to create a twist in .25 X 1.00 bar with a Loft and struggling with guide curves to make the 1/4 turn twist I thought I'd try the Helical Boss tool. After working on that for a while and searching the forum for any information I came across an old post where @MilesH suggested a "cheat" for twisting a hexagon and it seems I was thinking the same. Long story short, I finished a tutorial using my flat bar example while trying to follow the suggestions/guidelines that @Max posted.

So, with thanks to @MilesH for confirming my thinking, here is the tut in PDF format. Comments and suggestions are welcome but don't beat it up too bad.;)

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Updated version uploaded 10/02/2021.
 

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  • Tutorial for Creating A Twisted Bar in Alibre Design_RevB.pdf
    3.1 MB · Views: 14
Last edited:

wsimonton

Senior Member
Here is a technique provided to me by Oldbelt. The three flat layers provide the shape and all one has to do is use a spline curve to connect the three layers at each corner.
 

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  • Twist Flat Bar.AD_PKG
    184.1 KB · Views: 13

bigseb

Alibre Super User
Nicely done.

I play around with this occasionally using 3D sketches and/or lofts but honestly its a proper time suck so it's Moi to the rescue. Still, hats off to your work here.
 

HaroldL

Alibre Super User
Here is a technique provided to me by Oldbelt. The three flat layers provide the shape and all one has to do is use a spline curve to connect the three layers at each corner.
Yup, and that's the same example that lead me to using the Helical Boss tool as I stated in my first sentence. Way too many 3D spline guide curves to get just right and then if you want to change the twist angle it's another brain racking session to set up the sketches and guide curves. With the helical boss tool it's a easy edit to change the angle and or number of twists.
 

bigseb

Alibre Super User
Just used your method to create a baffle for core temp regulation... not bad not bad...

001.jpg
 

HaroldL

Alibre Super User
Glad you all are finding the tutorial useful;
I uploaded a corrected version of the tutorial.
 

Cator

Member
Thanks Harold really very interesting! I had seen something but my project (done as a hobby) was born from reliefs made on a scale model made by a local craftsman and from direct experience with these floats that are used in a traditional festival of the my country of origin.These means are common to all agricultural civilizations coeval with the first industrial revolution and carry within them all the technical history of construction that came from the Romans who were the first to have the need and possibility to move goods and people for long distances. ..but that's another story
Regards
Francesco
 
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