Hi Tom,
Check out the "NutsAndBolts" script.
http://moi3d.com/forum/index.php?webtag=MOI&msg=8682.117

(Threads are helical. There are many types of threads...)

- Brian

"B" would correspond to the "Bolt"
"A" would correspond to the "Nut"

The type of thread may depend upon the usage of the part.
Cross threading might be a consideration.
So some more engineering information may be needed...

Thanks Bemfarmer, I am having a look at this amazing script. Not finding out to what the "Chamfer" function applies to.

Hi Tom.

I made a slight modification, by commenting out the next to last two lines in function buildHex(.....), of the NutsAndBolts.htm file,
which leaves the nut as a cylinder:


// var hexShape = factory( 'polygon' , frame, frame.evaluate( innerRadius, 0, 0 ), 6, true);
// object = factory( 'booleanintersection', object, hexShape );

- Brian

(Chamfer rounds off the Hex Nut, and the top of the Hex Bolt head.)

It appears that forming the inner threads of the Nut cylinder will require Boolean difference of the shank.
This would not leave any clearance tolerance for a physical Nut and Bolt.

The intentional clearance, created between mating threads, is called the "allowance:"

https://www.fastenal.com/content/feds/pdf/Article%20-%20Screw%20Threads%20Design.pdf

(I recall that the galvanized bolts at Home Depot have "looser" threads.)

http://rick.sparber.org/nbo.pdf
http://rick.sparber.org/spt.pdf

- Brian

Very helpful, Brian ! I will modify the script and go through the PDF, which seems to be easily understandable. Thank you very much, I appreciate your help !