[TheForge] bar twisters

[gladish]

>
> Please explain how a solid piece shortens when twisted!
>
Hope you don't mind if I chime in on this one-

Think about what's happening when you twist square stock- You're taking a
piece of square, and in effect making it round. That is, if you gave it an
"infinite" number of twists, say 100 to the inch, you'd end up with a chunk
of fairly round stock the same diameter as the corner-to-corner (not
flat-to-flat) diameter of the square stock.

My tables show 1" square weighing 3.4 lbs. per foot, and 1 5/16" (corner to
corner) round at about 4.6 lbs. per foot.

Where does the extra bulk come from, if not shortening the bar?

Of course, in real life the diameter of a highly twisted bar isn't as great
as the diagonal thickness of the starting stock- it's more of an average, so
the shrinkage isn't as noticeable as all that on most hot twists.

Is that at least as clear as mud?
Andy G.