I have some twisted square shafts. It is actually quite difficult to twist a bamboo shaft of decent stiffness without cracking it. Incredibly so.
1/8th inch square shafts, carefully split, cut, and gently planed from large diameter bamboo, with the edges just barely rounded...
can be twisted 360 degrees on an 8 inch shaft with an 80% survival rate.
The main problem is that with a manufactured skewer that is square, it is rarely perfectly straight and of perfectly consistent size down its length, which makes one part twist more than another, which leads to cracking. It is possible to improve the rate to 85-90% pass by using wet heat(
[email protected] F) and GREEN(aka not cured) bamboo. Also, the shafts need to be heated to almost 300 degrees without burning them, also quite difficult to do. It is also critical that they be heated near-perfectly consistantly. My favorite method is to use a metal tube, with a little bit of water in it, to hold the shafts. They are ready to twist when the water has been gone for 5 mins. NEVER CAP THE TUBE.
If you don't add the water, the shafts tend to crack.
They do spin very well though.