metal weapons weren't uncommon in ancient times. they are stronger, more durable, and the weight packs more of a punch in blocking and striking. but they are oftentimes too heavy for most regular practitioners to use, especially on a regular basis, in battle, or to carry around all the time. (unless your name is General Guan with your Guan Dao)
as far as i know, the Two Short Rods have always more commonly been a wooden weapon. if a weapon is too heavy, it makes it hard to generate Jin without injuring oneself, unless one really was so strong and could prevent the weapon from tearing ligaments in the whipping motion.
short rods are a policeman's weapon, very much like a nightstick. the Chinese name is "Sha Shou Jian", which translates to "killing hands rods". this directly implies that Two Short Rods was designed for disarming opponents. traditionally, i recall hearing that the ends of the short rods were rounded, in a ball-like shape, because it allowed for cavity strikes and cavity press. Two Short Rods was never meant to kill, only to disarm, disable, or knock out an opponent. that's why there are no sharp edges to the short rods. the Sai is also similar in this fashion. the Sai is rounded as well, not sharp, and also has cavity attack applications.
there is a certain way to block with the short rods, or with any weapon actually. you are supposed to avoid meeting your opponent's strikes and weapon head-on, because that increases the chances of breaking it and/or severely damaging it. in fact, even with swords, sabers, staffs, and other weapons, you want to actually slide and file as much as possible in blocks, and neutralize attacks by redirecting your opponents energy, as opposed to just stopping them with brute-force. you can damage a sword, saber, or metal rods just the same if you don't do so. you especially damage a sword's blade by doing so, even if you do meet it with the dull, blocking portion of the blade. keep in mind also that in a freestyle battle, you would have the freedom of angle-stepping as you block (footwork), which also helps to minimize that impact. all you need is enough contact to execute your next technique, no more and no less. a large part also depends on the quality of your weapon versus the quality of your opponent's weapon. there actually are some really strong types of wood out there. but of course, there are limits with what wood can do when put up against metal.
i think i recall my father speaking before of a demo when he was a teenager and demonstrating a short rods versus staff form when he was still learning and training in Taiwan. especially with all the adrenaline pumping for the public demonstration, he had blocked too hard and actually did end up breaking his weapon. lesson being, in a real battle, that's your life, down the drain. i suppose there's also some lesson learned here in controlling your anxiousness and emotions, to keep a clear head and good focus. i think that's why this story was originally brought up.
i have not seen or heard of anybody who makes short rods. it might just be one of those weapons that has faded with history. it doesn't seem to be the most popular weapon out there, but there do seem to be many variants of it, as in the links you posted.
shorten urls by typing it this way (without the space in the beginning)
[ url=http://ymaaboston.com]YMAA Boston website[/url]
Nicholas C. Yang
President, YMAA International
Assistant Director, YMAA Retreat Center
http://ymaa-retreatcenter.org