SpiderBots latest version seems to have strengthened the magnetic arms... so maybe they don't fly apart as easily.  But there isn't an upgrade to that one since they changed it a fair bit.  Also this way I can use the common RoStock carriage so other parts can easily be fitted on (like my waterblock https://www.youmagine.com/designs/triple-water-block).  Info on the arms can be found here: http://forum.seemecnc.com/viewtopic.php?f=36&t=2165&hilit=traxxas I used aluminum rods as tapping CF rod doesn't really work for me.