On Jul 20, 2012, at 9:09 PM, andy pugh wrote: > On 21 July 2012 03:47, Gene Heskett <ghesk...@wdtv.com> wrote: > >>>> A linear rail and several supports tied to the carriage and each other >>>> with string, utilising the pathetic performance of string in >>>> compression to advantage. > >> I have this mental picture of Andy, with the equivalent of a whole can of >> Skoal in his cheek, but its not Skoal, its his tongue. ;-) > > It was actually a serious suggestion, but described in a jocular way. > > If you had a set of plain bushes to suit the OD of the screw held in > brackets sliding on a linear rail adjacent to the screw, then they > could be pushed out of the way by the ballnut/carriage and others > could be dragged behind the carriage on chains/strings. Rather like > the cable loops follow a travelling crane.
Got it now, thanks for the explanation Andy! That seems like a great solution. The only thing I fear is that the strings, chains, or ties could get caught in the ballscrew somehow. In any event, it does add a whole other level of complexity that I am really hoping to avoid. For my table, I have two ball screws, one beside each rail. So I would need another two 3 meter rails with supports, multiple bearing blocks, etc. It looks like over a 10 foot span I have about 24mm (0.96 inches) of sag in the middle. So I guess my question is, do you really think I will need that? What is the worse case scenario? I imagine most systems have a little flex in their horizontal ballscrews, but I wonder how much is acceptable, and what the consequences of having more flex than what would be acceptable be. Thanks again, Jeshua Lacock Founder/Engineer 3DTOPO Incorporated <http://3DTOPO.com> Phone: 208.462.4171 ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
