Ah good stuff Tom I need to go visit my local steelholder they are a good set of guys so hopefully they will be able to source me some. If not though I shall take that spare stuff you have and add it to the parts collection :)

These are the linear carriages I am looking at, they are finelineautomation ones and are a nice compact simple unit. I need to change the hole arrangement around to get them to bolt up to my aluminium extrusion for the gantry mount I am thinking of one rolling on the top and another rolling on the bottom of a sheet of CDS or possibly along a sheet of oilon plastic I need to check the rigidity of it but it is a self lubricating HDPE plastic. that should give me a rock solid gantry and hoefully belt driven should be able to shift it's weight around quite rapidly.