> Hi Roger > If the bed is made from cast iron you could use 1.2mm dissimilar rods but the localised distortion and the normalising would mean the bed would need to be machined and trued I personally would go with the epoxy filler I have used this and if it is the same stuff you can tap it and machine it as though it was metal the only thin I would say against it is the need for the surfaces to be clinically clean. > Hope this helps > Steve A good cleaning with brake cleaner with perchlorethane or trichloethane in it will remove all traces of oil so the epoxy will stick. Here in the States, the material of choice for this would be "J.B. Weld®" and it may be available in Old Blighty as well. Jesse the redneck MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.