Has anyone gone to a 10mm screw? I have a bunch of rack and pinion I was going to use on a 5ftx10ft table I was building with Star 35mm linear rails but I need to build a machine to build that one. I'm trying to get 48x48 travel out of C-Beam for a plasma cutter. I need 1500mm screws, which aren't sold in 8mm. Would 10mm still fit in the C-Beam?
I know you can fit the popular and common 1/2-10 acme 5 start screw in the c-beam with the right nut and turning the ends down to fit the c-beam end plate or make new endplates for a different bearing. I will grab links and the demo cad file I drew up when I get back to the house tonight.
On a side note, I ordered wheels and plates for the c beam, but forgot spacers. What spacers are needed for the wheels? All I can find is "6mm or 1/4". Well which is it?
In your case it doesn't really matter. I'd suggest going with 6mm spacers just in case you want to reconfigure it later back to use with 8mm screws.
To fit the 1/2-10 acme 5 start screw in the C-Beam rail you will need to use this nut "Here" It is the only nut I have found for the larger 1/2" lead screw that will (barely) fit in the space provided by the c-beam. You can then either have each end of the screw turned down from 12.7mm to 8mm to work within the stock OB end plates and bearings or you can use a larger bearing setup and make new end plates. For a 10mm 1.5mm pitch screw, you can purchase some MR16105-ZZ bearings to work with the stock OB end plates; Followed with this anti-backlash nut "Here" and be good to go.
@ mrarmyant: you won't find 10 mm screws in 48" lengths, simply because the span is too big for the diameter. for the kind of span you need, try from 16 mm and up. i use four Tr 16x3 mm single start screws for my z axis, and they came in 60" lengths. lots of manufacturers out there, roton screws, nook, etc. also, try not to mix metric and imperial. if your machine is metric, stay away from imperial screws. last but not least, if precision is what you need, go with small pitch single start screws. trapezoidal metric is a close match to acme screws, both are specially designed for converting motion as opposed to your regular bolt which you tighten with a nut.
Roton will sale 10mm x 2mm trapezoidal lead screws up to 144" long. Nut sure if Roton's nut will fit inside on the C-beam center space ( I have not modeled up any of their options ) I agree, If you are going to run metric screws run them thru out. If Imperial screws run imperial thru out. Keeps things nice and simple for setup / dialing in.. However if you are not concerned with fitting the screw "inside" the C-beam and are okay with mounting it on the outside of the plate you have a lot more options including affordable ball screws.
I found a source for TR8*8 rod from Canada that comes in 1500mm. Problem you might have is whip. You can help combat this by tensioning the acme rod instead of compressing it
