machine beds

[Tenson]

Hi Jonathan,

I've gone for about 80mm spacing between each 40mm extrusion. There will be a cross brace at each end and in the middle.

I think putting HDPE strips on either side of the extrusions seems a good idea. That way I can still use the T nuts and also move the extrusions about to support different size parts. Do you think there is any advantage in using Tufnol, it can be harder wearing I guess.

[Jonathan]

I think putting HDPE strips on either side ... Do you think there is any advantage in using Tufnol, it can be harder wearing I guess.

Tufnol is stronger and has a higher coefficient of friction, which will both help with clamping. However, being a composite, it will cause *much* more wear to the cutters when it gets cut. There's some good data here:

http://www.directplasticsonline.co.uk/graphs.html

Acetal is good since it machines so easily (but it's more expensive). When the cutter breaks through it's unlikely to be going the correct speed or feedrate for cutting the bed material, so ideally you need something that cuts over a wide range of conditions.