linear bearing spacing

[reefy86]

does the y axis have to match the x axis when spacing the bearings and is it measured from center to center or outer edge to outer edge? reason i ask is because from center to center my bearings on the x axis is 200mm with 300mm long plates bolted to 2 bearing blocks but if i match the y axis to the same distance it is making my z axis plates wide and so making the total width of the machine wider which i don't want.

Thanks again

[AndyUK]

does the y axis have to match the x axis when spacing the bearings and is it measured from center to center or outer edge to outer edge? reason i ask is because from center to center my bearings on the x axis is 200mm with 300mm long plates bolted to 2 bearing blocks but if i match the y axis to the same distance it is making my z axis plates wide and so making the total width of the machine wider which i don't want.

Thanks again

There is nothing to say that your X and Y bearings should be spaced equally, and you can measure the distance however you fancy. Obviously the farther apart they are the greater their ability to resist the twisting moment.

If it helps, my build has an outer edge to outer edge bearing distance of 270mm on X and 150mm on Y. As you say, any more and you lose significant amounts of travel.