My second router design

[Joe]

Thanks for you input, its great to hear what other people have to say

what you are saying about mounting the Y axis rails makes sense and I have not re designed it so that they are over each other. but during this I have changed the gantry design. It now uses 2 sections of 25 x 50 with an aluminum plate between them which is 126 x 725 x 16. My problem is that I am unsure weather to use aluminum bar or steel bar on the sections highlighted in red.

The only reason I can think about not using steel would be weight so I did some calculations to find a estimate of the whole Gantry weight and it came out to be 45kg using 5083 aluminum with a density of 2650 Kg/m3.

If I was to use steel it would be an extra 17.9 Kg onto the over all weight compared to only 8.7 if it was aluminum so that would be 17% heavier.

I don't know if this would make a noticeable difference as it would be heavier but it would defiantly be stiffer but would the aluminum be stiff enough on its own?