Was about to get a toy- then I did some research...

**Boyan Silyavski** · 05-02-2020

Originally Posted by Juranovich

I've planned on using a 250mm span between the outer ends of the square linear rail carriages and as it stands right now the arms would look like the blue lines in your sketch (though if cog is centered with centre of carriages the bit would fall outside or just on the outer edge of the front carriage). For reference the alu extrusions are 45x90.

It does not matter as far as you use Hiwin 20 size or comparable rails. You could offset al gantry rail to the back, to compensate a bit for this. As Dean says look at other build for inspiration and to figure the details.

I will not tire to say that machine is as strong as its weakest point, so do not overbuild / did i just say that

/ just take care not to have weak details