Brian, Imran -- I think both your suggestions are great, will definitely extend the extrusion for some added support and exploring more bearing options. I like these bearings because I'm lazy and I didn't want to machine anything more than I needed. I've been learning Fusion 360 (it is a pain in the butt) with my little mill and I have a new found appreciation for machinists & their patience.?
Dave -- I have used 80/20 since my first CNC router build back some 7 yrs ago and fell in love with them, so while it seems I have a lot of them laying around I really just order what I need direct from them, on demand. Their service and packing are impeccable and I almost always find what I need from their eBay store at reasonable rates. Yes, costly but compared to having to powder coat, wire brush, and weld steel, I think I end up ahead in terms of labor saved. I think I assembled the arm in my design in like 15 - 20 minutes, which is a big savings.?
Sang Luu