Using 8020 for LowRider 3 framing

My work table is trimmed with 4080 extrusion. At the moment, I’m just runnning my LowRider 3 on MDF that covers that extrusion. I’d like to run along the extrusion itself, so I have two or three questions.

  1. Has anyone done anything with aluminum extrusion yet?
  2. It would be nice to have t-slot mountable tube brackets, anyone done that yet?
  3. It would be nice to have t-slot mountable timing belt stops/tensioners, anyone done that yet?

I have seen the work for ‘C’ channel, which is great. I’m looking for similar usage of t-slot essentially.

I think there is still a version that uses wheels would they run the groove in the extrusion? Or maybe the bearing could have polymer printer wheels?

I was thinking of that. Yes, I could either run the wheels, or print TPU covers for the bearings. I could also just put a cover over the slot on the top, leaving only enough extrusion open at the ends to set the tensioner and stop.

That still leaves the slots down the sides to do other interesting things, like my track saw guide.

For the pipe side, I’m thinking the current bracket, with the pipe clip turned 90 degrees would be good enough. Then just use the hole for a screw to go into one of the extrusion nuts.

For the tensioner stop, I’ve already confirmed I can just widen the hole to 5mm, and stick a nut on the end, and that’s that.

worst case scenario, you fasten your spoilboard over top of the extrusion.

Yah, that’s what I’m currently doing. The extrusions are a non-factor. My posting here was to see if anyone had actually managed to incorporate them into a table design as yet.

I’ll just run my little experiments and see how it goes.

I’d think you’d want to avoid having wheels run in the grooves for fear of overconstraining something. If there’s any variance in the distance between the Y rail and the groove then it will either try to walk the wheel up the side of the groove or pull the truck up and off the rail. Best case it would flex things or cause Z height variation, worst case it’d derail something.

I think Doug and a few others have a bunch of posts on using unitstrut or metal hollow sections as the running surface for the LR3. As long as the bearings are running on a flat surface, I don’t think anything would particularly care. I did see a comment somewhere that metal-on-metal seems to result in chips/dust being compressed and building up whereas it seems to just get pushed out of the way on wood. No idea if that’s a commonly observed effect or not but would potentially be solvable by brushes or some kind of simple ‘scraper’ type

The wheels will 100% wear on the extrusions. My first printer was wheels on extrusion, and I had to replace the wheels like 3 times in its 4 year lifetime.

were those rubber/plastic/urethane wheels, or roller bearings?

I could place an insert into that top slot, and just run on top of that, whether steel/aluminum or plastic. That still allows me to at least use either the top slot or side slots to mount tensioners and stops.

I do have a piece of unistrut, and I printed out the thing that allows you to mount your blocks and tensioners on that. I think the extrusion gives me more options, especially for when the table is not actually doing its CNC thing, so I’m exploring that.