80/20 Questions

I haven't worked with this aluminum profile yet, but I plan to build a traction loss base to attach my existing Simetik K2 cockpit on with a 5 dof actuator build.

I am looking at these 90 degree joint braces, which are surprisingly expensive on the site I was going to order my build from: https://www.vention.io/parts/296 $9 per! I would need like 30+ of these things thats insane.

Would something like this work just as well or would it not be strong enough? https://www.homedepot.ca/en/home/p.1-12x1-12-corner-bracket.1000150336.html

Also, I plan to use a lazy susan as the front pivot, but for the rear I was hoping to use something like these nylon transfer bearings, thoughts?

Extruded aluminum is just expensive. I have found your experiences to be about the same as mine.
The $9 angles may be a bit high but the finished product will look pro ,much easier to assemble and maybe stronger.
If you need 30 ask them for a discount...
One thing about Sims.
Commercial or DIY it is not cheap.
Steel square tube is a lot cheaper and is pretty easy to weld.
A good angle grinder helps erase your mistakes... lol
Steel is just heavy but cannot be beat for cost vs strength.
A 5 or 6 dof still costs $3k to $5k to build.
Crazy I know.

If you're willing to bore some holes in the extrusions, you could use anchor fasteners. Even if you use a pair of them at each joint it's still cheaper than using corner gussets, and according to the 8020 fastener application tests they provide a stronger connection than a single gusset for most forces.

I’ve been thinking if 80/20 is even necessary for what I need. Wouldn’t your standard 2x4 lumber be strong enough for a traction loss base to have a Simetik k2 cock with 4 actuators running on it?

I'm sure you could make it work with lumber instead; I think I've seen entire 6DOF systems here using wood framing. You might need to add some corner braces to make sure the joints don't flex, but even 8020 needs that in some cases.

My main concern with typical pine 2x4s would be warping. Pretty much anything I've ever bought off the shelf at a big box lumber store has gotten a bit of a twist or bend in it after bringing it home -- not that big a deal if it's going to be nailed/bolted into some larger structure that will help keep it straight, but if you're just going to build a rectangular frame from a few pieces it might be an issue. Higher quality lumber (or larger dimensions) might be worth considering.

8020 of course has the advantage that if you need to adjust the position of a fastener you just loosen, slide, and re-tighten, so it's easier to tinker with it. Lumber may require more planning to make sure the cuts and fasteners are done right the first time, but then again even if you have to make multiple attempts and throw away some scrap pieces it's probably still cheaper than extrusions.

You never really mentioned what size extrusion you were planning to use.
4040??
Anyway I ordered some stuff from this guy and saw these corners and thought about you..
https://www.ebay.com/itm/90-Degree-...bc:m:mho6K5cVOSgPWR-4gPHvnag&var=572560647191