20 Set Black 4040 Series Aluminum Extrusion Profile Connector, Includes 1pc Wrench, 20pcs 3540 Corner Bracket, 40pcs M8 T-Slot Sliding Nuts and Hex Screw Bolt for 20S Aluminum Rail Accessories

I’m really impressed with the quality of this PETOX Aluminum Extrusion Connector Set. Usually, when you buy these bulk hardware kits, you expect a few bunged-up threads or missing pieces, but everything in this 30-set pack was spot on. The black finish on the corner brackets is nice and consistent, which makes my 2020 frame build look much more high-end than the raw silver ones. The included T-nuts slide smoothly into the rails without jamming, and having the right size wrench included in the box meant I could get straight to work. For the price, it’s a massive time-saver for anyone doing DIY 3D printer or sim rig projects.

I use 4040 aluminum to build a roof rack on my van. This corner bracket is very rigid. I like it.

Exactly what I needed

I got the "20 Set Black 4040 Series with M8 screw nut" and both brackets and 8mm bolts were fine; however, the T-nuts were way too wide at the bottom of the nut to fit any of my 4040 extruded tubing. I ended up using separately purchased carriage bolts and nylon-insert nuts that I had on hand. Seller contacted me to correct for the error. This would have been five-stars if the nuts where correct, I gave 4-stars because rest of product was rock on and seller actually cared.

These worked perfectly for all the inside corners on my 10-inch equipment rack using 2020 extrusion. Combined with an outside gusset, the joints are very strong and don't interfere with equipment mounting. There is enough slop in the oval holes to allow alignment, then they hold tight. Glad to have this in my 2020 inventory.

Solid and sturdy worked for my custom drawer system

Muy buen producto, recomendable

The 90s work great. But all the hardware started rusting within a month.