Watch out for this detail when buying extrusion from certain suppliers

I recently purchased a bunch of Series 20 Aluminum from a 80/20.net distributor in Canada called Rocky Mountain Motion Control. Being this is my first time dealing with a product like this, I did not realize that there were variations in the openings of the slot.

the aluminum i purchased has a slot opening of 5.26mm
after purchasing a ton of t-slot nuts, I realized they all have an extremely tight fit.. turns out most t-slot nuts you find on amazon, are for a 6mm opening, not 5.26mm.
This has been a little troublesome, as i've had to grind down the parts to make them fit, its very time consuming :/

Currently i've been searching Amazon, for some drop in T-nuts... and well, any type of nuts that are compatible with 80/20.net profile... sadly most products lack details, and simply state they are for "series 20", or for "2020" extrusion. some of them state they are for 6mm opening, and very few will include the detail "not compatible for 5.25mm opening"

That being said, the maker links that OpenBuilds sells fit just fine with the 80/20.net extrusion, the only down side to these, are that the set screws, and the hex key tend to round off, so be careful not to tighten too much.

Ill list here the parts i've tried with 80/20.net extrusion:

What works:

• Any Maker Links products from Open Builds (set screw and hex key easily rounds off)
• These hidden corner brackets (set screw and hex key easily rounds off)

Needed modification:

• Cast Corner Brackets (very tight fit, can force them into location, but far to much work to get them into the center of an extrusion, so I made some smaller on a grinder)

I have yet to find any drop in, or roll in nuts that can fit with these profiles, if anyone finds any, be sure to let me know

 

The set screws in the products i had linked above, one product from amazon, and the maker links openbuilds sells as well.




The profiles are no doubt different from openbuilds, in that they are not the "V-Rail" design. They do not allow for wheels to roll on them in the same mannor.
I chose these extrusions, as they are quite a bit cheaper than the "V-Rail" extrusions. And as i was only using to build a frame for my machine.
The part that is troublesome is simply that they don't accommodate the majority of T-slot nuts, drop in nuts, roll in nuts, spring loaded nuts, etc. that is found on Amazon.