McMaster Carr is pretty great if you're American.

For the rest of us, there's Misumi!

They're both great! Mcmaster is the greatest website of all time. Sometimes the premium is 200% above other sources, but nobody cares because they can save so much time using Mcmaster. Misumi's configurable products that are machined to order are also a gamechanger, particularly on the Japanese site which has a lot wider variety. And they are hiring robotics engineers which should give interesting results.

MC could really use a shipping estimator. I remember ordering a $10 thing and getting charged $40 after shipping, which I didn’t m or would happen until after it shipped. Other than that I agree.

To add to the “greatest website of all time” aspect, they provide STEP files of a ton of those parts (maybe all of them?). When you’re drawing up a project like the OP’s in CAD, you can import the STEP file of the parts from McMaster and verify fit right there. If you’re using Fusion 360, there’s a button right in the app to browse McMaster and download the model!

And... if you need a part with a particular shape but not necessarily the strength of metal... shhhh... you can just 3D print it yourself from the STEP file.

It's a good website. It looks like they finally support tabbed browsing, but a less rigidly-enforced product hierarchy and better support of metric measurements would make it a lot better.

For example when I'm buying a sheet of steel, this list ordering isn't as easy to work with as it could be: 3/32", 0.095", 0.1", 1/8", 0.134"..., 1 mm, 2 mm, 3 mm...

Not really though because Misumi only sell to companies. McMaster Carr sell to anyone.

I think that's backward. Misumi let me create an account and buy whatever I want as a private individual, even in Canada. McMaster refused to ship to anyone here except for "trusted institutions" like verified companies and universities.

Not in the UK. I need to provide a VAT number.

Yes, the quality of the prints stood out for me and I also wanted to know on which printer this was done.

The author made a casing for a Prusa MK3/MK3S. So I assume this was used.

Based on his instagram stories, he's been using a couple of Prusa i3 MK3/S printers.