Im my experience: If there's one thing that makes sense to stock at your own little lab - to avoid waiting 1-3 days for getting that little thing that blocks that project you want to complete - it's a wide assortment of connectors. The rest can often be improvised in many ways using various microcontroller boards and voltage level converters etc that you'll probabably already have.

The next most useful thing: A great assortment of fasteners!

I think the thing to do here is to buy like M2x60 through M10x60 (A4 stainless, insex screws) and then use that nut-retapping trick to get that custom screw length that you need.

"Do you mean cutting the screw to length with a nut on it, which then fixes the thread as you unfasten it?"

Yes. Looks like I've been too chatty for today, HN's rate limiting brutally tells me to shut the fuck up.

(The especially evil thing about this: You don't know until you press submit if your comment will be accepted or not. You could be writing the greatest comment of the week, but you have no idea if it will be automatically refused or not. You can only write and hope for the best. Fuck everything about that.)