I made these from scratch, even the jam nuts. The threaded part started as 5/8" round bar 308 stainless, real LH/RH thread so they adjust without removing anything (1/4-20 thread, but double-ended, so one full turn is .100" and one flat is .016" or something). The ends are Delrin, whittled out of 1/2" sheet.
Attachment 155102
I finished them, then put them in the pile of 'neat stuff I made to put on the truck whenever I get around to it'.
That was in 2018. I finally stuck them on today, and only now only because the rubber on one of the original links rotted and it fell off and the right rear corner was no longer in sync with the rest of the world and I need to go to the grocery store in the next day or two hopefully before I completely run out of food.
Attachment 155103
So when you get down on yourself about procrastinating, or someone else does, remember this post and know that however bad you are at getting things done it could be so much worse.