Tractor trailer parts dealers.

Certainly not cheap. But a very useful fastener.

If I really wanted to use Grade 8 type materials, I believe I would source the correct Gr8 Socket Head Flat Head Screws and fab the sleeve to the desire length. Wall thickness of the sleeve could be controlled for the desired strength.

4130 solid bar or thick wall tubing would be a good material. Can't imagine that the price per piece wouldn't be cheaper.

Not to mention MATING SCREWS

FILM AT 11 !! ..............

they have a lot of choices too

https://www.gardner-westcott.com/

Do be aware of any of the LBGT offerings, They've been know to break down prematurely

Here I was under the impression that in a shear type of mount, a grade 5 is better, as a grade 8 is too brittle. Grade 8s are more for clamping pressure than shear. I think most stock suspension bolts are grade 5, are they not?
Just stirring the pot. Were the old guys wrong in using a grade 5 in shear?l

What I was told too, grade 5 for drive studs on axels more elastic, grade 8 has less shear strength, brittle. A guy had one of those tubular front ends with tubular lcas, while turning backing up slowly a 3/4” grade 8 bolt sheared off, car dropped to ground. Seams like a few had done the same so company made a double shear fix

Should've added for protection after washer LMAO

HMM never heard the above But with most uhh _____ coming from ______ a grade 8 could be a grade 2. I've seen some scary stuff from over there