My light-bar mounting notes list a split lock washer and flat washer with each quarter-twenty rack-side connection. The washers were part of the hardware stack joining the new extrusion to the roof rack.
The bolt and washer attachments at my extrusion connecting brackets.
Why I bought it
The added light-bar beam connected to the existing rack through three short drilled mounts. I assembled the rack side with quarter-twenty bolts, lock washers and flat washers.
Hillman quarter-inch split lock washers were included in the hardware list. The smaller 2020 extrusion used M5 bolts on the other side of each mount.
How I used it in my camper van
I cut and drilled the connecting pieces, then joined the two extrusion profiles with the appropriate hardware for each side. The quarter-inch rack connection included both washer types.
I also applied threadlocker to the bolts during that assembly. Positioning the rack T-nuts and the small 2020 nuts took additional time before the connections could be tightened.
The light bar above the rack after fitting its support assembly.
My review
The washers were small components within a joint that depended on several separate parts. My notes record the bolt, lock washer, flat washer and slot nut rather than treating the connection as a single piece.
The build photos show the completed hardware at the drilled connectors. The assembly sequence mattered because I sometimes had to reopen the rack connection to insert another T-nut.
A small connector joined two hardware systems, with a separate washer stack on the rack side.
Alternative products
Two alternatives to compare
Cionyce and IMScrews both offer quarter-inch stainless split washers. The Hillman item in my list uses zinc-plated steel, so the material and finish differ. All three use a split-ring form; the comparison here is the physical hardware supplied for a joint.
Cionyce Quarter-Inch Split Washers
These stainless-steel washers use a split-ring shape with offset ends. Their quarter-inch size provides a washer format for threaded hardware assemblies.
