A new bit of hardware needs to be bolted down to the benchtop during use but I’d like to be able to stow it away the rest of the time. The base of the item in question features four M8-diameter holes, so I hunted around for stainless steel threaded inserts. I could only find stainless inserts in M6 (and got some for hypothetical future use), so I bought the only ones that I could find: 20mm-long yellow-zinc-coated steel inserts.
The plan was to mark the hole locations, drill, clear out the interiors of the holes, mix up half a thimbleful of the most suitable-seeming epoxy I had on hand (J-B Weld 8276 KwikWeld), smear it around the walls of the holes with a toothpick, and drive the inserts in. Mostly, that’s how it went.
I’m not adept at matching the correct size of drill bit to fasteners, so I wound up having to stop and replace the bit I was using with something girthier. The other hiccup was discovering that the inner-hex socket feature on the inserts wasn’t really deep enough for practical use, so I had to thread a short M8 screw into each insert and drive the insert down by turning the screws. Once the epoxy had set up a bit, it was easy to back the screws out of the inserts.
My drilling technique also needs further honing. I managed to tear up the surface of the wood a bit around the hole mouths. The lips of the countersunk insert heads hide quite a bit of that, but the tongue of gray epoxy visible in the photo above is filling in a small splintered-out region that projected beyond the top of the insert.