I do hundreds of those brass knife type threaded inserts. I adapted a concept I found online years ago and made a jig for my needs. It works really great. I countersink the hole slightly to avoid raising the wood at the start. I fought installing these inserts straight and square for years. The shouldered allen drive bit is driven with a cordless drill with a clutch. Once the head of the hardened shouldered bolt hits the top of the jig the clutch is engaged. There is a steel sleeve to protect the hole in the wood. I leave space below the installed insert by drilling the hole deeper than is required. If the insert bottoms out sometimes it just rips the wood threads. Since I wrestled installing the inserts quickly and accurately for years I thought maybe this might be useful. The wood is 8/4. I suppose the wider the better depending on your needs.

Cheers,
Gordoninserts.JPG