1/4 in. - 20 x 20 mm Zinc-Plated Steel Type-D Insert Nuts (4-Pack)

These inserts did not work well while threading into beech. Even if the pilot hole is drilled slightly larger than it really should be, these strip out very easily where the alan key fits. Be sure to have an easy out tool or similar if you are installing these in a hardwood. Also be aware if you are purchasing these in the store, there is an almost identical package on the shelves right next to these that has almost the exact same product, but flangeless. I didn't even notice I had picked up 2 packs of the flangeless ones, which were even worse.

Instructions on back say to use a 5mm hex wrench to install it - you need an 8mm hex (Allen) wrench to install. No problems with bolt threads. These are zinc die-cast inserts - pricey for what they are.

Great for quick installation of insert into wood. Used many times and found it a very good design.

Only one of the four insert nuts would accept a 1/4-20 connecting bolt using reasonable force. I had to run a 1/4-20 tap through three of them. (Luckily I had one!). They inserted without much difficulty into soft wood. After insertion, however, I had to again run a tap through two of the inserts in order to insert the bolts with reasonable force. I was using bolts that had to fully engage the inserts. Perhaps they would perform better if shorter bolts were used My application requires repeated assembly and disassembly of the joints implemented with these inserts. If I only needed a one-time joint I possibly could have forced the connecting bolts into position. Pros: low cost Cons: poor fit