Threaded inserts

Gage the bottom end of the insert with a bit gauge. The bottom end is the one that has slots in it like for a straight screwdriver. They are NOT for that purpose! They are actually the cutting edges designed to size the hole to the correct diameter for the threads that follow. Use the bit that matches what the bit gauge says, (or a wee bit slightly smaller but never larger). Most retail packaging actually gives the bore size right on the package somewhere.

For driving you need a bolt and nut that matches the insert's internal thread. Run the nut up the bolt about the same distance as the insert is long. Now thread the insert onto the bolt up to the nut. Now you can use the bolt to drive the insert home. If you are concerned about the nut marring your wood surface just put a flat washer between the nut and insert w/ a nylon frictionless washer under that washer. The insert will auto flush w/ the washer arrangement but will not rotate on the surface of the wood. Once the insert is seated just loosen the locknut and reverse the bolt out of the insert and you're done.

Notes/tips:
After you drill the hole, use a chamfering bit to slightly ease the edge. This allows the insert to start easier..
paraffin wax the insert before inserting.
Prethread w/ a lag bolt that has the tip ground flat to cut threads for the insert for really dense wood...
For normal situations prethreading is not necessary..
Hole diameters for hard and soft woods are usually different. Soft being the smaller pilot hole
Insert thread designs are often different for hard or soft woods. End and face grain, likewise.
Remember, you can always make a hole larger.
Adding adhesive is a good idea. It makes the threads cut into the wood stronger.
Buy a few extras and practice on some scrap.

Knowledge Base & Engineering Resources

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For installation in "soft" woods, the manufacturer's recommendation - per the spec sheet that Stick posted - is to install the insert with the slot UP as this rolls the threads (by displacing the wood) resulting in a stronger joint. I used the available tool to install the inserts in my adjustable workbench, made from regular 2x4's, and the installation was amazingly easy. I've installed these inserts in red oak, and they have to be done as Stick describes.

More Threaded Insert Information

Sawdust74 said:

Anyone have a drill size guide for brass threaded inserts?

Click to expand...

Over 25 years ago, I was able to purchase threaded inserts that could be driven by a hex key. This was a nice feature in case you wanted to remove them. I don't seem to be able to find that style any more. Does anyone know where to purchase them.