Recently I was thinking about this again and how to put multiple wood post screw insulators on one post effectively.  My first thought was simple take a lot of boards and screw insulators into them, then use wire to tie them to the post.  But this would involve a lot of wood, which would mean an extra cost as well as eventual problems with rot and a good bit of wire needed as well just for attaching to the posts.  The next thought was to drill through the post and attach the insulators with metric screw thread, nuts, and washers.  Then after having used polyurethane glue for the first time making the tool storage drawers, how I would do it all came together.

On the insulators I have the screw thread is 5.8mm and the smooth shaft is 4.8mm, so I used the 5mm SDS bit to drill the hole into the post.  Be sure to blow, or perhaps even better, use a stream of water to clear the concrete dust out of the hole (wetting the hole helps the glue set faster).  Attaching a piece of tape to the drill bit can help to ensure that the hole is deep enough for the insulator without going all the way through the post, as this sometimes knocks off a chunk of concrete from the back of the post, probably weakening it.

Then fill the hole with the polyurethane glue, and within the open time of the glue, screw in the insulator.  As long as the drill bit went precisely, the thread of the screw will slightly deform and make a tight fit right away.  But even if the bit jumped around and made a slightly large hole, the glue will still hold the insulator in fairly well.

Tools needed:

• SDS hammer drill
• Appropriate drill bit
• PU glue with a suitably long open time and suited for outdoor use
• Tape
• Extension cords / generator, unless you have a cordless SDS drill