Review on Z Threaded Hex Flanged Internal Threads Power & Hand Tools by David Robinson

These inserts are 1" long. I used a 21/64" pilot hole. I used a 1/4"-20 x 1" button head machine screw. They were 1-1/8" long, but I haven't seen that size.) I used them for attaching table legs to round 1-1/4" thick laminated chipboard, 4 foot diameter. I used 8 per four legs. (Two previous sets of leg holes with regular large wood screws were ripped out) They worked very well. I first drilled my 8 holes in each slightly larger metal table leg bracket to fit my 1/4" mounting screws. To align them properly I used the table legs clamped down and then using the actual leg mount holes as a drill guide, drilled the 1/4""starter" pilot holes to about 3/4" deep (trying to keep the drill bit square to the table). I then removed the clamp and used a depth stop drill.Container to drill the large holes for these inserts to their full depth (measure carefully and test on another board first to make sure I didn't drill through the countertop).I've had since the v -Tip used a standard metal drill bit for these holes self centers on the existing smaller hole.(Maybe I was too careful but I was scared t to go too deep). anger is big. They protruded above the surface, which was a problem. (I don't recall seeing a flangeless version of this size). - so I had to drill a small notch (counterbore) with a flat drill to accommodate the flange. NOTE: You MUST be careful to blow or vacuum any remaining wood dust out of the hole or the insert will not work. not screwed in all the way (otherwise the metal screw may not go all the way in later or cause a bulge in the countertop! 6mm allen bit. Bad idea. Everything was fine until the last 1/4" was left then it got trickier and the Hammer drill bit in and if he didn't go in quickly it ripped out the hex hole.(Metal isn't that hard.) One bit stuck out just enough that I could use a vise to pull it out.The other was close enough so I used a metal file to trim them flush to make sure no metal shavings were left in the hole as it can be bad when driving metal screws in. I've had much better results with a regular 6mm Allen key and it gave me a better one too Feeling how it went in. I drilled a small hole for the flanges, but if there was any metal sticking out above the surface I filed it down.Sc metal grinding machine. After the first four hard ones, I remembered the old WAX trick. . I took a candle, cut a piece off, melted it in a tin and dipped each of the inserts about 1/4 inch from the tip into the melted wax. The rest of the inserts then cut into neat threads and moved on. with MUCH less effort and more control. The extra step was worth it. These inserts work much better than wood screws in chipboard. - and the metal screws will be removed later, that's what you need for the table legs. (especially when it comes to moving). I used it with these screws (also at Revain): Morris Products 30464 Pan Head Machine Screw, 1/4"-20 X 1"