I tried the thread inserts once in maple blocks and maybe i did,nt use them right but they split the maple block. good thing i had the piece of maple epoxied solidly in the plane. many hours later i got the block out and cleaned up enough to put a new block in. i think it was the second post was right on the drill bit probably wobbled but figure a blind nut quarter inch has approx. 3/8" of threads so if you have at least that amount of good thread you should be in good shape. buy the way if you are running a 1/4 nylon bolt there is no way you will ever strip out a piece of maple that is one tough wood. used to use them as motor mounts back in the olden days.