Lag bolts of 3/8” are a common size fastener used in the construction of log furniture and log railing.The under size 5/16” diameter pilot hole produced allows the threads of the 3/8” lag bolt to self thread into the log stock, making for a secure fit. Use of the 5/16” pilot point drill bit provided with the Tenonator™ produces pilot holes in 15 seconds or less, as seen in our video.