The base plate is 1" wide x 3" long and 1/8" thick 4130, the tube that I made a fish-mouth in with a .875" end-mill is 1" O.D .035" wall 4130 and the bushing is a piece of mild steel with an OD of .875", I.D. of .6875" and length of 1.125". Again I went with a large enough contact area for the lock washers to hold onto (.9375" wall thickness).