I need to make a few arbors that hold the horizontal cutters, one 1 1/4 and a few smaller ones. I am going to make them like the few I have that are all one piece, where the keyed arbor is an extension of the collet section. the few I have seem to be 1018 going by the finish on the material. I am wondering what some of you guys have used to make these collets / arbors. I am thinking either 1144 or 12l15. I am guessing that going with anything harder like 4140 for example might not be the best material to be shoving up into the spindle, am I correct in this thought process or wrong? Thanks Todd