hey buddy,glad to see a fellow machinist up here.the chassis starts out 1" thick.i remove the skin of the material first before machining to remove the stress in the material.by the time i dig it out from under the big pile of chips,out comes a chassis that is flat within .002.if the holes get stript out,customers can always send em back for repair.thank god for helicoils.
thanks for the nice comments buddy.