[sansbury]

Just out of curiosity, what is the reason to bore then ream as opposed to just one or the other?

[nitewatchman]

I bore first to be sure that I have a straight hole located in the right position. I you just ream a drilled hole, the reamer will likely follow the axis of the drilled hole which may or may not be straight or true. The reaming after boring is done to size the hole on the axis of the bored hole. The floating reamer holder is used to compensated for any runout in the system. This includes spindle bearing runout, spindle taper runout, toolholder runout and even the runout between the shank and the cutting end of the reamer.


If you ever get into chambering rifles, you will find that the difference in a good chamber (accurate rifle) and a poor chamber is a floating reamer holder.

gary