Ratrack,
No French in the spell checker, either.
. But seriously, glad to hear of your success with the tool. Not a surprise to me that it works well, considering the source.
Harry,
I first became concerned about floating reamer holders when I watched an acquaintance mess up a .308 chamber. He used a through-the-spindle setup with a spider to center the barrel on the outside back end. He indicated out the chucked end of the bore in a 4-jaw chuck. His tail stock was also indicated into perfect alignment, but where he blew it was that he then depended on a tailstock Jacobs type chuck to hold the reamer. Unless you buy an Albrecht chuck, you can usually count on several thousandths of an inch of mis-centering in standard chucks. So, of course, the pilot flexed the front of the reamer into alignment, but the back portion remained off-center and was only cutting on one of the reamer's edges. The back of the chamber came out way too fat. Cartridges ejected from it would not even fit into a .308 RCBS Precision Mic.
What Dave Manson described just starts with a foot of 5/8" cold rolled steel. You drill out an inch of one end 7/16ths for the reamer stems (I slightly under-drilled and used a half mil oversize 7/16" chucking reamer to get a close fit). Then you cross-drill the hole for tapping for 10-32 thumb screws to tighten to the flats on the stem. You turn the other end, if necessary, to fit your tailstock chuck. Just ahead of where the holder will emerge from the chuck, you turn one inch of it down to 1/4". Right in the middle of the rod, you also turn one inch of the length down to 1/4".
That's it. The 1/4" lengths are flexible enough so the rod will articulate several thousandth rather than allow the reamer to fail to follow the bore axis evenly. The drawback over the stubbier commercial floating holder designs is that it uses up almost an extra foot of lathe bed.
Nick