In article om,
wrote:



is it this device?:
http://www.leevalley.com/wood/page.aspx?c=2&p=32250&cat=1,180,42311,42319
Yes it is


if so, carefully examine your bushings to be sure that the holes are
bored concentric to the threads. mine are out, and I had to do carefull
shimming to get them in line, and now that they are it's a
one-dowell-size-only tool.

I will examine it but I do not think that is the problem. there is
just too much movement of the bar. If the bushing were off then the
error would be the same for every drilling. It is not. Sometimes I
can get it to line up pretty well. Sometimes it is off by a mile.