"J. Clarke" wrote in message
...
Reading your faq leads me to a question. First thing I cut using my
Incra jig many years ago was a box joint. Used a Freud straight bit
and the joint ended up not just loose but sloppy loose. I diddled
everything I could think of to get it tight and finally decided that
the bit was oversized. Went down to Coastal and they were out of
straight bits that size but had an Amana spiral. Tried that and the
cut was dead on. I've been using them for box joints ever since (and
since they're paid for quite a lot else).

One of the reasons for using a box-joint jig like
http://us.oak-park.com/catalogue.html?list=boxj-- see the demo. Adjusts to
fit the bit in question, as does the Leigh dovetail jig.