I always used "tight". Check the bolts that hold the WAF's on, because the wood will shrink over time. When I bought my first KR ( 90% complete and only took 6 more years to finish ), I found that the bolts were very loose and "snugged" them up. You want to be careful not to crush the wood.
There is a time for building and a time for FLYING and the time for building has expired. See N64KR at http://KR-Builder.org - Then click on the pics Daniel R. Heath - Columbia, SC See you in Mt. Vernon - 2005 - KR Gathering
