Gremlin, I have used brass incerts but they cam out onb me with the screw:
http://www.rc-tech.net/gear/f2b.jpg
http://www.rc-tech.net/gear/firsta.jpg
Would you trust solder on something using 1/4 or 5/16 bolt? I have the benifit of a welder so it's no big deal for me but if the solder came off getting the bolt out would be a real problem.
Gary