I built an adjustable fixture that allows me to make very accurate loose
mortise and tenon joints. I have been using tenons fabricated from hardwood,
either Oak or Poplar. Needless to say, it requires some work to achieve the
1/4 inch thickness required for a tight joint.
I am now considering using 1/4 inch tempered hardboard. It is stable, strong
and has a uniform thickness. Any have experience with this technique??

John