This instrument is built with a lot of work and mistakes, but then it works great. Didn't work well with hickory because hickory is so hard and brittle. Worked great on white and red oak and cherry. The setup tool they sent was useless. Watch the Joiners Guild of America video and cut installation time in half. Make sure the wood you use for the installation is exactly the same thickness as your final pieces. And the pieces are straight. Each curve in one piece with a gap in the corner.