The thicknesser was made a while back from an old power plane. One fault was the adjustable plate was hinged at the back and didn't come up parallel to the sole of the plane. I've improved this by hinging both ends so it moves parallelogram fashion, being pushed up by an adjusting screw under the front edge.
The other problem was the taper sled which was wooden and not very stiff or flat. I bought some aluminium U channel and made a better sled, it is still somewhat flexible over a 3' length... but then, so is almost anything unless you go to box section steel.
I gave it a quick try out on a strip of Ash, I set it to quite steep taper and a deep cut. It did the job but with some chattering.
I learned a few things.
1. Stick the whole lamination down with double sided tape.
2. Only take a fine cut, and/or maybe gradually increase the taper.
3. don't try to pull it back out with the plane running. It will take other cuts and spoil the work
I'll have another try on a bit of scrap and report further.
Some of these taper/thickness machines that people make use a drum with sandpaper on, I reckon they must take an age to run through if you are taking off any amount of material, though they doubtless give a better finish. I imagine using this for rough taper, then running the lamination over the belt sander.
We'll see how much wood I ruin before resorting to working staves ;-)
Update:- I've given it a go with finer cuts and it works well, there are still some improvements to make as the parallel motion doesn't work at low angles and there isn't enough height for thicker billets. The wooden adjustable plate wasn't flat, but a few strokes of the plane have improved that.
I'll work at the design to try and make it good and rugged and versatile. It looks promising.