I am seeking some advice I have carefully watched your Basic Box Making DVD. My query is with the thicknesser. You don’t seem to get a tail in or tail out leaving that scoop at both ends of your timber. I have watched it over & over gone out to the workshop and tried again. Could you advise me of what I am doing wrong? It is driving me insane. I also hope it is alright to contact you for advice.I think what you are describing is "snipe" where the cutterhead on the planer dips into the stock a bit as the wood is released by the infeed roller of the planer. Snipe generally leaves a deeper cut across the width of the board, 3 or 4 inches from the end that can be difficult to sand out. There are some planers that are better at controlling snipe than others. The height of the table rollers can make a difference and for planing thin stock, putting a sheet of plywood or melamine over the surface of the table can help by bypassing them. The in-table rollers are intended to ease the planing of rough stock, but are unnecessary for preparing stock for box making.
The infeed and outfeed rollers exert a great deal of force holding the stock down firmly to the table, and sometimes the stock springs up slightly when the pressure is released, allowing the stock to lift slightly into the cutterhead. I generally lift up on the stock as it exits the planer. What this does is create some leverage on the stock, holding it more tightly to the table, counteracting the effect of the roller release and reducing the potential for snipe.
I don't know if any of this will help. I don't know what kind of planer you are using, or whether the stock is straight as it is being planed. There are lots of variables in surfacing materials, so without knowing a great deal more, I can only speculate. But the easiest thing to do first is to hold the stock up on the outfeed end during planing and see what happens.
Woodworking tools function on the basis of Newtonian Physics, even though at times they may seem to have a bit of Heisenberg uncertainty thrown in to boot. The key is understanding the way things work and knowing that any problem unrelated to the space-time continuum can be solved with a little study and by holding your mouth just right.