10-26-2016, 10:29 PM
I'm not 100% certain how the shop notes sled is designed, but if it is like the FWW sled it needs to really have the portion making contact to the planer bed be flat/square to begin with because you are shimming the board on the sled. Shimmed at both sides will end up being not far from just sending the board through without a sled. The planer is going to push the board down, and the knives will just mimic the shape they are pressed against. IOW send through a warped board, you will just get a thinner warped board, usually with exaggerated details. the sled allows for the flat bearing surface a planer needs, and you just shim out the board on the carrier, so it appears to have a flat bottom. Once you get one side done, you can flip the board and run it through on it's now flat bottom side.
FWW planer sled
FWW planer sled
Worst thing they can do is cook ya and eat ya 
GW
GW