Hi.
Wizer I agree with Paul, you can shoot things bigger than 10 mm.
But it's harder.
My guess about the 10 mm that DC recommends is that when you shoot something bigger , only a slight problem in the setting of the blade, or if the piece if not square or whatever can lead to some problems.
For example, with the hypothesis that evrything is perfectly square (you shooting board, the piece you shoot, the fence, the ramp for the plane, the plane square itslef, ....)
If your blade in the plane is moved only 0.5° from the vertical, here are the distance that might result on your piece if you check with a square on the end (for a given thickness):
10 mm -> 0.087 mm
20 mm -> 0.17 mm
30 mm -> 0.26 mm
40 mm -> 0.35 mm
As you can see if you try to make a picture frame with a shooting board using 40 mm of thickness only a 0.5° of misalignment of the blade leads to a 0.35 gap. Wich is visible by human eye. As if 10 mm was used only 0.08, which with glue and a good finish could be acceptable.
This is the reason why (to my view) that often people do adjust their their shooting board as in the excellent model shown by Paul.
Also you can use some thin shavings or pieces of paper to correct all this. This also is something often raised in the forum, or in other places.
Finally, before shooting the real piece, you also often set up the plane, shooting board, on a test piece. Only once this is done you can go aheahd on the piece you' ll be using in your furniture.
This sounds complicated, but is quite easy, and fast when you do it.
Hope it helps (and also that I remembered my maths corerctly ... hard on the mornings
)
Regards,
Graween.
