i have a just cut 3 inch thick cross section from the trunk of a maple. how do i make a cutting board/chop block? i know it has to dry and be sanded, but what steps do i take to do this?
The cross-section of a tree trunk like you describe will be almost impossible to dry without damage. Because of the way trees' cellular structure works, wood tends to shrink, as it dries, something like a pie being eaten slice by slice, or like a paper fan being closed. The diameter will not change much, but cracks will open from the center out to the bark, and cracks in a cutting board are a bad idea. There are exceptional circumstances, but simply drying and flattening the slice is fairly unlikely to work.
To get a similar look, you may have to cut the slice in half while it's green, so that it can shrink without damage, then flatten the cut edges and glue the pieces together after drying.
The diameter will change (this is called radial shrinkage), but in most woods, the circumference will change about twice as much (tangential shrinkage). Since
circumference = pi * diameter,
something has to give and a split usually occurs. There will me negligible shrinkage along the grain, (up and down the tree), in your case, in thickness.
Otherwise, I agree with Jon1270
One trick I was told about, but have not tried myself, is to coat both surfaces with 1/4" or more of beeswax and set it aside for a year or so. This is supposed to slow down the drying/curing process and thus reduce the splitting that occurs when the wood dries unevenly.
This was done by wheelrights that needed unsplit logs for wheel hubs.
My saying: "In the end, the wood has the final say."
R.Bruce Hoadley put it more broadly:
"Wood comes from trees. This is the most important fact to remember in understanding the nature of wood. Whatever qualities or shortcomings wood possesses are traceable to the tree whence it came. Wood evolved as a functional tissue of plants rather than as a material designed to satisfy the needs of woodworkers. Thus, knowing wood as it grows in nature is basic to working successfully with it."
Wheelright's hubs have two advantages
1. They have a hole in the middle. Ponder the math of this.
2. They were made from a wood with interlocking grain and less prone to split.