Cracks in a Butcher Block
Woodworkers consider why cracks would open in a butcher-block cutting board during orbital sanding. January 8, 2010
I made a bunch of end grain butcher block cutting boards for Christmas presents this year. All were about 2" thick, 14" x 16". I was sanding the last one (random orbit, 120g) and most of the interior squares started cracking. Not to the point of falling apart - it was still sound - but aesthetically appalling. I have built big countertops (7' long) in the same manner in the past and never had this issue. Any ideas as to why this happened?
(Furniture Making Forum)
From contributor M:
I would guess the heat from sanding caused the wood to crack - the wood was probably not quite dry enough.
From contributor C:
I have come across this before in my furniture restoration business. I think it is probably down to shrinkage. When butcher's blocks are used, they are cleaned down with water and possibly a detergent. This would swell the wooden blocks, causing them to stay tight in their frame. I am thinking if you applied an oil finish, it might just swell the wood enough to close up the joints.
From Professor Gene Wengert, Sawing and Drying Forum technical advisor:
A crack is evidence of wood shrinkage. Sometimes the cracks are in the end of the wood but not seen; they re-open as the wood dries (with sanding heat or dry air). So, do we know if these are pre-existing end checks or new end checks? If new, then the wood is too wet for the air.
From the original questioner:
Thanks for the input. Initially, I thought heat or moisture issues were to blame. The maple shorts that I used had been sitting in the shop for months and my random orbital, it would seem, couldn't generate enough heat to cause stability issues. But maybe, I'm thinking, it was a combo of the two that together was just enough to cause the problem. At least they were just cutting boards and not a huge countertop for a customer.