Whether to Edge Before or After Kiln-Drying

Most lumber producers edge before kiln-drying, but there could be reasons to do it first ó or not at all. October 26, 2011

Question
What's the best way to edge? After milling and to the kiln, or first kiln and then edge?

Forum Responses
(Sawing and Drying Forum)
From Gene Wengert, forum technical advisor:
99.9% edge first and then dry. The US Forest Service has for 30 years pushed a process called Saw-Dry-Rip (SDR) for softwood dimension but it never caught on. They have also done studies to show the benefit of edging hardwoods after drying, but it is not done.



From contributor A:
When I am selling the wood wholesale I edge by the grade rules to make the most money. When I am sawing for what I am going to dry and retail sale I edge very loosely, meaning I leave a lot of wane and really a lot of wane on Q-sawn lumber. Spalted wood I often do not edge at all as some prefer some natural edge stock especially the 8/4 and thicker stock. The wider the board the more it is worth. Also on lumber that I machine into T&G products you can often take a board that might S4S into a 1x4 but may T&G into a 1x6 product. I also produce some dried 1x2's when I edge after the kiln that work for cabinet wood.


From contributor U:
Natural edge flitch cuts on the specialty market is one thing for sure, but I do not think the US Forest Service would write a book about that. What advantages do they see Gene? I would think that it gives you the opportunity to edge around checks that happened during drying, but because sapwood shrinks more than heartwood, I would think you would be causing defects that would not happen if edging was done first. I would imagine the wasted space in the kiln would be such a disadvantage that any other advantages afterwards would be ruled out, and that's the reason why this technique never caught on.


From contributor E:
The edger can either make you a lot of money by upgrading your boards or cost you plenty of money in wasted wood and lowered grade, depending on the operator's experience and what market you are shooting for. While the wholesale market going by NHLA rules will permit sapwood and wane, your hobbyist retail buyers don't want that at all so you have to keep that in mind when you are edging your lumber.


From the original questioner:
Well I'm in progress of shipping hardwood lumber in bundles, random width and length for furniture use. Itís true that NHLA rules accept certain defects for certain grades, but we are in a world where competition is tremendous and a lot of wholesalers (in Europe) know it. A FAS board has to be with no defects like bows, wrap, and sometimes even with no knots, (certain wholesalers) even though it will be graded as FAS under NHLA rules. Thatís why I asked edging before or after because of the bow and other defects after a kiln.