Attachment 415860
I set up my Sjobergs 1500 bench in the Cave of the Modern Neanderthal about a year ago (Sept 7, 2018). Picture above was from the first day after it was all carted up the stairs to the Cave and assembled. I was particularly pleased that the top was really flat. I was puzzled and bemused about the care and maintenance guide that came with the bench. It started out with a defensive paragraph and graphs about wood movement and fungal growth with moisture.
https://www.woodcraft.com/media/W1si...d3afc852b28a9f
I confess that I had not done my usual deep dive into internet analysis and review of this bench before purchasing it. After reading Sjobergs' disclaimer, I proceeded to search out and read many reports and of how bad beech was as a workbench wood (baloney), how several Sjobergs benches warped badly when stored over the winter in an unheated warehouse in coastal Canada (not surprising), and various other negatives. I believe the disclaimer was a response to the criticism. I began to have doubts about my purchase but by then the Elite 1500 was already in its new home and I would just have to flatten it if it warped or bowed.
The climate of the room in which the bench lives is completely relevant to the story. The Cave is not at all a moist, underground cave. It is a room on the top floor of a four floor building and it is actually the home of the two air handlers for the condo. The condo has two levels. The air handlers are "open plenum" , meaning that a huge return air duct pipes air into the Cave from the top of the two story foyer. The air handlers draw from the room. The room is, in effect, part of the return duct. When both units are running, quite a force is needed to pull the door closed. Also, since the duct is at the very top of the foyer, the Cave tends to be the warmest place in the condo. This description should convey the environment in which the bench exists. It is a a warm, conditioned, well-ventilated space in Atlanta, Georgia. I do not have a thermometer or hygrometer in the room, but tools in the room have not accumulated any rust so it must be about 50% RH in the summer. Probably quite a bit less in the winter. I would rate the Cave as good a place for a bench as you could reasonably expect to have in the Southeast United States.
I was disappointed but not surprised that I was able to detect hump in the middle of the bench after about 6 months. Wood does move. My measurement was a 2 foot ruler which I oriented cross ways (perpendicular to the grain) on the bench top. It rocked a bit. When I pressed down on one end, the other end would be a 3 or 4 mm off the top. It was not bad and the curvature was more at the edge than the middle. The breadboard ends were straight so the distortion was just a mound in the middle of the main slab. The bench manufacturer cannot anticipate where a bench will live. To me, flattening a bench top should be considered routine maintenance not a defect. I took to Google and looked at several videos of people tackling the flattening process. My thoughts were that I could easily make matters worse. Anyway, I did not have a lot of time in the shop to take on the job.
Well today after a summer at the lake, I am back in Atlanta and the bench is flat again. This is a lesson in the happy consequences of procrastination. I mean it is really, really flat. Here are the best pictures I could take to illustrate. The ruler applied lengthwise is 4'. I see no gaps. A 2' ruler placed laterally does not rock. It is hard to get a good photo of the edge. Trust me it is flat.
Lengthwise
StraightEdge1.jpg
Lateral
StraightEdge2.jpg
Congratulations to the bench for acclimating successfully. Thanks to the wood scientists at Sjobergs for successfully kiln drying the 4 inch wood with so little internal stress and for accommodating movement due to moisture acclimatization without creating more stress. I still like this bench quite a lot.