My question is why did it bow? ...
I would like to know why it happened so I can design one that will allow for whatever caused that.
It happened due to moisture loss during the heating season. One just has to do one of two things: Either install some sort of system to add moisture to the shop, or plan on routinely flattening the bench top once per year.
It became critical this year, not because I started using hand tools, but because I just started using a vacuum press and I need a perfectly flat surface to be able to press flat veneered panels.
My bench top is the same as ever. 1" plywood sub straight, 3/4" high density chip board & 1/4" tempered Masonite replaceable top wrapped in Poplar & it seems to stay fairly flat.
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...I hope you can get this problem figured out.
You have a system that is pretty much impervious to relative humidity changes, Bart! I think I have it worked out, but I must monitor to determine how large the swings are. Then I will be able to decide on a system to install.
Not at all un-usual, bench tops are intended to be dressed now and then. I'd expect that over the course of several years of bowing back and fourth and re-flattening, the bow will become less pronounced each time. Get out a jointer plane (or pick one up if you don't already own one) and spend a morning re-flattening it.
I have started sharpening the large #8, John. I will wait until late April to early May, as the heating season will have ended by then and the top should be a little more stable. I don't want to start too soon, and then have a low spot
. I have also noted it, and added to the yearly machine maintenance schedule.
...Thus one of the best investments I've made has been my Wagner pinless moisture meter... one of those tools that after you get it and start using (relying on) it you wonder how you got along without it.
As for flat workbench... I assemble drawers etc on a 500 lb monster I built that is topped with 1 inch thick steel plate, covered with some hardboard. So it's always dead flat. Found the large steel plates under a RR bridge in a river, they were apparently spacers used in building the bridge. I managed to lug two of them home (200lb a pop) and built a table under two of them side by side. The table is thus so heavy it can't be easily moved, so I put some heavy duty wheels on it that came from one of those big metal trash containers.
Dave,
My Wagner unit is now about 12 years old, and a great tool! Highly recommended. That is indeed a monster assembly table - I would love to see some photos, if possible.
Thank you all for your feedback!
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