Large Timbers for Workbenches
Like most things workbench, the trends are set by Christopher Schwarz. So when he started using heavy timbers to build benches suddenly everyone started looking for 6×6 timbers and wide slabs for bench tops. Granted I work for a lumber company, but these timbers are not that difficult to find if you make a few phone calls (remember that thing with the curly cord?). There are some things you need to look for in particular that will make your bench building process a lot easier.
Free of Heart Center is a grade designation that means the timber is cut from off center leaving that nasty, unstable pith out of the board. This will save you a lot of heart ache when it comes to end checking and overall stability of the piece.
In most cases, these timbers are air dried and can be anywhere from 20% to greater than 40% moisture. Timbers like this are primarily used for exterior construction and kiln drying would cause more problems than not. This doesn’t mean you can’t use these wetter timbers but you can imagine what concessions will need to be made while working. If possible looking for kiln dried varieties that are used for interior post and beam construction. These are dried to 6-8% to 2 inches deep. What remains in the center is usually 12-15% and this doesn’t pose a problem. Usually these are marked as “select structural grade” but that doesn’t guarantee kiln dried. Just ask your supplier. If money is not an object then you can find radio frequency dried timbers that have a consistent 6-8% content all the way through.
Watch Your Lengths
Since these timbers are primarily used for home construction and exterior structures like pergola and such it is rare to find them in 8′ lengths. 12′ is more common but 14′ and 16-30′ is the norm. With most bench tops coming in around 8 feet long this is something to consider so that you don’t end up with a bunch of large waste. With a 12 footer, you should be able to get a top piece and a leg from it but 14′ pieces may yield a lot more unusable offcuts. Specify your lengths carefully.
All of the above may not be possible in your area and it doesn’t mean you can’t build a large timber workbench. Ask Christopher Schwarz. It wasn’t until he bought a large order of Douglas Fir from me that he was able to get kiln dried material. That hasn’t stopped him from building 5 or 6 workbenches a month for the last 6 years.