Dovetailed Workbench Skirts and Humidity

[Jim Neeley]

I have seen workbenches where the bench skirts are dovetailed, such as the purpleheart one below and they're beautiful.

I have also read that when joining skirts with bolts that you should install them in a slot to permit the bolt to slide as the width of the bench changes with the seasons.

I'm aware of using splines to align the two but something needs to hold it all together.

188149

How was this done to allow for bench width changes due to seasonal humidity shifts?? I would seem that some amount of glue would be used in the joints.

[Mark Baldwin III]

Do I even want to know what a bench like that costs? yeesh!!

[Jim Neeley]

I dunno.. 'taint mine. Though I'm guessing they'd be pretty peeved if seasonal expansion and contraction split the top so I'm guessing there's a secret I don't yet know. <g>

[Brian Kent]

I made a bench with the body of the Frank Klausz design, and a different end vise. The wood on both ends is supposed to ride on a spline to account for wood movement, with a very large bolt in the center holding the end boards to the rest of the bench. On this photo of a Klausz Bench you can see the bolt behind the end vise. http://www.workbenchdesign.net/frankbench.html

When I made my bench I was just 5 months into woodworking, and I did not realize the ends were supposed to float. I glued the purpleheart ends to the maple table top boards. Fortunately, the stresses have never exceeded the glue bonds so it has held together nicely. If it ever breaks loose I will do it right and float a spline with a bolt in the center.

[Jim Neeley]

I'm wondering since I'm looking at a similar setup (twinscrew) and the I like the look of the dovetaills.

[Andrew Gibson]

On my bench I made a tenon on the top board that ride in a grove in the end caps. Basically the same idea as a spline. I used lumber that had been kiln dried then has also been air drying for an additional 6 or so years. it seems to have worked well. I will get back to you in a year or 2 when the seasons have cycled enough to make any flaws show up.

[Dave Anderson NH]

I guess that I'm confused. Do you mean a skirt, which I define as a vertically oriented board on one or more of the long sides of a bench, or do you mean an endcap? By my definition, a skirt would be no problem since it is long grain to long grain. If you mean an endcap, that is a whole different matter since you are setting up a cross grain situation. I suspect that Brian hasn't had any problem for 2 reasons, his shop doesn't change humidity and temperature levels that much so movement is minimal and second, if the top is laminated up out of boards vertically oriented, most of the movement is through the top thickness and not the width of the top. Personally, I feel that unless you are installing and end vise of the double screw type, I see no need for an endcap. An endcap only complicates construction and perhaps fancies up the bench a bit. YMMV.

[john brenton]

That funky workbench with the tusked tenon was featured in Shleinings book, and it's made entirely of purpleheart.

That Klausz bench is so awesome. I never noticed that the tail vise was joined with a mitered dovetail...I bet you can find something new on that bench every time you look at it.

There's a case to be made for forgoing the end caps on workbenches. It makes more sense just to seal the ends up real well with lots of BLO and a wax.

[Brian Kent]

Dave, I agree with my lucky escape due to small humidity changes. I would never recommend gluing the endcap like I did. It has never occurred to me that an endcap isn't even needed, though.

[Sean Nagle]

The only way you can safely dovetail endcaps onto a bench at all four corners is by incorporating a tool tray. That purpleheart bench top is violating prudent design practices to allow for wood movement.

[Tim Sproul]

1. They dovetailed both ends and were lucky to get a top that doesn't move enough to break.

2. More likely, they floated the endcap towards the back of the bench (dovetail only between endcap and front skirt). There, the end cap is probably attached with a bolt or two residing in enlongated counterbores. You can't see what they've done from that one picture.

[Jim Neeley]

Foregoing end panels makes a lot of sense to me as long as you're not planning a twin-screw end vise.

Tim, I think you're onto something here...

If the front and rear skirts were held on to the benchtop with glue or some other fastener and the ends were affixed in one (?center?) point with a bolt, the dovetails would not need any adhesive. Assuming the ends were sized around the bench at its minimum width and the dovetails were substantially longer than the bench expansion, they would serve solely as sliding joints as the top grew in width.

Does this seem sound to others?

[Rob Lee CT]

A vote for a split top design: if there's a large enough gap in the center of the bench (1" will do for a pair of 12-14" half tops) you can dovetail each end, pin or bolt the dovetailed end of the end cap to the bench top, and let the top expand to the middle.

[Jim Ritter]

I could be wrong but I think that bench has a tool tray down the middle. My bench has dovetails all around, wood movement dealt with at the tool tray joint.
Jim