Goberge or Go home

The Go-Bar deck is a clamping device that figures prominently in instrument building.  It’s origins are murky but the concept is found in both French and Japanese  woodworking going back a few hundred years, where they are referred to as a Goberge and a Shimbari respectively.  It’s a simple solution to getting direct downward pressure on a number of points over a wide area.  Clamping pressure is via bendable sticks that provide spring pressure from the top to the bottom of a box arrangement.   And of course you can buy one. 

But since I had some plywood lying around, a Menards close by, and a great French accent, it’s a simple project.  Two plywood squares, some assorted nuts, washers, and threaded rod and I have the box.   The spring clamps are another matter. 

In the olden days these were thin pieces of wood or bamboo, in modern times people use fiberglass rods.  I don’t get a good feeling from the fiberglass rod idea.  I’m imagining several issues and I haven’t even tried it.  The rods are a set length so you have limited ability to adjust clamping pressure, and in addition the bend in the rod is bothering me – the force vector is vertical but is there also a horizontal component?  High school physics students, please chime in.  Plus, I’m imagining that as these bent pieces are installed its going to be more difficult to navigate the space without bumping into some of them, knocking them loose or into other rods.  Don’t get me wrong, the fiberglass rods are very widely used so they must work,  but I have another idea.

The thing that comes to mind is a spring-loaded curtain rod – the inexpensive round ones that adjust by twisting the barrel.  I know I’m not the first person to think of this, and this is reinforced by an exploration of Bob Gleason’s site (Pegasus Guitars) and the discovery that he makes his own spring loaded rods out of PVC pipe and wood dowels.  Bob has been doing this for a long time so when I saw this I realized this idea had merit.

Off to Menards to check out their curtain rod selection!  The Kenney 18″-28″ Spring Tension Rod cheapie seems a likely candidate and when I get it home, works like a charm. 

One benefit of this version of the Go-bar rod is that the pressure is in a direct line, another is that you can adjust the length/force on the fly.  This is a huge plus when you’re putting clamps on a piece that varies in depth while the glue is quickly setting.   A third benefit is that you need fewer rods because these are adjustable.   So while I have nothing to compare it to, I like the way these work.

The Kenney 18"-28" in all it's linear, adjustable, spring-loaded glory

I liked it so much I got excited and posted about my genius contribution to Luthiery!  Alas, my enthusiasm was met with lukewarm reactions or crickets – Bob Gleason tried them and even he was unimpressed!   But this is part of the fun.  There are lots of ways to accomplish the various tasks associated with building a guitar, and sometimes fools rush in where angels fear to tread.

I will continue to blaze new trails, follow at your own risk!  And be sure your insurance is paid up.

Bob Gleason: great guy, amazing artisan, not a big fan of curtain rods