go-bar tool construction

[peter havriluk]

I'm in the middle of making a go-bar deck.

So far, I've made two radius dishes from two layers each of 3/4" MDF board 2 feet square, glued together.

I'm using one layer of 3/4" MDF for both upper and lower panels of the go-bar deck itself.

I have four 2' lengths of 1/4-20 threaded rod to stand the upper and lower panels apart from each other.

So, I will have an air gap between the upper and lower go-bar panels of 22.5".

Any suggestions as to how long I want my 1/4" diameter fiberglass driveway stake rods to be? If I cut the rods to 24" long, each, then the rod will have to bow to allow a 24-inch rod to fit into a 22.5-inch space, less the thickness of the dish and the height of whatever it is I'm trying to clamp together. I suspect that 24 inches long is much too long, but I have no idea as to what would be a good starting length for the fiberglass rods.

Thanks very much.

[Hans Mattes]

I recently finished building a go-bar deck and it works fine. Here's what I did -- noting that, as in the rest of guitar-making, there are countless ways of achieving similar results:

I bought two sets of wire-running fiberglass rods from Harbor Freight (10 rods per package, each 1 meter long) and cut them in two, yielding 40 go-bars each ~19 ½" long. I covered the cut ends with vinyl caps intended for #10 screws (a package from eBay was ~$5). Then I used a kitchen scale to measure the force generated by the bent rods. Bending them from 19 ½" to 18" gave 5 ½ lbs. of force; going to 14" increased the force to 6 ¼ lbs. I set up my go-bar deck for 19" between the plates and found that worked well when gluing on braces to a top or back using a single radius dish. I used ½" threaded rod for my deck with wing nuts to position the top and bottom as different uses of the deck require different spacing -- I use the deck to attach braces and also to glue the top to the sides and to close the box. I attached a piece of Masonite pegboard (with the larger - ¼"? - holes) to the underside of the top plate of the deck so that the upper end of the go-bars won't move. In the past I've used a piece of scrap carpeting - that also worked well.

It's notable that the go-bars are definitely NOT linear springs, so the spacing isn't critical. Nonetheless, a reconfigurable go-bar deck is handy.

[peter havriluk]

Hans, what a wonderfully clear and detailed description of what you did. I'll take it into account as I set up my tool. Thank you very much for taking the time to describe what you did and why you did it.

[Kevin in California]

Hans I like that idea of using the pegboard material on the underside of the top of the gobar deck. I don't have a major issue, but every once in a while Robbies friend visits and causes a rod to slip. I will give that idea a try.

Pete, I have two sets of rods. One set is a length that works for gluing up braces, and another set for gluing on tops and backs. I have never tested the pressure the rods exert, that was done by feel and trial and error which you can do pretty easily.

I've been using it for 10 years and still works for me.

Kevin

[peter havriluk]

Kevin, time to give myself a dope slap. Two sets of rods will certainly go a long way to doing two jobs of immensely different heights...That's just too simple and easy to work! Now I gotta go find a second set of rods and it ain't winter. Maybe the merchant I bought the first set from has some left over from last winter or this winter's inventory showed up early. Meanwhile, I can make up a set of rods to do bracing.

Thanks, everybody!