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I'm considering making up some go-bar deck rods similar to the one's used by Harry Fleishman, the ones that are tubular and use a spring to exert downward pressure.

The only question I have is "How much pressure should the spring have?"

Obviously the one in a ball point is too light and the valve springs in the 350 are too heavy.

5 lbs? 10 lbs? More?

Thanks for any info.

That's the ticket.

I figured somehere in the 5 to 10 pound range would be adequate to keep parts secure, minimize deformity and prevent a starved joint.

I have access to a fairly wide assortment of springs for testing so next I'll be looking for the correct diameter, wire size, length, et cetera.

Thanks for the data.

One of the things I like about spring loaded go-bars is that you can easily get a lot more clamping force. Mine top out at about 30 lbs each. This is enough to leave an indent on braces, but if you shape after gluing, that's not an issue. McMaster Carr part #9657K129 is a good spring. (1/2" OD, 2 1/2" length, .062" wire diameter, zinc plated high carbon steel) http://www.mcmaster.com/#compression-springs/=hc82ng. Here's a shot of the go-bars in use:

You'll probably get more responses if you post this question on the guitar building forum.