Go bar setup

[Jeremy D]

Hi guys.

I just finished my go bar deck and I was wondering if you could take a quick look at the rod deflection and tell me if it looks about right? They are tassie oak 9.5 mm rods, simply because they were cheaper than pine. They seem pretty stiff so I am thinking maybe I should take just a little more off them?

[DarwinStrings]

They look in the ball park compared to mine and I use the same Tassie Oak dowel (some dowels are stiffer than others too) but remember when you have the thickness of a back as well as a 20mm brace in there then you will bend them more. I made my deck height adjustable to cope with different jobs (I do all sorts of stuff in there, not just guitars). That would be easy enough with yours as you could just use pins through various holes in your uprights.

Jim

Edit. My top is much more rigid as well, yours will flex under load a bit.

[Jeremy D]

They look in the ball park compared to mine and I use the same Tassie Oak dowel (some dowels are stiffer than others too) but remember when you have the thickness of a back as well as a 20mm brace in there then you will bend them more. I made my deck height adjustable to cope with different jobs (I do all sorts of stuff in there, not just guitars). That would be easy enough with yours as you could just use pins through various holes in your uprights.

Jim

Edit. My top is much more rigid as well, yours will flex under load a bit.

Thanks for the reply Jim. Yes the top is one piece of 22mm ply. The bottom is 2 pieces. Hopefully this is enough. I left the threaded rod long at the top in case I need to make it adjustable or I need to add more rigidity to the top.

Thanks again.

[Crafty Fox]

Looks good. Where did you get the rubber tips from? Bunnings?

[Lillian]

I have to agree with Jim, you might need another layer up top.

The only possible issue I see with the rods might be the tips. If they have silicone in them, it might contaminate the wood. You can do a test on a piece of wood by leaving it clamped up over night and then putting a finish on. If you get fisheyes in the finish you'll need to find different caps. Otherwise, its good to go.

[kiwigeo]

Looks good. Where did you get the rubber tips from? Bunnings?

Nicked off his grand parents' walking sticks

[Jeremy D]

Looks good. Where did you get the rubber tips from? Bunnings?

Bunnings, are the 10mm ones and come in packs of 4 for 2 dollars.

I have to agree with Jim, you might need another layer up top.

The only possible issue I see with the rods might be the tips. If they have silicone in them, it might contaminate the wood. You can do a test on a piece of wood by leaving it clamped up over night and then putting a finish on. If you get fisheyes in the finish you'll need to find different caps. Otherwise, its good to go.

Thanks Lillian, I never considered that they might contain silicone. I might bang another layer up the top as I have some laying around.

[Kim]

They look just fine. As long as the bars are deflected that is all that really matters.

Despite common perception, there is no increase in applied clamping pressure from that point of deflection of a gobar until the sudden 'decrease' caused by its catastrophic failure.

This is to say that once a structural column begins to deflect under load it will continue to do so until it fails. This is because it has no mechanism by which to resist the load causing it's deflection. Therefore, the only reason a gobar does not continue deflecting until it breaks when clamping is because the load responcible for causing the deflection is arrested by the static nature of the upper, and lower decks.

Cheers

Kim

[charangohabsburg]

+1 on a sturdier deck top, or the first bars might drop out before you put in the last ones.

Mine looks like this:

[Kim]

BTW Taking more off of your gbars will only make them 'more' stiff.

Cheers

Kim

[Jeremy D]

They look just fine. As long as the bars are deflected that is all that really matters.

Despite common perception, there is no increase in applied clamping pressure from that point of deflection of a gobar until the sudden 'decrease' caused by its catastrophic failure.

This is to say that once a structural column begins to deflect under load it will continue to do so until it fails. This is because it has no mechanism by which to resist the load causing it's deflection. Therefore, the only reason a gobar does not continue deflecting until it breaks when clamping is because the load responcible for causing the deflection is arrested by the static nature of the upper, and lower decks.

Cheers

Kim

+1 on a sturdier deck top, or the first bars might drop out before you put in the last ones.

Mine looks like this:

BTW Taking more off of your gbars will only make them 'more' stiff.

Cheers

Kim

Cheers guys.

[jeffhigh]

http://en.wikipedia.org/wiki/Buckling
look about halfway down for "bifurcation buckling" which is what we are using in Go bars.
In the range we are using, increased deformation gives very little extra load.

I prefer slender bars in large numbers to give a more uniform clamping pressure and ease of use,
My deck does fine with 18mm ply top and bottom