Thanks, I will look into this. I am assuming you get a hardwood dowel of the same diameter as the inside diameter if your smallest (lowest) section. thanks again and any more tips would be appreciated. MuleMule - your experience is why I have stuck to hiking poles as spreader bars. Hiking poles as spreader bars are about the lightest and strongest spreader bars you will find.
Lightest because you are already carrying them and the only added weight to the hiking pole is wood dowels inserted inside. (I assume that you are already using hiking poles. If not, they are still light since they are not carried on your back.
Strongest - here I don't mean strong because of the materials, although that is true also. But strongest simply because of the manner is which they are used.
Here is a schematic of my head end hiking pole used as a spreader bar:
You can see that for use as a spreader bar, there are a minimum of 2 nested AL tubes for the entire length. Added to that, there are wood dowels. The wood dowels are there mainly to keep the poles from sliding and shortening, but the dowels add to the bending strength also.
The minimum overlap of 4 5/8" is for the two strongest and largest diameter sections. The middle section and smallest diameter section have the greatest overlap of 16.5". The overlap of the pole sections give the poles used as spreader bars considerable strength and bending resistance. This is my head end hiking pole spreader bar. The overlap on my foot end spreader bar is even more since it is shorter as a spreader bar. My head end spreader bar is extended a total of 39".
This is in stark contrast to the use of the tent poles where the poles are butted together with no overlap of the pole sections them selves, only the pole-to-pole fittings. Those pole-to-pole fittings are the weak bending points as you discovered.
Also, consider that the tent poles are designed to bend. Some more than others. Tent poles are designed to bend with the wind forces rather than snap. Hiking poles are designed not to bend.
I had the tremendous strength of the hiking poles used as spreader bars very graphically illustrated to me when I had the head end spreader hiking pole slip while I was in the hammock and shear off the carbide tip of the pole. The pole itself was not damaged in any way. I merely replaced the carbide tip and you couldn't tell anything had happened. That speaks volumes to me about the strength of the hiking poles used as spreader bars. I no longer have any qualms whatsoever about using my hiking poles as spreader bars.