I need a 1meter length of carbon rod of 14-16mm od, with a paired tube slightly smaller which can slide inside the id of the larger rod to form a snug fit as part of a wing joiner for a model plane.

I have done what you are looking to do, but with the smaller sizes of pulltruded CF tubes from EC.

I found that I had to very lightly sand one of the sizes of "inner-tube" to get it to slide freely inside the outer tube, the other size matched perfectly.

I used 6, 8 and 10 mm pulltruded tubes.

I have not tried the woven finish tubes, but I did get a 25 mm woven-finish tube, and it is very accurately 23 mm inside diameter, so I guess you will be able to use a combination of the two

For my project, I laminated a CF fabric braided sleeve ( EC have these woven sleeves in several sizes )around the outer pulltruded tube to reinforce it radially, as the pulltruded tubes have very little strength radially.

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