Kayak cup holder with extended arm for T-track

You'll need a 1-½" or longer ¼"-20 t-bolt and ¼" nut to complete this as pictured. The print profile has a built in pause to add the nut, which will be embedded in the knob. Most other nut knobs that utilize a ¼" nut should also work fine with this cup holder.  For reference, the ¼"-20 nuts that I use have a thickness of 5.44mm or 0.214" and an outer diameter of 10.97mm or 0.432" measuring on the flats. 

This cup holder works best with t-tracks that are fairly level, as there is no angle adjustment. The arm will swing around and extend in and out for better positioning. 

The inside bottom of the cup holder tapers to 76mm or 3", while the top opening is 84mm or 3.3". It's sized to accommodate most cups, but some of the largest ones won't work.