OK, so I've got my Greenhouse Roof Cane Supports attached so its easy to Square (Japanese) Lash a vertical cane in place.

Problem is I use Haxnicks Tomato Planters for tomatoes and cucumbers and whilst lashing one cane is easy, lashing three is a pain, especially if you need to move the planter later.

I tried various options to join the tops of the canes from rubber balls to specially manufactured bell shaped rubber castings, they all worked to a greater or lesser extent but tended towards a degree of failure when attached to one of my roof canes.

So, flushed with the success of printing bits and pieces to modify/repair stuff around the house, I came up with this...

The prototypes (one pictured) was printed with PLA and (so far) they appear to be standing up the the rigours of temperature and sunshine really well. If (when?) they finally give out I will probably reprint them in PETG.