Lamp Post Component

This is a first pass at making a replacement part for a lamp post. The original part is metal (presumably aluminum since a magnet doesn't stick to it), and it broke. So I'm trying a plastic part with a thicker wall. We'll see if I can get it sized properly to be installed. after that it will be interesting to see how it holds up to the stresses and heat of the light.

The set of 3 holes are a pilot for M4 tapped holes, and the hole at the bottom is so mark where the center of the part is. A larger hole will need to be drilled in, but since the part is broken in that location I don't know how bid of a hole is required.