I am looking for the name of the part below. It is a metal connector that has a vertical threaded shaft into which a bolt can be screwed. The base has holes around the shaft that allows the part to be bolted onto a flat surface. This connector allows a bolt to stick up at precisely 90 degrees from the flat surface. I tried searching for this part on McMaster-Carr, Lowes, Home Depot, but cannot find the name.
Alternatively, some other fastener that secures a bolt exactly 90 degrees to a surface would also be useful to know about.
Any suggestions or pointers would be greatly appreciated. Thank you very much.