I am working on a hand railing that consists of steel posts with an 2x4 ipe top rail. On the top of each vertical post is a horizontal plate 3.5 in x 2.0 in x 0.17 in thick. The top rail is screwed to these plates. In order for these plates to be flush with the bottom of the wood; 0.17 in. of the wood will need to be removed so the plate can recess into the top rail.
I was provided a 1/4 in thick plywood template to do these recesses. The template is the same size as the needed recess. The corners are 1/2 in radius. The problem I am having is finding the right router bit to do this task. A top bearing flush trim bit seems like the right choice, but all of the ones I have found will make the recess far to deep. I only need to remove 0.17 inches wood.
To uses a collar and straight bit would the template need to oversized due to the clearance gap between the collar and bit?
-Clay