Clem, to my mind the simplest way to make the groove is to use a straight cutter of the correct size, probably 1/8" on the router table using a tall fence which is a very useful addition to every-ones workshop but don't attempt it in one pass, two or even three with such a small dia. bit. In the photo the material is 1 3/8" with a 5/32" groove. An 1/8" cutter is much cheaper than a slot cutter. Normally in a correct size groove there is no need for glue or pins.
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