In article , Wood Guy wrote:

A friend wants to build a fence using round, 6" diam cedar posts and 1"
x 6" pine or spruce boards.

He wants to cut slots through the center of the posts (3 slots) that are
just large enough to slide the boards through. There are going to be
lots of posts - maybe 100 or more.

How would you go about forming these slots? What sort of tool?

Well, you could get all tooled up with a hollow chisel mortiser, or all
burly with a mallet and a mortising chisel, but if you are more into
getting the job done fisrly fast and not buying fancy tools, a good
sized router with a carbide bit and a jig should get the job done,
albeit with rounded ends on the holes. Have to go in from both sides.

Pay attention to drainage or you'll have rotted boards in short order.

--
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