I've made a couple of dowel jigs to use on a table and bench project that I'm making from 2 x 12 Southern Yellow Pine. One is useful for joining two pieces of 2 by # lumber and the other is for 4 x 4 lumber. They're very inexpensive as they are made from a scrap piece of 1" oak and some "steel spacers" from Lowes. Both have proven to be accurate and easy to use.

Plans for the first jig are available for FREE here: https://www.dropbox.com/scl/fi/eujfq3...
(Note: This link was updated 7/30/2023)

See Dowel Jig 3 here:    • Easy DIY Dowel Jig for Tabletops & Pa...