I have found that the commercial rug shuttles with dowels start falling apart the minute you start using them, so I have built a variation which does not rely on a weak glue joint and can be retightened if it starts to loosen. If you don't have a table saw you can buy 2" wide stock and do the rest with hand tools. Not as sturdy as a glued center spline, but I made this in about 5 minutes in my warm basement when the machines in my shed were covered with frost. Tools were pull-saw, block plane, 2" coupling nuts with 1" X 1/4" flat-head machine screws, drill w/ Fuller countersink (drill press is better) to get screw heads flush.
