Local hardware stores. 3/4" round or square hardwood dowels. There has never been a rule they had to be aluminum or other metal. They only need to be long enough, strong enough, with a hole through the middle, to do the job. Hardwood meets or exceeds all the requirements.

Another plus is they can be any length you wan without shimming with a stack of washers or spacers. You only need to cut them to length. For $3.00 and 30 minutes of work you have everything you need.