Re: Dowel Rod ----> Jo?
Yeah, I've made a few myself and a few bokken. Hell, I put together koshirae for swords so why would I want to pay someone else to do it for me with a jo or bokken? And fwiw, I do have some really nice ones bought from various folk out there doing this work themselves because I like to support those who do it. And if someone wants to perform that meditative act of cutting, sanding, and oiling then by all means go for it. Years ago I made a handful of shorter jo so I could start kids off with properly sized jo.
If you can find a white or red oak 1" diameter piece that's relatively straight, go for it. Clean it up, wipe it well, do what Phi suggested up above or go with something like a good minwax finishing wax (you'll need to reapply occasionally).
And to those who worry about stick to stick, there's some discussions out there about how various woods react. Use google and search for it. Kim Taylor has written some good stuff on the topic over the last decade.
And frankly the first thing I do if I get a new weapon from some other place is strip the finish and redo the whole thing. Because it's what I do. And because I enjoy it. And because it's fun. And because I can. And because it makes it more "mine". Hell, I usually reshape bokken I get just to make them a bit more to my liking...
All that said you can also find relatively inexpensive jo if you look on-line in places like karate supply places. They're generally cheap but they work (although with most of those I'd still stay away from any significant contact).