I use a 44mm Meranti dowel for making wheels of wooden toys. Cutting the dowel on my bandsaw is a bit scary because every now and then the dowel rolls on the bandsaw table (even in a v-groove jig). After damaging yet another bandsaw blade, I decided to make this jig for handsawing the wheels. Bit more effort and sweat involved, but gives you nice 90-degree cuts across the length of the dowel. The slot is just large enough for the dowel to lie nice and snug without rolling around.
The front of the jig uses a "bench hook" type lip, so it can be held against the side of a bench, or clamped in a vice. I clamp it in the Tripton Superjaws, and simply sit on the back end for extra stability