Recently, I purchased a bench top drill press from an individual. They were very generous and gave me various bits, sanding drums, etc.. Along with these items was a homemade woodworking jig that I have yet to identify a purpose. It's adjustable and looks like it might hold something round like a dowel, but the hold down clamps are puzzling...

Could anyone with woodworking knowledge suggest what this jig was made to do? I am including a photograph and would be glad to submit others if another perspective is needed.

TIA,
Mark