Machine
The size of a drill press is twice the distance from the spindle to the column, so a 15 in press drills to the center of a 15 in circle. Old presses here run from Walker-Turner's 1930s 900 series and Craftsman's floor models to Powermatic's 600 lb Model 1200. Check how the chuck mounts, because a Morse taper spindle takes standard tooling and a tapered nose needs a matching chuck. Then ask the seller to spin a straight rod in the chuck, feed the quill down and let it return, and crank the table up the column.
4 models we cover.
Delta
Drill pressWhat to check before you buy →

Powermatic
Drill press$1,225–$2,325 typical ask
14 on eBay

Craftsman
Drill press$600–$600 typical ask
130 on eBay

Walker-Turner
Drill press$1,025–$1,050 typical ask
27 on eBay