Progressive 2600LPXST Polished Brass US3 2-1/4" Pinned Door Knob Set With Spindle For Lockwood Surface Mount Mortise Lockset & More. brass pinned to a straight spindle knob set for Threaded 3/8-18 for Lockwood mortise locks. Standard duty 2-1/4" knob is factory pinned to swivel spindle for 1-3/4" door. Spindle has two 3/8" centers. Inside knob has two case hardened set screws and spindle is threaded 3/8-18. Packed one pair per box.