Different styles of headset. 1"1/8th will be threadless.
From what I can see the frame you have is old-ish, lugged and a skinny fork will suit it nicely. Also 1" forks will allow you to use quill stems which will probably also suit the frame better.
Unless you're hulk you probably won't need/notice the added strength/stiffness of an 1"1/8th steerer and stem.
Different styles of headset. 1"1/8th will be threadless.
From what I can see the frame you have is old-ish, lugged and a skinny fork will suit it nicely. Also 1" forks will allow you to use quill stems which will probably also suit the frame better.
Unless you're hulk you probably won't need/notice the added strength/stiffness of an 1"1/8th steerer and stem.