Dahon folding bike steerer bushing replacement
The original was worn enough to allow quite a lot of play in this joint, which both supports the steerer tube and acts as its upper pivot point.
This replacement fits very snugly and, as intended, eliminates much of the slop. I will file the inside just a bit, actually, to make it easier to insert and remove the retaining pin, which is difficult to do without tools now.
To ensure longevity of high-pressure parts like this, and to facilitate filing, I suggest using the highest density fill (or solid, if possible) - this part is actually double-walled, which I suspect constrains how much further it can be filed down.