length of plastic plumbing pipe of diameter just greater than your steerer
keep it long enough to allow you to hold the fork against it upside down and bang the free end on the floor (better than standing the fork lowers on the floor while you bang down, I think)
If race is a very tight fit you might try (in order of preference IMO:
Heating the race in boiling water before fitting
bit of grease on the steerer
“ease” the inside of the race slightly and VERY carefully with a curved file
cut a slot in the race (unless it’s a very wide one such as an adaptor for standard steerer in a 1.5 headset) (actually I often do this, but some others dont like it so I’ve put it last)