I'm building a bike and when i was putting the front wheel i noticed that it won't fit in one of the dropouts of the fork even though i tried it before. The only thing that changed between those two attemps was that i installed the star nut (using the proper Topeak tool and a rubber hammer).
I solved the problem bending the dropout but i'm wondering what do you do to avoid the damage to the dropouts while hammering to install the star nut

Install the starfangled nut with a front wheel in the fork. (or axle with nuts, or plastic dummy axle)

Or with steerer clamped in a workstand so that fork dropouts are not contacting any surface.

Don't use a good wheel. You are effectively hammering your wheel bearings.

Use an old wheel or dummy axle is a good idea.


-Tim-

I set the fork on a piece of 2X4 so the dropouts don't touch the floor.

Me too, I made a padded wooden tool, a hardwood 2X4, I rounded over the top corners to fit into most fork legs. The padding is a thick piece of leather wrapped over and stapled/glued.

Only when the crown race doesn't initially seat will I brace the fork with a wheel or 2x4. And I've done a bunch of each. More often I can hold the blade with one hand and whack away with the slide hammer. Andy

I think I get a better result with my padded tool. I get a solid seat and usually only one fairly gentle hit with my dead blow hammer since all of the energy is transferred rather than being absorbed by my arm holding the fork. If I am lazy and do not know where I put the tool, I hold the fork but instead of using my dead blow hammer, I use a brass mallet.

Why not turn it all upside down?

Sit, holding the inverted star nut setter on the ground between your feet. Hold fork upside down over that, place a wood block over the bottom of the steerer tube, and hammer that.

Use a dead blow hammer or something soft in case you scrape the fork legs, or use a really long wood block.