It can be done safely with a rubber mallet, a piece of wood and no small amount of care, for sure. It can probably be done with less care, no wood and a hammer too, but if you fuck up the headset you’re out more money than it would have cost you to get it installed, and if you fuck up the headtube you’re out a frame. A guy brought a bike into the co-op once who had tried to install his headset with a hammer and ovalized his headtube in the process, but he’s probably dumber than you are.
That said, I would suggest getting it done right at a shop. They’ll face and ream the headtube for you. If it’s a new bike, get the threads in the bottom bracket shell chased as well. These are both well worth the money and require tools you don’t have and can’t afford.
Also, with a file and sandpaper you can de-burr and clean the headtube, but it’s not the same as facing it.
Well I dropped $5 on all thread, nuts, washers and $55 on a 105 headset. While it was a little scary, I popped the headset right in. The guy at the shop did the crown race for free.
Once I get the cables on and everything snugged up tight I should be taking the maiden voyage!
Yeah, it’s really not that complicated of a process, any way you can devise to evenly apply the required pressure to get it in there will work. For home use, DIY options are just fine. I’ve gotten away with really sketch methods of installing crown races using a hammer and whatever tube like thing of the appropriate size I could find without problems. Using the proper tool is really only necessary for shops that would make use of it on a regular basis. This of course isn’t considering factors like user idiocy, not prepping the head tube, etc.
the even pressure thing was the hard part. If/When I do it again I’d choose larger washers and make sure the all thread was the same diameter as the hole in the washer to minimize wiggle!