From the first three articles, someone could easily put together a home shop to do 75% of the repairs on their bike. But once you get past the surface of adjustments and basic components, it is gonna take some pretty large and expensive tools to start working further.
A lot of home mechanics have low-buck ways of replicating these tools, and those methods probably work. Coming from a shop background though, we recommend using the right tool, or taking it to a shop. While you might save money making your own headset press from threaded rod, nuts and washers, the cost savings evaporate if you accidentally wreck that new Chris King headset. A proper headset press will keep the surfaces parallel, and with the proliferation of press-fit bottom brackets, they now double as BB installation tools, so much that Park re-named theirs “Bearing Cup Press” instead of “Headset Press”.
A caveat applies to this post in the series, that all these tools need proper training. Any of these large special tools can do a lot of damage if used wrong, so if you don’t know what you are doing, it would still be best to pay a pro for installation or removal. Or take a class.