Take a look at your guitar tuners. See how tightly they are pressed into the pegholes? Well, most tuners aren't actually pressed into the pegholes of the headstock. Most tuners sit in bushings that are tightly fitted to the pegholes. These bushings hold the tuner in the center of the peghole and help maintain the tuner's stability. You might ask, with the tuner bushings set so tightly in their holes, how do you install them? A hammer is the wrong answer. If you try to install the bushings with a hammer, you will not only damage the bushing you will probably damage the headstock as well. The tuner bushing press is the best tool to press in tuner bushings.
After the pegholes are drilled and counterbored the tuner bushing can be installed with a bushing press. A tuner bushing press is basically a set of vise grips with a special fitting on both jaws. One jaw has a flat edge to go up against the back of the headstock. This edge protects the back of the headstock from being dented by the vise grips. The other jaw has a fixture that attaches to the bushing. The bushing fits into the fixture and can easily be pressed in place with one squeeze of the vise grips. Make sure after you have pressed the bushing in place that it is evenly pressed and the bushing lip is touching the top of the headstock all the way around.
You can also use a C-clamp to press your bushings in place. Take a C-clamp and place two pieces of plexi-glass on each clamp. These pieces of plexi-glass with protect the headstock finish from the C-clamp denting it. Line up the bushing and turn the C-clamp until it is pressed into place.
Hand tuner bushing presses are great to use if you don't have a drill press. Personally, I prefer just to use a drill press to press in my tuner bushings. It is easier on my hands and easier to line up. To use a drill press, simply remove the drill from the spindle and tighten the jaws all the way. Now place your headstock on a flat block under the spindle. Put the bushing squarely in its peghole and give it a slight tap with the drill press. Then take a look to see if the bushing is lined up properly. If it is, press it the rest of the way in with the drill press. This is much easier than using a hand tool.
Guitar tuner bushing presses are nice. They work well for what they, but I don't think that you really need to spend the money to get one. You can make your own tuner bushing press with a C-clamp. You can also just use your drill press to press in the bushings. I don't really see the need to buy a tool that you don't really need. Plus, I have found using a C-clamp and using a drill press is easier than using a vise grip style tuner bushing press. So go convert your C-clamp into a press and install some tuners! If you would like more information about how to replace guitar tuners, please see my how to replace guitar tuners article.