When I say cheap, I mean this thing is only $34.98 on Amazon. I ordered one a while back because I was in a bind and needed a cheapy tool to get me by. I decided to keep it as it was not actually that bad. I have used expensive Glock rear sight tools like one from Trijicon and Ameriglo sure they works perfectly, but it is also around 3-4x the cost of this tool. After a recent discussion on Pistol-Forum.com, I decided to take a short video and post it up as a quick and dirty explanation of what the tool does, what to expect from it and what it does well and does not do well.
#1 - The pieces that seem to move about easily/freely require you to fasten them place somehow. I normally use tape for the large metal block on the bottom (100mph tape).
#2 - The little skinny piece needs be there because it helps push Glock slides up a little bit to allow the pusher to function. So you can tape that if you want to, but you may need to remove it if you use it for other pistols (Sig, for example).
#3 - While you can hand tighten the slide into the fixture, I would highly recommend using torque of some kind.
#4 - both sides of the pusher assembly move the pusher back and forth depending on the direction you want to go. The issue is that you should only use the side which is not the nut with washer but the screw head itself. You can actually untorque the screw nut (as I showed) and you'll have to retorque it in order for it to function. You also should use a bit of loctite as it does not need to be free for any reason (I loosened it for purposes of the video).
#5 - As you can see in the video I have a very large adjustable wrench. You can use a socket set if you want to, this is just easier for me as I already had it around. I also dual use it as a torquer for the slide. A half turn is completely sufficient to torque the slide in place and then you will have to use it to loosen the slide out.
#6 - you can use this tool without the gun being disassembled. You can just lock the slide to the rear and blamo, works fine.
#7 - I have used this particular one for about two dozen rear sight changes on various Glocks. I even used it to install one of the Dueck Defense RBU's I have.
#8 - Once you are done using it, lock everything back in place - torque the slide cubes in place and it'll be good to go for next time.
Realistically, for the amount of rear Glock sights I change and how often I change them I should invest in a really nice pusher like the one from Ameriglo (my favorite in terms of ease of use) but for less than $35 it was hard to say no. I figured if it breaks I will buy the expensive one I want, but it has not yet and judging from how well it works, I doubt it will any time soon.