I bought an old Supreme Push Pull Tapper a while back and today I got to put it through its paces threading 32 M6 holes in steel and I have to say I love this thing. It took much longer to drill the holes than to thread them, which hasn't ever been the case before. Though it works very well in a drill press I threaded those holes with it chucked in my hand drill and all were perfect, without using any tapping fluid. The Push Pull is impossible to hold when the tap starts to bind, and it stops turning the tap, and you know immediately that it's time to reverse a bit and clear the chips. This makes it very safe threading and broken taps will likely be much less frequent or perhaps eliminated, we'll have to see as time goes on. This just became my favorite tool.
Here's a video of one in action, though I have no idea what all the starting and stopping is about in it because I used the anti-blather control when I watched it. Routine threading is straight forward and much quicker in normal practice. If you watch Ebay you'll likely find one and I give it .