I ordered one of these from Ali Express for $60... what could go wrong?
I went for the 1" to try out, will probably get a quality 1.5" dimple die elsewhere.
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Well, the 1" knockout & die from Ali Express (China) arrived today, it was $59 with free shipping. The knockout & die came with 2 bolts, which is a good thing. The parts are all heat treated, so hopefully they'll last awhile.
I was pretty excited, so I found a piece of scrap sheetmetal and started playing around. I drilled a hole with a step bit (about 1/2"), applied Anti-Sieze to the threads and a bit of lube to the die itself, as
@Vonski suggested. The piece of scrap wasn't perfectly straight and my layout of the holes wasn't perfectly in line, I was in a hurry and since this was scrap I wasn't too worried about things being perfect.
I grabbed my 1/2" impact and started tightening the bolt, which just threads onto the opposite die. It cut quickly and pressed the sheetmetal in the die relief, but after taking it apart it was obvious that it didn't shear all the way around. I ended up bending the leftover edge back & forth by hand until it came off, then touched up the cut with a flap disc on the grinder.
I ended up punching 4 holes with the 1" die, then bend the edges up in my little sheetmetal brake. It's amazing how rigid that piece of scrap sheetmetal has become! I really dig playing with the dimple dies, I can see this being a fun tool to integrate into my work. This little piece took me less than an hour to knock out, not bad for my first time using it. Going to add some other sizes to my collection and try different methods to cut the hole.
I feel like over time the threads on the bolt & die might strip out and the cutting edges of the knockout will dull.... they say you can use a press, might try that next. For the price, it's worth considering.