For years electricians made large diameter holes in electrical boxes with knockout sets that were either manually cranked by a ratchet or hydraulically powered with a hand pump, hose and a lot of fussing. In recent years battery powered Knockouts have become much more popular because they are way more productive but a good GreenLee or Milwaukee tool set (even without any punch or dies) will put you back around $1300.
No questions these are the fastest, best option for high volume production but are a bit pricy for some to justify. We’ve seen the Mechanical Knockout tools growing in popularity in the last few years because they offer good performance, close to the cordless/hydraulic tools at a much lower cost. The Current Mechanical Knockout 163 ($549) is at a pretty attractive price point and with the full 1/2″-2” set Mechanical Knockout 162PM is only $779.
The mechanical knockout sets are less expensive because they cut the cost of a power unit, batteries and charger by utilizing a standard high torque 1/2” drill/driver. For those that already have a nice drill/driver or two (we’ll assume that’s you if you’re reading a blog about power tools) this probably isn’t a problem.
Current Tools are made in the USA and have performed very well from what we’ve seen. Almost identical mechanical knockout sets are available from Gardner Bender “Slug-Out” (see video below) and Maxis but both are higher in cost and don’t appear to be made in USA like Current Tool. We have not seen a GreenLee mechanical knockout unit yet but that doesn’t mean we won’t in the future.