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What is in the black box, anyway?


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Long story short, the 18v right angle grinder stopped working, but bypassing the silver electronics module started the motor right up.

Therefore, what does that thing do?

I am guessing that some refer to a clutch in the tool, and not seeing one, the box may sense a near stall condition and lock out.


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I think at some point I'll pour some de-potter in there and see what they hid.

For now, though, it works just fine absent the magic box. Granted, I haven't tried to cut 3/8" steel plate with it, but I don't envision that thing for that kind of work. Makes small quick cuts fine, no load sounds right and doesn't overheat it. I dunno.


I am going to see if I can upload some of the pics I took to save you the trouble of breaking yours open... stand by

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well, there it is in all it's naked glory!


It takes a Torx with the center hole (sorry, I forget the size) in every position EXCEPT the lower one in the base. It is one size smaller. Why? Who knows, but it certainly was frustrating!


To split it, you bust out all the handle screws, then the four screws in the angle head that point into the handle. These are tricky. Then pull the angle head off. The clamshell will then seperate fairly easily and nothing will pop out.


Be very careful, if you yank the brush holder off, you'll need a pencil or something similar to depress the brushes to reinstall them.


Whatever that box does, it affects the ground side. I simply cut the box out of the circuit path, extended the black wire, and put it where the box terminated into the switch.


Now, on the newest Milwaukees, there is current needed on more than one terminal. I do not know which other terminals it is. I suspect there is a signal path for a temperature sensor buried in the lithium pack you're supposed to use, but with the way mine is set up, I can't advise.


Because that box is removed, you probably should be careful about duty cycle. That thing might prevent you from burning it up by too much torque (really getting into a cut or brushing) or running it too long without cooldown periods.


All I know, and my small contribution to this site!




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WOW! Talk about a great conversation starter!!!! I wish I could help but when I saw the post my mind went to that dark place.... :P

Do you know how a bottle blond is like a commercial airliner? They both have black boxes.

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