Plastic Electrical Box

>>1123914
either you're not hitting it hard enough
or
it wasn't formed right and the thin areas are too thick

try hitting it harder near the edge at the connection points or between them

>>1123919
I'll try harder in a bit. I was striking it so hard with the chisel that the entire top would bend. Even holding it in a vice it would still give-in quite a bit. I imagine the fact that this is cheap hardware is having some play here.

>>1123923
put LID on BOX
put CLOSED BOX in VICE
take SCREWDRIVER, put on one of three points where it is held, sharp tap with HAMMER.
repeat with other two points (if needed)

Trick is probably keeping the box closed/lid on, oitherwise, it just deforms/absorbs your mighty blows. ahem.

>>1123926
Oh shit, I didn't even think about that!

>>1123914
As always this is a 2 part answer.

>op needs a bigger hammer.
>op needs a pecker.

>>1123919
>>1123926
>>1123935

It was a hole saw that finally did the job, and very well.

>>1123926
What's it like having a practical brain?

So many non practical autists - myself included, even on DIY.

Logic and practicality almost seem to be mutually exclusive. Or are you just autist with much practical experience?

>>1123967
was going to suggest hole saw, or hydraulic hole press, I haven't seen anyone use anything else yet and I work with those, good work i guess.

>>1123914
Electrical knockouts are not meant to be gently knocked out. The proper way is to tap a screwdriver with a hammer (I use pliers).
Here are some other tips:
>Drill a sheetmetal screw into the knockout and use pliers to pull the screw attached to the knockout.
>Use a hole saw or step bit.
I've also ruined flatheads with tough knockouts (waterflow switches are the worst). Now I carry a Chinese made spare.