I don't have one, but do have plenty of the other stuff :) It's also easier to injure yourself with an angle grinder, plus it's pretty noisy and messy :P If we assume the safe operates in a reasonable fashion, that it can deal with 4 key presses a second it'd be possible to exhaust the combinations in less than 9 minutes. This also has the added advantage of not destroying the safe :) I've not seen a digital safe intended for home use that rate limits unlock attempts.