Upvote:5
According to Copa's baggage policy between the United States and Brazil and you're traveling economy, you're allowed two checked pieces. Each must weigh 32 kg / 70 lb or less and the total linear dimensions cannot exceed 62 inches / 158 cm.
I randomly chose a Stanley 50 gallon mobile tool chest to check dimensions and weight. Final assembly size is 37.00 x 23.00 x 23.00 inches and weighs 40.625 lb. Because the total linear dimensions is 83 inches, you'll have to pay a $150 oversize bag fee. If you go over the weight limit, you'll get a $250 overweight fee and can only go up to 99 lb / 45 kg.
Note: I found the Husky box you mentioned, "37 in.", and the dimensions are the same as the Stanley one I used as an example.