Maybe some of you who have moved abroad could help with this question.

I am planning to take an antique sea chest with me on the airplane from Germany to the US. Empty it won't exceed 35kg, but it is bulky, L+W+H=390cm.

Still I imagine the overweight charges will be less than freight costs?

Your airline web site should have the data you need. Compare any excess costs to the cost of shipping it air freight.

Aha, thought of that, hopscotch. Did not find it easy to get that info from German air cargo websites so this seemed simpler as a start.

Really hoping someone has experienced a similar situation and found which transatlantic airline(s) are easiest to deal with and have the lowest overweight/outsize luggage charges

I used KLM air freight from AMS to LAX for a couple of way overweight duffel bags. It was much cheaper than excess luggage fees. KLM has a convenient air freight office in Schiphol near the check-in. Everyone speaks English, and they were very helpful.

Thanks Hopscotch,

Schipol would be great, but the monster box is in Hamburg

If it's antique, it will need to be protected. Do the measurements include protective padding?