Minimum layovers Atlanta and JFK?

Atlanta is a big airport physically. Even IF your flight into Atlanta is on time it will be close. You will arrive in Atlanta at one of the domestic terminals. If your flight to MXP is going directly overseas without another domestic stop, you will depart from the international terminal. Even if you are able to stay within the security zone and are able to take the plane train from one terminal to the other it will still be tight. Personally I wouldn't risk it. All you need is a thirty minute delay in arrival and all bets are off.

JFK is not as critical, imo, simply because you are coming back and if you miss the connection at least you are still "home" and can get another fairly short flight back to Columbus.

If your flight from CMH is on time you will make it. But I agree that is a tight connection if there is a delay in your arrival.
Check with Delta what is their policy in case the flight is late and you miss the flight to Italy. Obviously they will put you on the next day flight, but would Delta cover your hotel expenses in Atlanta? That is always my concern and that is why I avoid connecting in the U.S. when I fly to Europe from California. I prefer to go straight from California to a EU hub. Legally in the U.S. the airline is responsible for your hotel/meal costs only if the delay is the fault of the airline (mechanical issue) but not if it's due to act of God (weather). However Delta may have a different policy and cover your costs regardless. No matter what, missing the flight out of ATL would be very annoying because you would probably lose your hotel money in Europe for the unused night. Is there an earlier flight that would put you in ATL earlier?

I came from Rome to Washington DC with a 2 hour layover in JFK, it was more than enough, and as already noted, it's not as big a deal if you miss the connection as you're going home and a later flight won't be as disruptive to your plans.

Atlanta would be too close for my comfort. It takes a long time to get from one concourse to the other. Heck it sometimes takes 20+ minutes just to get off the incoming plane if you're in the rear. They will likely be boarding by time you get to the next gate, even if your incoming flight is on time.

Thanks for the info...as always!
My latest thinking ( I am going to drive myself crazy and will certainly NEED this vacation) is that flying through JFK in Sept would be safer than Atlanta in September....less likely for flights to be impacted by hurricanes?

I have yet to have a flight from JFK leave on time, in either direction.

If you are concerned about hurricanes, there are hurricane forecasts that you can check, but it's really a gamble.

I always choose the shortest allowed connections and it's always been fine. When the flights are delayed, usually either the other connecting flights are also delayed or they just rebook me and they'll get me there eventually.

My flights last summer, SEA -> AMS -> LJU were delayed two hours into Amsterdam. Everybody on the plane was freaking out because we all either had missed our connections or were really short on time. When we got in the terminal I typed in my reservation code at the first ticket machine I came to and I'd already been rebooked AMS -> CDG -> LJU. It printed me my new boarding passes and I was back in business. I don't think my delay was more than maybe 4 hours total after all was said and done.

My bags didn't make it until the next day though, but that happens all the time.

I prefer 2 hours in Atlanta. But depending on the trip, I will drive 2.5 hours to leave directly from ATL to reduce the number of flights on my trip.

I wouldn't worry about hurricanes in ATL. It's several hours inland!

Leaving from VCE is usually a pain. Most flight to the U.S. leave early in the morning, which means getting up early to get to the airport. Better to fly into VCE.

Yes, I realize Atlanta is "inland", but if there is a hurricane playing in the Atlantic Ocean, flights will most likely be disrupted. We flew to San Juan in September a few years ago, and sat in Charlotte's airport for almost 24 hrs due to weather in the Atlantic. Just trying to hedge my bets! :)

Flights this September from VCE to CMH depart 11:30 and 1330 directly to the east coast where we would connect to get home....but I agree, the 0730 flight from VCE would require an early wake up call!