Policy is on the Delta Pro website and is linked upthread -- https://pro.delta.com/content/agency...e-policy-.html
You can try and ask, but policy is that they will not check through on non-partners when booked on separate tickets.

As noted above, per policy TK is not listed as one of the carriers DL will through-check to across separate tickets. You will find anecdotes of data across FT of some travelers who have had success having bags through-checked to non-exception carriers but you cannot bank on this. You can ask at check-in and the agent may, as DL does have an interline agreement to check bags through to TK if on the same ticket, but the agent is under no obligation to through-check to the TK flight. in your scenario due to not being on the same ticket. As such, allow sufficient time at JFK to claim the bag and recheck with TK (plus transfer terminals which you'll have to do anyway).

Thank you ! I’m giving up the idea of delta to Turkish air. Too old to go to that much trouble!

Curious if OP has an answer on this now, thanks!

FYI, Poster hasn’t been on FT since May.

SAS
 

A question for anyone in the know:
I'm just curious if I would be able to through-check my bags on a DL itinerary with a separate (DL award) ticket from ARN on SAS ?

Per DL's through-check policy page, this *should* be doable: In cases as noted below, when more than one ticket is presented, Delta will continue to through-check baggage from the origin to the destination.

• SkyMiles Award plus a ticket with Delta-marketed / Delta-operated flights

https://pro.delta.com/content/agency...e-policy-.html

How long do you have between arrival and departure at ARN?

Just trying to figure things out as my final destination of AGP (residence, so therefore a frequent destination) is increasingly difficult to reach on Skyteam awards, since KL+AF route now primarily from CDG or AMS through Scandinavia on SAS and those connections are frequently with a nightly layover and sometimes even two stops. Hence, it would make sense to fly directly into ARN, CPH or OSL and take SAS from there on a nonstop to AGP.

I have two separate DL tix, dom then international. I understand that a bag can be checked thru, but, because of timing, will not have a printed boarding pass. Will the trip shown on the DL app suffice ? Or is there a better suggestion ? Maybe I am worrying too much.

Bring your printed itinerary.

Yes. You can also write on a piece of paper, the PNR#, flight # and e-ticket # for convenience of the agent.