I spoke with Andersen and they no longer sell parts. I need corner pieces for the 2852 window. If you have hatchet blade device for seating screen into window frame, I would be interested in that as well.
I have attached a picture. The corner looks like the over-the-counter one on the bottom right but is narrower. Let me know what kind of measurement you need and I will email back.
Thank you,
Mary Anne