Stumped Over Tub Drain Insert

[acc]

I live in a high-rise building built in the mid-60s in Chicago. I am trying to replace my bathtub drain insert, but I'm having a hard time finding one that fits. I'm not sure what the thread is, but it's much finer than course and it's about 1 1/2". Since everything is set in concrete, there's no way to replace the fitting below the tub. Can anyone give me a lead on what kind of thread I should be looking for and where I can find an insert like this? My local plumbing supply places don't stock anything like this.

Thanks for all your help!

Samantha

 

[Jimbo]

You will need to determine EXACTLY what diameter and thread pitch is it, then check Chicago Stamping and Bending http://www.macristyindustries.com/ or Watco http://www.woodfordmfg.com/Watco/PDFMainFrame.html

 

[Sponsor]

 

[Jc60618]

Can you post a pic?