My metal threaded fittings that go through the sink bottomholes all rotted out. I purchased a double drain plastic assembly that Ithought was going to be a piece of cake to replace. However, my drain holes are1 3/4. The threaded parts that goes through each of the two holes on the newassembly are too big- 1/7/8. Every parts place in the area have the same width.Did they change the hole openings or are they not standard opening sink model to sinkmodel? I was thinking of using a drill drumel to evenly make the openings 1/7/8 and then just using plumber’s putty. Before you ask, I did scrape away allthe old putty and the opening is truly 1 3/4.
Or should I look around nationally to see if I can find a laundry double drainassembly that works for a 1 3/4 inch opening?
Just to clarify, this sink has no build in treads to the holes like the new ones. It's just flat openings on inside bottom and outside bottom of the sink.

If you can't find a replacement part that fits then using the dremel tool with a sanding drum shaped attachment should allow you to complete the job properly. I would suggest using goggles and a face mask and I would also suggest using a silicone caulking here (putty is fine, but silicone, if let to sit for the required dry time is better job).

Happy Holiday!

Mark

Some of the older laundry trays did have a smaller drain. However, they normally don't have an overflow so Marks suggestion is a perfect answer.