No Weslock and Schlage handles will not be interchangeable. And Schlage would only be interchangeable if the series were the same. They are not universal.

Thank you. It sounds like I might need to swap out the whole entry handle then, as the only lever that goes with the Plymouth entry handle is the one I already have. Or I can just leave the two problematic handles (front door and garage door) but that seems kind of icky.

Is this true even if no lock is involved? I'm just not sure that series applies to entry handles that don't have a lock. Thanks again.

" Is this true even if no lock is involved? "

98% are not interchangeable brand to brand or even series to series. This is done intentionally.

I spent a bit more time researching this yesterday. I finally came to understand what you meant about series. The current exterior handle is an F series and I didn't like any of the interior handles that go with it. Then I discovered that the same exterior handle (the Plymouth) now comes in the Custom series as well. So I ordered the Plymouth exterior handle (just the handle) and the Eller interior lever, both in the Custom series. (Both came with a deadbolt, which I don't need.)

Because the front door is right next to the coat closet, I needed to get an Eller hall/privacy lever for that. They are quite expensive (I paid far more for the front door combo than I would have liked!). But I got lucky and found an open box one on eBay, made an offer that was accepted.

Thanks so much for your help! I know more about door handles than I ever thought possible!