[ed morini]

I gave up using commercially made thresholds as they never held up usually red oak, laminated and even with linseed oil were useless.
I would recommend a run to Downes and Reader, buy 8/4 dressed White oak to 1 3/4", I think they may have it in the retail rack, and make your own.

I have no affiliation with D&R just been a customer since day one.

If by "People's Republic" you live in Cambridge go to Anderson Mcquaid on Fawcett St.,they literally have everything.... may even have old school white oak thresholds

Ed