Grant Erwin wrote:

... If I order a 3/4" bore 5" pulley from MSC it will also be made by Chicago Die Casting
and it will also measure 5" across the OD. ...

OK, it seems to be a mixed bag at McM-C: it asks you for the OD when
searching, but the catalog page does show the pitch diameter. BTW - for
3L belts the pitch diameter is 3/32" less than the OD. For 4L, A, & AX
belts it is 1/4" less & for 5L, B, & BX belts it is 1/2" less.

Bob