Matching data using date criteria...

I have data entered into 2 separate databases:

DB A: roll_num, plate_date (step 1 of process)
DB B: roll_num, cut_date, cut_num (step 2 of process)

cut_num is unique for every data entry, but the roll_num stays with a roll its entire lifetime, therefore repeating several times in the data tables.

What I want to do is link the data sheets together to form one master table. This could done by taking the roll_num and cut_date in DB B and matching it with the closest previous roll_num and plate_date in DB A. My problem is that I have absolutely no idea how to do this.

Any suggestions? Sorry if this is unclear...I'll explain better if needed.

Thanks, Joe Z

Anyone have any ideas?