Newall bases their scales size on reading length, not overall length.
To get the correct size scale, you need to measure the overall length of the scale and then subtract 10". For example, on your 48" Bridgeport, your scales' overall length is going to be 38" so to get the proper scale you will subtract 10" and order the 38" scale.
If you have any questions please call 1-800-285-5271 ALL NEWALL SCALES ARE 17-22 DAYS BACKORDERD AT THE MINIMUM