09-05-2012, 05:34 PM
The 38's are 15" machines. And the 48's are 19" machines. In doesn't matter about the other letters that may have been added to the model - the designation 38 and 48 remains the same. In fact that number relates to centimeters. All 38's / 15" models are rated at 620 rpms, and most of the 48's / 19" models are rated at 400 rpms. The exception is on the 48DF's (Diamond Finishers) which spin at 800 rpm's.
Now when you're looking at rpm's what's being measured is the brush speed, not the revolution of the drive-deck (or bowl). The drive-deck rotates at about 1/3 the speed of the brushes. So the brushes should be spinning at roughly 400 rpm's on the 48's and 620 rpm's on the 38's.
Hope I explained it clearly enough.
Now when you're looking at rpm's what's being measured is the brush speed, not the revolution of the drive-deck (or bowl). The drive-deck rotates at about 1/3 the speed of the brushes. So the brushes should be spinning at roughly 400 rpm's on the 48's and 620 rpm's on the 38's.
Hope I explained it clearly enough.