Bolens used the same part numbers for same parts, regardless of what they are used on.
The blade spindle assemblies (bearings, shaft, housing, etc.) are commonly used between the 42" Tube Frame decks 18420, 18421, 18423, 18457 and the early model Large Frame decks 48" 18048 and 18049-01-03, 54" 18070 and 18071.
The 32" and 38" Tube Frame decks don't share much of anything with the Large Frame decks, other than some common hardware such as nuts and bolts.
The real confusion comes into play when a part # has been superseded and only the new part # is printed in newer model manuals, even though it is still the same part as used on the older models. I'm hoping to help supersede part numbers in the database as time allows me.
Edit for clarity: I should note that the blade spindle pulleys ARE NOT interchangeable between the Tube Frame and Large Frame decks.
Edited by ClassicBolens, March 06, 2016 - 12:33 PM.