Buffet Crampon clarinet : difference between RC and E13

In November 2017 MRO saxophones overhauled two popular clarinets of Buffet Crampon at the same time. That was also a great opportunity to finally determine exactly what the actual differences are between these two types. The RC is considered the entry-level professional model; the E13 as an Intermediate model. Because I overhauled both types before, I already thought that the differences were minimal, especially with the older models.

The RC with serial number F325190 and the E13 with serial number K144848 are both silver plated and already on age. An E13 with prefix K actually has the 'old' serial number range of the Evette Schaeffer: the predecessor of this model.

After thorough study of both the keyswork and the wooden main parts I noticed (as expected) hardly any differences. keys from both parts are interchangeable and identical, except for the RH B valve. All tone holes are identical and of equal diameter.

Here are the two differences:
1) The bore is minimally different (14.90 - 14.70 for the RC and 14.90 - 14.55 for the E13).
2) the RC uses an axis for the RH B valve on the lower main body; the E13 uses two pivot screws here. Also the stud on the wooden part is slightly different (see last photos). At the E13 the distance between the two studs is longer: the left stud is fixed with a screw.

On the photos the RC is shown above and the E13 below.