Conn bore question

[350 Rocket]

There's something I've long wondered about Conn clarinets. I have three Conn student models (1958 composite 14N or 50N, 1961 wood 18N, and a 1964 16N) and all three have a bore diameter of .605" at the top of the upper joint and .590" at the bottom. However, while the barrels are .590" at the top they're no more than .585" at the bottom. When assembled there is a visible "step" in the bore where the barrel meets the upper joint. The 16N's barrel is definitely original, the other two can't be positively confirmed but the socket rings match.

What is this considered? Reverse taper? Polycylindrical? What's the reason for an immediate .020" or so difference where the barrel and upper joint meet?

[Windsong]

Odd.  Aggregious error, perhaps?   I have found on my B&H clarinets, that whilst the bore taper between joints is quite good, there is some discrepancy in the barrel section, as well.
It does not adversely affect pitch, which means it was designed this way, or they got lucky in their erroneous design(s).

[350 Rocket]

Odd.  Aggregious error, perhaps?

That's what I thought with the '58, but when I found the other two to be identical, I expected it had to be intentional.

The 16N plays wonderfully for a plastic clarinet. So well that, even though I bought it to repair and resell, I decided to keep it. Conn seemed to have spent a lot of effort designing and engineering it, it seems odd that they'd've overlooked something as fundamental as the bore.

[mechanic]

I have what I believe is a 1963 Director.  The body is not marked except for the serial number.  Very faintly on the bell I can make out part of the Conn and Director.  The posts on the lower joint have the Conn set screws and the serial number comes up as a 1963 per the lists.  It also came in a Conn case that has that 60's look.


Top joint is .605 at the top and .593 at the bottom.  Barrel is .590 at the top and .583 at the bottom.  Top of the lower joint matches up nicely with the bottom of the top joint at .593. 


Looks more and more like this is design, not error.

[windydankoff]

That is about consistent with the Conn 16 I had (made of Zyloid plastic). I didn't care so much for the tone. I sold it to a fellow who doubles in a jazz band and wanted something loud. He loves it.

Now I'm hooked on the Pruefer, which has a less-large, straight UJ bore.