Strange system of measuring bore


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Posted by Chuck(G) on December 03, 2002 at 00:11:34:

Yes, I know that bore doesn't have all that much to do with anything. But...

Willson states that the bore of the 3400S Eb tuba is 0.750" (valves 1-3), 0.790" (valve 4) and 0.830" (valve 5). Seems pretty clear, right? So I took a pair of calipers and my 3400S and guess what?

Bore as measured: 0.700" (valves 1-3), 0.740" (valve 4), and 0.780" (valve 5).

Now, if I measure the OUTSIDE of the tuning slide tubes, I get Willson's numbers, but I submit that the outside diameter of a tube does not indicate bore (at least they don't measure rifle bore that way). A quaint Swiss custom, perhaps?

Anyone have a Willson euph or CC tuba and a set of calipers handy and want to post some numbers?


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