www.shulercue.com
The website has changed quite a bit, and the info may be harder to find than before. Manwon has given a great explaination, and I wanted to add a bit of my limited experience, too.
As you mentioned, re-cutting, or resizing a billiard cue to a smaller diameter is not a problems, Just copy the taper down to the smaller tip diameter, and adjust a bit to alittle longer taper...not much.
I have included Mr Shuler's quote from the website for a better explaination of tapers on shafts for you. Good Luck
RWOMEL
S Texas
Ray Schuler comments on cue shafts
"The taper, or profile, of the shaft is probably the single most important determinant of a cue’s performance. The term pro or professional taper has come to define a shaft that, instead of being tapered, is cylindrical from the ferrule back for 10 to 14 inches, sometimes more. This type of shaft taper is more or less standard on modern pool cues. As an engineer, I consider it a serious design flaw.
"Herman Rambow is credited with inventing the pro taper. But I visited Herman’s shop many times and knew him well, and I know that he never made a shaft that wasn’t tapered along its entire length. The taper was so minor in many cases, however, that you couldn’t feel it. Consequently, when cuemakers came along who wanted to imitate Herman’s cues, they mistakenly thought his shafts were cylindrical for some distance back from the tip. Hence the ‘modern’ pro taper.
"At The Schuler Cue, we offer a variety of standard shaft tapers, but every Schuler shaft grows in diameter from the ferrule on back. The growth may be difficult to see or feel on some of our more flexible tapers — such as the Super Pro or Super X — but it’s there, and it’s important. You lose a tremendous amount of consistency and strength when any part of the shaft is cylindrical instead of tapered.
"Wood is a natural material, and as such its structure is inherently inconsistent. It is virtually impossible to find absolute consistency of density, grain, cell structure, bend modulus, or color from one end of a shaft to the other. The less taper a shaft has — the closer to cylindrical it is — the more pronounced will be the effect of these natural inconsistencies on shaft performance.
"For example, every shaft has a natural, built-in tendency to want to bend in a particular direction and at a particular point along its length. Taper on a shaft helps the cuemaker control those tendencies, so that the shaft will bend where it has been designed to bend, instead of where it wants to bend. Conversely, the absence of taper decreases the control that the cuemaker, and the player, can maintain over the natural inconsistencies in shaft performance."