The Dictionary on my computer is wrong...

I have a dictionary as a screensaver on my Mac, and this was one of the definitions for today:

spline |splīn|noun

1 a rectangular key fitting into grooves in the hub and shaft of a wheel,esp. one formed integrally with the shaft that allows movement of thewheel on the shaft.

• a corresponding groove in a hub along which the key may slide.

2 a slat.

• a flexible wood or rubber strip used esp. in drawing large curves.

3 (also spline curve) Mathematics a continuous curve constructed so as to pass through a given set of points and have a certain number of continuous derivatives.

verb [ trans. ]secure (a part) by means of a spline.• [usu. as adj. ] ( splined) fit with a spline : splined freewheels.

ORIGIN mid 18th cent. (originally East Anglian dialect): perhaps related to splinter .


I spent enough time working in the family hardware store (and sold pulley shafts and a spline or three) to know that this is flat out wrong. The spline is actually there to prevent movement of the wheel on the shaft, that is, to force the wheel and shaft to turn as one assembly.
Has anyone else found an obviously incorrect dictionary definition?
Or, am I just somehow reading this wrong and misinterpreting something?

 

I'm reading it the same way that you are. The way my brain works, that definition sounds wrong.

 

The dictionary on the Mac uses Oxford as a source:

Definition of spline in Oxford Dictionaries (British & World English)

I think the problem here isn't that it's wrong but that it's poorly written. I think it's meant to suggest that the spline allows the wheel to move when the shaft is turned. Otherwise, how could the wheel turn independent of the shaft when it's fastened with something "formed integrally" with the shaft?

To answer your question, I haven't found errors, but I have found entries that could have been better written.

 

It should probably say that it causes the wheel to move in conjunction with the shaft instead of saying what it does.

 

This makes me think about my word choice even more carefully. Seems that it's incredibly easy to phrase things improperly to the point where they are incorrect.

 

It's not uncommon for me to edit a sentence because it could be interpreted in at least three different ways. These are often longer compound sentences that simply need words taken out and/or rearranged.

 

I thought that the best answer to this would come from talking to a blacksmith rather than a wordsmith.
Knowing no blacksmiths, I talked to an engineer at the Nebraska Tractor Testing Laboratory,the only tractor testing and evaluation facility in the USA, and the Larsen Tractor Museum,who said in effect that the Oxford definition is way off the mark and has it just about backwards, especially the "formed integrally" part.

• The spline does not just allow the wheel to turn with the shaft, it forces the wheel to turn with the shaft, keeping the shaft from turning independently of the wheel. A simple friction fit would allow the wheel to turn, until some coefficient of friction is passed, and then the shaft would turn inside the wheel.

• If the shaft and wheel are integral, then no spline is needed (or even possible) because the assembly is all cast or machined in one piece. If the assembly is integral, the only thing that would allow independent movement would be breakage.

• If the wheel rotates on it freely, (like a wagon or bicycle wheel) it should be called an axle.

• If the wheel turns WITH it, it is called a shaft.

• There was then some talk about "driven members" vs. "driving members" which started me to thinking about sex.

And never wanting to miss out on a wordplay, I think this address is funny, especially considering Oxford's take on the ORIGIN of the word spline.
ORIGIN mid 18th cent. (originally East Anglian dialect): perhapsrelated to splinter.
Nebraska Tractor Test Lab
134 Splinter Labs
35th & East Campus Loop
P.O. Box 830832
Lincoln, NE 68583-0832