Do Speedometers have an Oil Well?

[Cayuga Kid]

I was reading that the where the speedometer cable connects to the speedometer at the instrument panel that there is an oil well.

I have attached a picture and was wondering if this is a fact and if so what oil would I use. It looks like the well has a small hole?

Thanks

 

[Dan Scully]

Remove the small brass plug, there is a small reservoir. If the speedo starts binding it will fix it sometimes . And good to do if you have the speedo out . I use 3-1 oil.