Newbie Question - What is "Overhang"

I know that I probably shouldn't be asking and some of you are probably rolling your eyes. I understand cartridge alignment, but what is "Overhang" exactly? and how do you know if its off using the Rega alignment tool? If I got the turntable basics alignment tool how would that tell if the overhang is off?

It's when I can't see my toes. Happy New Year!
When you have set the correct tracking force, and place the stylus on the alignment gauge, the stylus should be directly on the cross-hairs. If it is over or under, you will not have correct overhang, and it will affect the tracking performance of the system.
Overhang is a term used to describe the incorrect tracking path of the stylus for cartridges mounted in a pivoted tonearm. Overhang is not a problem with linear tracking arms, which track in a straight line directly across the record (the same path followed by the cutter head when LP masters are cut). Ideally, the stylus (in pivoted tonearms) ought to trace an arc that is tangential all the way across the LP, but that is not possible due to the relatively short length of the tonearm. Therefore, a stylus will only be "perfectly" tangential at two points along the arc it traces.

For the arc to be as accurate as possible, the cartridge must be mounted so the stylus will follow the desired arc. If the cartridge is mounted too far forward on the tonearm, however, the stylus will "overhang" the path of the desired arc. If the cartridge is mounted too far back on the tonearm, the stylus will fall short ("undershoot"?) of reaching the desired arc.

Hence, one of the main reasons for using a cartridge/stylus alignment device (or protractor) is to ensure that the cartridge does not "overhang" or "undershoot" the desired tracking arc. Getting the correct adjustment is not particularly difficult, although it can be tedious even with a good alignment tool.

There are several cartridge/stylus alignment tools that work reasonably well: the Dennesen "Soundtracktor" and the MoFi "GeoDisk" (both of which are no longer distributed, but can sometimes be found on the used market); the phono cartridge alignment tool sold by Turntable Basics (see this link for more info:; and the rather expensive device called the Wallytracktor, which is custom made for the specific tonearm/cartridge setup that you own.

I have the original plastic version of the Dennesen "Soundtracktor" and it works quite well. If you can find one, buy it. If not, then the tool from Turntable Basics does an acceptable job.
Sdcampbell, would the RB300 be claissified as a "pivoted Tonearm"?
Yes, the Rega RB300 is a pivoted tonearm (as are all of the Rega tonearms). Linear tracking tonearms are very distinctive: they have a base which extends across the back of the turntable, and the cartridge is mounted to an arm that tracks perpendicular to the LP (imagine the cartridge following a straight line from the edge of the LP directly to the center hole of the LP).

There are very few linear tracking arms still made, so virtually every tonearm on the market today is a pivoted design. The design of the pivot itself usually falls into one of two categories: a unipivot (such as the Graham 2.2), or a ball bearing type such as the Regas.
TWL and Sdcampbell, Tell me if I'm correct.

1. When placing the stylus on the Rega alignment tools "cross hairs" the headshell at this point should be square with the printed lines.

2. If the stylus is on the "cross hairs" correctly but the headshell is not square with printed lines I then have incorrect overhang because If I were to try to square the headshell with the printed lines then the stylus would either be too far back or to far front of the "cross hairs".

That was a mouthfull,
SdCampbell, actually overhang exists also for linear trackers. You still need to position the stylus correctly along the arm otherwise you will be off tangent for the whole disc, negating one of the advantages of linear tracking!