Fidelity Research FR-54 Tonearm. ANTI-SKATE???

Elliot, thinking about it, I would not grind that weight down. I would just make a new anti skate bob with some light fishing line and lead fishing weights. Lead is very soft and easy to trim. 

Mike

Elliot, there is no direct relationship between tracking force and the weight of the anti skate bob. I do believe there was an add on weight that threaded into the bob. At any rate, set up your cartridge and tonearm. When you place the needle in the run out area between the grooves the tone arm should drift very slowly toward the spindle. If it starts drifting out ward you have too much anti skate for the tracking force and you will have to figure out a way to lighten the bob or replace it with a lighter one. The other option is the increase the tracking force to the upper limit the cartridge is specified for and see if you can get the right drift. If the tone arm drifts quickly toward the spindle you will need to add weight which you can do with 3M double sided mounting tape and any piece of heavy metal such as a nut that matches the diameter of the bob. 
This is not an exact science. As long as you get that slow drift towards the spindle you will be fine. If you want to be more exact you will need a test record with ant skate adjustment bands like the Hi Fi News test record.
The last option if the bob is too heavy is to get a cartridge that tracks at a heavier force. My guess is that the arm was tuned for the usual Japanese MC cartridge tracking at 2 to 2.5 grams. 

Exactly. Make that lighter weight and see how it tracks the run out area between grooves. It should just barely drift towards the spindle. 

Elliot has already proven that the anti skate is too heavy for a VTF of 1.5 gm. He put the stylus down in the run out area and it immediately drifted out.
Elliot, just for fun disable the anti skate by lifting the bob up with your finger and place the stylus down in the run out area again and watch it drift right towards the spindle.
Now just make that lighter bob with your fishing line and tell us how it works. Nothing like the power of observation.