TV set tubes are " picture tubes" and use very high voltages (10 to 25 kV) for beam acceleration and focusing and have NO internal plates for beam deflection. That is done with magnetic fields produced by coils mounted on the neck. They whole design is intended to produce a "raster" on the screen with hundreds of horizontal lines.
For playing around, you really need to get a small * scope tube * - the voltages used are far more manageable ( 500 to 1kV) and deflection is electrostatic and hence uses only low voltages and virtually zero current.
This page has some interesting circuits for very simple scopes: