A method of producing an elongated component of glass, said method comprising heating a bulk glass component in a heating region at a temperature; drawing a strand from the bulk glass component at a forming region of the bulk glass component ; using a pulling device comprising a motor configured to exert a pulling force on the strand to control the rate at which the strand is drawn from the bulk glass component ; characterized in that the pulling device is configured to exert a pulling force on the strand in both a direction aligned with a gravitational force and a direction opposite the gravitational force, wherein determining the pulling force (F p ) applied to the strand by the pulling device comprises: (i) measuring a voltage applied to the motor of the pulling device, measuring a torque applied by the motor to wheels ; and calculating the pulling force (Fp) from the voltage and the torque, or (ii) measuring the output of load cells applied to the pulling device , determining the mass of the strand based on the cross-sectional area A and the density p and the length L of the strand , calculating a holding force (F h ) applied to the strand by the forming region by determining the algebraic sum of the gravitational force F g and the pulling force F p applied to the strand , wherein the gravitational force F g is calculated using the determined mass of the strand ; and determining whether the holding force (F h ) is equal to a desired holding force (F h ) based on a desired viscosity of the forming region ; and adjusting the temperature of the heating region if the holding force (F h ) is not equal to the desired holding force (F h ). heating a bulk glass component in a heating region at a temperature; drawing a strand from the bulk glass component at a forming region of the bulk glass component ; using a pulling device comprising a motor configured to exert a pulling force on the strand to control the rate at which the strand is drawn from the bulk glass component ; characterized in that the pulling device is configured to exert a pulling force on the strand in both a direction aligned with a gravitational force and a direction opposite the gravitational force, wherein determining the pulling force (F p ) applied to the strand by the pulling device comprises: (i) measuring a voltage applied to the motor of the pulling device, measuring a torque applied by the motor to wheels ; and calculating the pulling force (Fp) from the voltage and the torque, or (ii) measuring the output of load cells applied to the pulling device , (i) measuring a voltage applied to the motor of the pulling device, measuring a torque applied by the motor to wheels ; and calculating the pulling force (Fp) from the voltage and the torque, or (ii) measuring the output of load cells applied to the pulling device , determining the mass of the strand based on the cross-sectional area A and the density p and the length L of the strand , calculating a holding force (F h ) applied to the strand by the forming region by determining the algebraic sum of the gravitational force F g and the pulling force F p applied to the strand , wherein the gravitational force F g is calculated using the determined mass of the strand ; and determining whether the holding force (F h ) is equal to a desired holding force (F h ) based on a desired viscosity of the forming region ; and adjusting the temperature of the heating region if the holding force (F h ) is not equal to the desired holding force (F h ). <EOS>