
Model 35 Viscometer Instruction Manual
208878
Revision N, February 2013
21
5.4.3 Torsion Spring Removal and Replacement
Refer to Figure 5-4.
1.
Remove the dust cap [A] and plug screw [B].
2.
Loosen set screws [C] and [D] about one-half turn. The spring can now be
lifted out. Be careful not to stretch the spring.
3.
Insert the new spring, making sure the bottom mandrel is properly oriented
and seated. Set screw [D] should line up with the point at which the spring
leaves the bottom mandrel. A notch cut into the upper end of the bottom
mandrel will help locate this point. Tighten set screw [D], so that it presses
against the split ring to hold the bottom mandrel of the spring.
Before tightening the set screw [C], make sure that the top of the
adjustable mandrel is flush with the top of the clamp [E]. You may
need to slightly compress or stretch the spring to accomplish this.
4.
Tighten the set screw [C]. The slot in the top of the adjustable mandrel
should line up with the clamping set screw [C].
5.
Loosen the set screw [F] to zero dial under index, and then rotate the knob
[G] as required for alignment. Adjust the knob [G] vertically to allow the
spring to be clamped in a free position, neither stretched nor compressed.
6.
Tighten the set screw [F] and replace the dust cap [A].