2-Dial Scott - pot metal and broken dial string.

[David C. Poland]

One of the dials of my 1931 Scott 2-dial was binding. In trying to determine the nature of the problem, I broke the dial string. Pot metal deterioration caused it to bind tight. I dismounted the dial assembly, and managed to separate the dial strip casting from the mounting bracket. I used a small flat file to reduce the the thickness of pot metal bracket that cradles the pot metal dial cylinder. I regained enough clearance for the dial to rotate freely again, and then used a bit of lithium lube. And I also dribbled some Super Glue into some pot metal cracks to try to stabilize both castings. 

Then I spent 2 hours figuring out the technique to restring the assembly. The problem was how to tension the dial string while tightening the last set screw. My break through was to notice the subtle flat spots on the 2 brass pieces on which  the dial string winds. Those flat spots allow use of an open end wrench. Having 3 hands would have helped.

The components of the right and left dial assembly are identical, but the tension spring locations differ.  Carefully note how each end of the old dial string is routed and attached to the brass winders on the shaft,  Remove the old broken dial string and measure the length of the old piece(s). I started with a new dial string about 2 inches longer than the old one. Remove the front brass winder and remove the shaft from the bracket in order to clean and polish the shaft. Reinstall the shaft in the mounting bracket. Tighten the set screw of the rear brass winder, but leave the front brass winder set screw loose. Install the knob on the shaft.

 Secure dial string on the  rear brass winder (like the old string was). Secure the end of the string with a tiny dab of super glue in the slot. Trim the excess string.  **Caution - avoid glueing the brass winder to the bracket !!**  Wind almost 2 revolutions of string on that rear brass winder. Rotate the dial to the high end of the dial. Start to route the string onto the dial strip casting. The tension spring goes in the front most position of the dial strip casting.  Keep some tension on the string while turning the shaft to the low end of the dial until you reach the stop, winding string onto the rear brass winder. Be sure the string engages the little pulley and lays in the groves of the brass winder, without running off the end of the brass winder when the dial is fully rotated. .....  The next part is tricky and may require several attempts.

Now finish routing the dial string around the dial strip casting to the front brass winder. Form a knot and loop around the front brass winder, but keep the knot loose until you determine the proper position for the knot. The set screw is still loose at this time.  Hold the knob steady and rotate the brass winder on the shaft with your finger so as to have about 2 revolutions or less of string on the front winder and no slack on the dial string. Be sure the string also engages the little pulley. You may have to play with the position of this knot so as to have less than 2 revolutions of string on the front winder and no slack in the dial string. Push the brass winder away from the bracket, before you secure the end of the dial string with a small drop of super glue in the slot, - being careful not to glue the brass winder or the shaft to the bracket. Allow a minute for the glue to set. Push the brass winder back against the bracket.

To tension the dial string, use an open ended wrench to hold the front brass fitting still, and use the knob to rotate the shaft against the wrench. Watch the tension spring flex maybe 1/4 inch as you turn the knob tighter. Then with one hand, hold both the knob on the shaft and the front brass winder, ... and with the other hand tighten the set screw of the front brass winder. Operate the dial to both extremes to gage how well it turns, and repeat the tension procedure as needed till you get it right.

-Dave Poland