The
Model 260

High Frequency, New Numbers

The Timex Model 260 is an 11¾ by 12¾ ligne electric watch movement featuring a high frequency balance system. It operates at a rate of 28,800 beats per hour. The rate can be checked on recorders having a setting for 28,800 beats per hour, or on some recorders using a setting for 14,400 or 21,600 beats per hour.

The Model 260 is powered by a Timex Type A energy cell which provides power for at least one year.

The Timex code number on the edge of the dial gives the catalog number, movement number and year of manufacture.

Exploded View

Model 260 · 29 Components

Ref.Component

0032Dial

1011Hour Wheel Assembly

1020Center Wheel Assembly

1022Connector, Energy Cell

1041Hour Wheel Washer

1157Third Wheel Assembly

1165Friction Washer

1169Hairspring Wedge Pin

1171Hour Hand

1172Minute Hand

1177Seconds Wheel Assembly

1178Minute Wheel Assembly

1184Sweep Second Hand

1185Dial Rest

1199Friction Pinion

1421Shunt Bridge Screw

1428Balance Bridge Screw

1487Balance Bridge Assembly

1493Index Lever Assembly

1494Index Wheel Assembly

1496Contact Spring Assembly

1502Shunt Bridge

1578Friction Spring

1579Train Wheel Bridge Assembly

1580Stem Bracket

1648Setting Stem with Crown

1716Stop Lever

1718Balance Wheel Assembly

1901Plate Assembly

Disassembly

The Caseback and Cell

1

Insert a blade into the opening on the bezel and pry the caseback off. The locating tab on the caseback is used for orientation of the back during reassembly.

2

Remove the energy cell, then lift off the movement cover. The cover is held in place by two tabs which snap into recesses in the bezel.

Note: Any energy cell with a voltage of less than 1.5 volts, or one in service in excess of one year, should be replaced. Use of an energy cell not meeting Timex specifications may cause the watch to malfunction.

Fig. 260.3 · Caseback & Cell

The Movement Cover

•

The cover and the tab which snaps into the bezel, with the movement beneath.

Fig. 260.3 · Movement Cover

Releasing the Stem

3

The stem is held in position by the stem bracket. Pull the stem out into the set position and continue to maintain a slight outward pull.

4

Place the points of a tweezer into one side of the stem bracket and push the bracket aside to release one side of the stem. Continue to pull the stem outward and use the tweezer points to release the other side. The stem will now pull free of the movement and bezel.

Fig. 260.4 · Stem Bracket

Out Through the Crystal

5

After the stem is removed, the movement can be removed through the crystal side of the bezel. Remove the crystal with a crystal seating tool and then lift the reflector ring and movement free of the bezel.

Note: Note the position of the movement locating tabs inside the bezel. Tabs should properly align in the notches of the plate when reassembling the watch.

Fig. 260.4 · Case

The Dial

6

Remove all hands. Straighten the dial tabs enough to remove the dial from the movement.

7

Turn the assembly over and lift off the dial. Lift off the hour wheel washer and hour wheel assembly.

Note: With the above parts removed, the basic movement may be replaced with a Timex reconditioned movement. The parts removed are then assembled to the reconditioned movement.

Fig. 260.5 · Figure A

The Shunt Bridge

8

Turn the movement over and remove the shunt bridge screw. Lift the screw end of the shunt bridge off its post and carefully slide the shunt bridge from the movement, noting the tab on its end which engages the plate.

9

Replace the shunt bridge screw.

Fig. 260.5 · Figure B

The Balance

10

Remove the hairspring wedge pin; do not distort either the pin or the hairspring. Note the hole in the balance bridge which permits access to the wedge pin.

11

Rotate the balance wheel carefully until the hairspring tail is free of the hairspring bracket and the regulator.

12

Note the position of the energy cell connector by sliding it out. Remove the two balance bridge screws, lift off the balance bridge assembly and carefully remove the balance wheel assembly.

Note: If the wedge pin cannot be loosened through the hole, remove the two balance bridge screws and carefully remove the balance bridge and balance wheel assembly from the movement to permit access to the wedge pin.

Fig. 260.5 · Figures C and D

Cleaning

The best way to clean the Model 260 movement is to disassemble it only to the point of removing the balance bridge and the balance wheel assembly. The movement should be placed in the watch cleaning machine, including ultrasonic baths, preferably on edge to insure proper drainage of the fluids. The movement must be immersed in two sets of rinsing fluid, and the final rinsing solution must be absolutely clean. After cleaning is completed, the movement must be thoroughly dried.

The balance wheel assembly must be cleaned separately in order to prevent damage to the balance staff points, the hairspring and the coil. Other metal parts may be cleaned in the same manner as the movement. Only standard watch cleaning solutions should be used.

Lubrication

Apply non-spreading type oil, Moebius Synt-A-Lube in the factory, to the minute pinion stud at the top face of the minute pinion; both pivots of the index lever assembly; both pivots of the index wheel assembly; both pivots of the sweep seconds wheel assembly; the back pivot of the third wheel assembly; the junction of the minute wheel with the dial ring assembly; the junction of the minute wheel with the plate assembly; the index wheel on the driving face of three teeth; and the index lever fork where it engages the impulse pin.

Front and Back Views

•

The index wheel assembly pivot, dial ring assembly, friction pinion, minute pinion and stud, index lever assembly pivot, sweep seconds wheel assembly pivot, third wheel assembly pivot, plate assembly and minute wheel through the stem bracket slot.

Fig. 260.7 · Front & Back Views

Filling the V-Conic Bearings

•

Fill the V-conic bearings three eighths to five eighths full, by depth.

Fig. 260.7 · V-Conic Bearing

Apply spreading type oil, Woods AAAA in the factory, to the friction pinion at its junction with the plate assembly, point A. Apply watch grease, Hamilton PML in the factory, to the set stem teeth and bearing surface below the teeth, prior to assembly of the stem to the watch head.

Reassembly

Refitting the Balance

•

Insert the balance wheel assembly, impulse-disc end into the V-conic bearing in the plate assembly. Assemble the balance bridge and the two balance bridge screws, being careful to assure proper engagement of the balance pivots in their respective V-conic bearings.

•

Do not tighten the balance endshake adjusting screws completely. They should be tightened only enough to hold both balance pivots securely engaged in the V-conic bearings.

•

Slide the energy cell connector into place.

Fig. 260.8 · Figure E

The Hairspring and Regulator

•

Insert the end of the hairspring into the slot in the regulator and then into the hole in the hairspring bracket by rotating the balance wheel and guiding the end of the spring. Check that the impulse pin is in the slot of the index lever, then secure the hairspring in the bracket with the wedge pin.

•

The hairspring should be levelled, centred and in light permanent contact with the inside edge of the regulator slot and the regulator tab. It must not leave those contact points at any time with the regulator within normal regulating range.

•

Adjust the level by grasping the spring as close as possible to the pinning point. To adjust centring, grasp 180° from the pinning point. To keep the spring in permanent contact with slot and tab, carefully bend the tab towards the centre of the spring.

Caution: Adjust the balance wheel assembly endshake cautiously by tightening the balance endshake adjusting screws. Do not adjust too tightly, because excess pressure can damage the pivots of the balance staff. Loosen the shunt bridge screw, slide the shunt bridge under the hairspring, and secure with the shunt bridge screw.

Fig. 260.9 · Figure F

After the basic movement has been cleaned, lubricated and assembled, reassemble in order: center wheel assembly, hour wheel assembly, hour wheel washer. Carefully orient the dial on the movement so the dial tabs engage the notches in the dial plate assembly, then, holding the dial firmly in place, turn the movement over and bend the tabs to secure the assembly. Assemble the hands at the 12 o’clock position.

The Sweep Second Hand

•

Drive the sweep second hand onto the end of the sweep second staff, being sure the hand is below the chamfer on the staff.

Fig. 260.10 · Figure G

Place the movement and dial assembly in the case, being careful to position it on the locating tab. Position the reflector ring on the dial and replace the crystal to secure the assembly. Insert the crown and stem assembly with a turning motion to assure engagement in the stem bracket. Put a fresh Timex energy cell Type A in place, positive side up, position the caseback and snap it closed. Push the crown in and the watch will start; if it does not, slight rotation may be necessary to restart the mechanism.