The proven pivot polisher for the matchmaker.
The Pivofix pivot polisher Instrument is the modern tool for pivot polishing and rounding of the wheel- and balance straight pivots to a maximum of completeness.
It will be an irreplaceable helper to you in the repair of all watches and small clocks. You will recognize its advantage fully when you have become experienced with it.
The usage of this instrument is easy, however please read the following manual.
About pivots and pivot polishing
The pivots of drives and shafts of a watch make high demands in several aspects. So, for example, the surface has to approach as closely as possible a perfect finish; its roughness therefore has to be small as possible. Next to the surface smoothness, the geometric accuracy plays a significant role: the pivots should have circular cross sections and be cylindrical. Deviations from the attempted ideal form have, particularly for the balance staff, negative effects on the accuracy of the watch. Finally, jigh demands are made on the dimensional accuracy. The allowable tolerances are of the order of microns.
It is known to the watch maker how hard it is to fulfill these demands. The highest requirements are made on his technical abilities. With the methods available until now, pivot polisher shovel and hand-held file, it was not possible to fulfill today’s requirements regarding accuracy and surface precision. Even more difficult, today’s pivots and staffs are frequently so hard that they cannot easily be polished successfully with a pivot file and burnisher.
The Pivofix instrument is designed to fulfill the requirements that are made today on pivot work. Its strength and precision guarantee repeatable pivot adjustments, and the silicon carbide disk with its special graining, generates a perfect surface. With Pivofix one can polisher both straight and conical pivots. The polishing of pivot shoulders is done at the same time.
What’s important is essentially the fact that success and quality of the work does not depend on some random chances or only on the skillfulness of the watchmaker. Pivot breakage has essentially been eliminated. Precision and repeatability in dimension, form and surface can be reproduced at any time.
General Description of the Pivofix
The instrument is shipped completely calibrated and ready to use. If the instrument requires adjustment, please do so only after you have become well acquainted with the Pivofix. Use of force, as with every precision instrument, is harmful, and compromises the ability to perform. Be especially careful with the silicon carbide disk, since its special properties (high degree of hardness and brittleness) also bring with them the susceptibility to impacts and acceleration. However, the high degree of hardness is also the reason why one can work on even the hardest pivots. After long use, the silicon carbide disk no longer cuts well, it has to be sent to the manufacturer for overhaul. But if you must do so, it is important not to separate the disk from the arbor.
Cast iron main housing (1) and the jacot drum are one piece. Opposite the jacot drum sits the tailstock, which is adjustable in height. The movable tailstock runner(4) is housed within the tailstock. The included dead center can be moved inside the through-drilled tailstock and locked in place via the knurled screw (6). On the tailstock runner is mounted the drive roller along with the drive pin.
The vertical location of the tailstock can be adjusted on the spindle (8) with the included wrench. Left motion of the wrench = tailstock lower, right motion = tailstock higher. The adjusting screw (9) mounted on the left side of the tailstock allows for a horizontal movement of the tailstock runner with the locked-down female centers. With grip (10) it is possible to move the complete tailstock runner towards the left and lock it in that location by rotating upwards the distance semicircle. The adjusting screw (9) supports itself then against the distance semicircle (11) via the pressure of spring (12).
Mounted on the left side of the main housing, the knurled knob is used to move the tappet roll during the rounding. In this case, movement goes from the knurled button across the drive shaft contained within the main housing via pulley of the belt (14) and [on to] the tappet roll (7). The pivot to be rounded is held on one side by the female center, on the other by the jacot drum (15). The jacot drum is mounted in a way that it can be rotated. A number of different holes allow for the insertion of the pivots. During rounding, the drive belt (33) is taken off the belt pulley (17). During pivot polishing of especially large wheels, the round segment, amongst other things, can be in the way. It can then be removed, in which case a right angled screw driver would be helpful.
The jacot drum (16) has a number of V-shaped notches, into which the to-be-rolled pivots are placed. (A table to identify the correct notch for a particular pivot diameter is located directly below the jacot drum..) The engaging of the brooch (16) happens as a result of the spring pressure onto the latch (18). The latch is attached to the drum support via the eccentric tappet screw (19) and the locknut (20).
Each unit is accompanied by two wheels (21) with silicon carbide discs. One wheel for conical pivots and one for pivots. The wheels are easily interchangeable. They are attached to the main housing with a shaft and secured with screw (23). The correct location of the wheel is guaranteed if the shaft is fully inserted and the screw tightened. The felt wiper, which is attached to the wheel, is lubricated (with an olive oil / petroleum mixture) and thus provides constant lubrication of the silicon carbide disc.
By adjusting the height of the wheel, the silicon carbide disc is moved up or down, and is thus adjusted to the dial indicator of the pivot to be polished. The adjustment of height can be performed via the micro spindle (25) by moving the levers (26). (Left turn = wheel with silicon carbide disk goes down, pivots become thinner). If the travel of the lever (26) is not sufficient to grab the or to pivot polisher it to the required dimensions, then you loosen the lever with a left turn, swing it towards the right, tighten it back down in this position with a right turn and start again with a left swing. During pivot polishing, you put a little pressure with your left index finger onto the grip (27), and after finishing the work the wheel is flipped up.
The drive of the silicon carbide disc and tappet roll is routed via the crank (28), belt pulley (17), drive belt (33) onto the shaft located in the main housing and from here via the belt(14) onto the tappet roll. The special dial indicator(29) allows it to read directly the reduction in pivot diameter. When working without the dial indicator, that amount can be read off the scale located on the micro spindle.
Servicing the Instrument
The Pivofix Instrument requires no special efforts with regard to servicing etc. Like every machine, you should oil the movable parts occasionally, such as tailstock runner, stick shaft, female centers, crank, the shaft located in the main housing, as well as the spindle within the wheel. Soak the felt wiper regularly with an olive oil – petroleum mixture, which you will keep in a small bottle. Female centers and notches of the jacot drum should always be cleaned immediately after usage. During pivot polishing, do not forget to add a bit of oil to the the female centers. You thus conserve the female centers as well as the main shaft. If problems should arise, the manufacturer is always there for you. Please contact them before you make any changes.
Pivot polishing with the Pivofix utilizes a different approach than working with a pivot shovel or a pivot polisher file. Because of the non harmonically coupled rotation of the silicon carbide disk and the work piece, one achieves a circular pivot cross section.
The pivot polisher achieves the top most precision and perfection. It is suggested that you run several test runs with the instrument, after studying the manual. Also, pivot polishing and manipulation can be practiced with old shafts and wheels. Be assured, for the actual pivot polishing, you will only need a fraction of the time required to read the manual.
The following steps describes the polishing of straight pivots. For polishing of conical balance-straight pivots, disregard points 5, 11, 13, and 14, or adjust them according to the pivot shape.
The choice of V-notches on the jacot drum (16) requires no special care, since larger dial indicator pivots can easily be worked on [when placed] in smaller notches. This may even be advisable, to avoid damaging of the jacot drum. Too large a bearing notch is absolutely to be avoided, since in this case the jacot drum would definitely be damaged by the silicon carbide disc.
1 Measure the diameter of the to-be-rolled in the usual way, and
2 Select the appropriate notch on the jacot drum (16).
3 Select the appropriate tailstock runner (5) including ( protectors that correspond to the counter and ..
4 Place them, after loosening the screw (6), into the tailstock runner(4).
5 Insert the wheel for straight pivots into the instrument using the stick shaft (22). Secure the shaft with the screw (23).
6 Insert, while the wheel is flipped down, the dial indicator until its needle registers. Tighten the dial indicator securely, and flip back the wheel.
7 Hold the work piece (wheel or balance wheel) in your right hand with tweezers and insert the pivot into the female center.
8 Push the female center with your left hand forward or backwards, so that the drive pin can securely grip the wheel.
9 Screw down the knurled screw (6). This sets the position of the female center inside the tailstock runner.
10 Turn the adjusting screw (9) until the tailstock runner with its female center has moved the wheel so far forward that the to-be-pivot polished rests in the notch of the jacot drum .
11 Be sure that the moving surface of the shaft not yet touches the front side of the jacot drum (keep about 1 to 1/3 mm distance depending on the length of the pivot).
12 Hold the wheel with the knob (27) and place the silicon carbide disc onto the pivot. (If the wheel can not be moved downward far enough, you have to turn the micro spindle (25), located on the lever (26), leftward [counter clockwise].
13 Move the tailstock runner forward by turning the adjusting screw (9) until the side of the shaft touches completely the front side of the silicon carbide disc.
14 Turn the adjusting screw now back a bit. This is to avoid the shaft applying pressure the silicon carbide disc already at the start of the pivot polishing procedure.
15 Check that the shaft is horizontal. If it is not, adjust the height of the tailstock with a wrench on the spindle (8). This control is important, since a tilted shaft would produce a cone-shaped pivot.
16 Move the lever (26) to the right until the needle of the dial indicator comes to a stop. At this moment [point], the silicon carbide disc just barely touches the . For safety you could turn farther by 0.01 to 0.02mm.
17 Before you now move the crank (28), turn the tappet roll such that the take-along point [“tappet point”?] touches the arm of the wheel or balance wheel. This avoids grinding a flat surface on the pivot.
18 Engage the drive belt (33) and turn the crank (28) “against yourself” [lit.]. At the same time, turn the lever to the left with your left thumb and put slight pressure onto the knob (27) with your left index finger. The lever movement has to be done very slowly. Turn the adjusting screw (9) during the pivot polishing so that the polishing wheel completely touches the shaft.
The leftward movement of the lever (26) lowers the wheel assembly with the silicon carbide disc. The downward movement can be watched on the dial indicator. When working without the dial indicator, the start of pivot polishing announces itself with a grinding sound. The amount by which the pivot is reduced can be read on the dial indicator or, when the wheel is flipped up, on the scale of the micro spindle.
19 Turn the adjusting screw (9) backwards a bit. The work piece is now no longer pushed against the silicon carbide disc.
20 Take off the drive belt (33) from the disc (34) and flip the wheel back.
21 Hold the work piece with your right hand using tweezers and
22 Pull back the tailstock runner via grip (10).
23 Check the modified pivot for dimensional accuracy and surface quality. If the pivot does not yet fulfill the requirements, you can further polish it without concern.
The rounding of pivots
The rounding is done in the typical fashion with a round file. Please follow the known safety rules with regard to the form and grip of the file. Don't forget to lightly oil the file.
1 Take the drive belt (33) off the pulley (34) and flip the wheel backwards
2 Position the respective hole opposite the female center (5) by simply turning the round segment (15).
3 Pull the tailstock runner backwards via grip (10) and turn the distance disc (11) upwards. The distance disc thus positions itself in front of the adjusting screw (9), and the tailstock runner with female center remains in this position.
4 Loosen the screw (6).
5 Position the work piece (balance wheel) with the to-be-rounded pivot into the hole of the round segment with your right hand using tweezers, and at the same time
6 push the female center forward with your left hand.
7 Adjust the [strength of the] engagement of the drive pin with the adjusting screw (9) and
8 tighten the knurled screw (6).
9 Move the knurled knob (13) back and forth with your flat left hand. Using a pivot file, the right hand now rounds the pivot in the usual fashion.
10 Hold on to the work piece with your right hand using tweezers, and pull the tailstock runner backwards with your left hand using the grip (10).
11 Verify the condition of the pivot.
Adjusting the jacot drum
a) If, when viewing the work piece from above, one finds that female center (5), work piece, and V-notch are not aligned, this mistake can easily be remedied.
Loosen the locknut (20), and move the eccentric tappet screw (19) until the notch is in the right position. To check, use the included centering. When everything is in the correct position, re-tighten the locknut.
b) If you find that the silicon carbide disc does not engage the exactly above the center of the shaft, you can correct this mistake in the following way:
Loosen the two binding screws (30) and (31). Move the jacot drum into the correct position and re-tighten the two screws.
c) For straight pivots, the front side of the silicon carbide disk and the front side of the jacot drum have to be parallel. If this is not the case, loosen the two binding screws (30) and (31) and move the jacot drum back and forth by respective turning of the adjusting screw (32). Then check the correct position of the jacot drum as described under a) and b), and then re-tighten the two clamping screws.
While the correct position of the silicon carbide disc for straight pivots is described in c), for conical pivots the silicon carbide disc extends over the front face of the jacot drum by about 0.2mm. This is required to work on balance staff pivots.
For polishing of pivot shoulders, it is reasonable to also let the silicon carbide disc for straight pivots extend over the front side of the jacot drum by about 0.05mm. This adjustment is done as described under c). But do not forget to bring the silicon carbide disc back to its original position. If you do forget, difficulties will develop later.
With Pivofix, you can also polish straight sections of balance wheel staffs in the same way as pivots.