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praezis last won the day on September 29 2018

praezis had the most liked content!

About praezis

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  1. praezis

    ANOTHER mind boggling escapement issue!

    Did you test end shake of the pallet arbor? If it is very slightly clamped by the cock, you will get what you described. A free pallet fork shall fall from one side to the other by its own weight if you turn the movement. Best tested without balance wheel and esc wheel. Frank
  2. All correct, and I admire your knowledge, but why make the matter over complicated? Here we have a coil without iron core and a low frequency of 50 or 60 Hz. You will find no relevant difference between AC or DC resistance... Frank
  3. praezis

    Boley staking set

    You are right, I missed "stumps". Frank
  4. praezis

    Boley staking set

    They used 4.7 mm like all the others...
  5. Hello Andy, this kind of circuit was factory mounted in the German made Praezima watchmakers lathe. And users kept complaining about collapsing speed under load. As I use this lathe, too, I changed the electronics per your first schematic. Now I am fully satisfied as mentioned above. You yourself posted a suitable circuit, why not stick to it? Frank
  6. The device in the video will not compensate torque when load is applied, I am afraid. Speed will slow down - different from the circuit in the above schematic. Frank
  7. On my lathe motor I use a circuit (DIY) very similar to the schematic above. Works like a charm from zero to nearly full speed, and, the best, full torque compensation esp. in low speeds. The foot pedal I use for on/off switching only. Frank
  8. praezis

    Poising with Collet Attached

    Maybe you misunderstood. E.g. a pair of 0.02 mm thick washers will change the rate by about 40 s/d. @ John: You are not aware that all these nice methods like dynamic poising are based on science and research done before 1900 ? Frank
  9. praezis

    Poising with Collet Attached

    Not really, rather in the wrong books. Effect of imbalanced balance wheels in different positions is known and published for more than 120 years (Lossier, Saunier, Grossmann etc.) Frank
  10. I rarely see Breguet coils that were not distorted... You must twist opposite of the highest point, using 2 tweezers: there is a good chance that A is the right place. The stud should not go much lower (maybe a bit) else it may touch the spring "dial up". The coil in the regulator pins area must be concentric, looks different here. I also suspect, the whole curve after the knee is a bit too far outwards. Frank
  11. praezis

    Timing and Lift Angle!!

    @John your picture shows even more: If you try to poise at >220 deg, you will make the error worse, as the effect of poise error is inverted there. @diamondslayer There is no danger at all using 52 lift angle with poising: if the real L.A. is e.g. 42 (pocket watch, chronograph etc), you will poise at a lower amplitude than expected. This just amplifies the visible rate differences in vertcal posirions! Frank
  12. praezis

    Loose roller on new balance staff

    If you need another opinion: hole closng with a domed punch (no hole) works. Just apply a light tap. Another method: a light tap in the middle exactly like tightening loose cannon pinions . Both only if its really tolerances, not a wrong, wobbling roller. Frank NB. I would not apply above methods on a hard steel roller.
  13. Soft soldering is the way this work is done on enamel dials. But: You have to heat the whole dial equally, usually with an alcohol lamp from below. Then there is no danger for the dial. Don't use brass wire for the post but copper wire. Frank
  14. Round mineral glasses are available in all sizes for little money. Thickness starts at 0.8mm afaik. They are glued in or pressed using a gasket. Window must have 90 deg edges. A too thin back can be an issue, test before cutting! Frank
  15. praezis

    Alloy vs Steel

    There is little danger to get a Nivaflex spring, as their price is a multiple of the stainless ones, so wholesalers will order the cheaper springs. Frank