Cal. 1861 Speedmaster Erratic Timegrapher Reading Cause

Ron_W · Jun 10, 2026

Hi, i got this 1999 Speedmaster 1861 yesterday, gave it a full wind and after wearing it 16 hours + 8 hour dial up rest, it lost just 4 seconds.
But on the Timegrapher dial up 12 sec interval i get this ;

- 39 / - 7 / -27 / + 17 / + 17 / - 41 / - 1 ?? Any idea what is happening ? looks like Shakin' Steven.

My cal 861 Speedy reads fine and has a steady straight line so i think the machine is okay.
Thanks for your thoughts !

ErichKeane · Jun 10, 2026

Thats odd, I've not seen something like that before! The frequency of that though makes me think it is something to do with the escape wheel though, since it is roughly every ~20 beats. Could possibly be a spot with sticky oil, or crap, or something?

lenndon · Jun 11, 2026

Maybe a bent escape wheel is creating slight friction at a certain point and then releasing again.

Interesting reading. It definitely shouldn't keep running like that.

padders · Jun 11, 2026

The quick answer is that it obviously needs a service.

Ron_W · Jun 11, 2026

Thanks all, and yes definitly should be cleaned and serviced.

Ron_W · Jun 19, 2026

The main issue seems to have been that the 2 holding screws on the movement / enlarger ring were loose. So there may have been some extra or double vibrations as now that it is thight again the reading is a whole lot better. I got the timing regulated to Around + 5 sec p/d while wearing it, so on the wrist it is fine for me, but the Timegrapher stills shows a fluctuation curve from fast to slower and back again, changing per two 12 sec interval timingperiods. Not like the staircase of the picture above but more fluent.

This is worse with a full wind and almost gone in the 2nd 24 hour of power reserve, but is the torque/pressure on the train (much) weaker in hour 25 trough 40 of the PR ? Beat error remains around 1 ms and amplitude is still good 240 - 260.
Can the crown be the problem and somehow not transfer the ticking correctly ?

Thanks for your thoughts !

Endshake · Jun 21, 2026

Maybe some gears are bend slightly because the mainspring once snapped or wasn‘t let down correctly.

DragonGeek007 · Jul 6, 2026

Zigzag behavior lists as knocking or overbanking in my old watch repair book. But the amplitude would be a lot higher, I’d think.
I’d wonder if either the impulse jewel or palette jewels are out of alignment. Just enough to make this weird effect. Check those.
Also, this may be something different… that your timegrapher is just not “hearing” two consecutive beats, and the effect looks like a drop like this. It’s trying to fill in the blanks. If it’s that, you may have too much oil on the palette jewels, or the escape wheel has a few spokes that are over-lubed.
Finally, the escape wheel teeth. This is pretty cyclical. Are those teeth in good shape? Is the wheel out of alignment?
My suspicion is over-oiling. But have a look at all those bits and make sure they’re not bent, loose, or chipped.

Ron_W · Jul 6, 2026

DragonGeek007
Zigzag behavior lists as knocking or overbanking in my old watch repair book. But the amplitude would be a lot higher, I’d think.
I’d wonder if either the impulse jewel or palette jewels are out of alignment. Just enough to make this weird effect. Check those.
Also, this may be something different… that your timegrapher is just not “hearing” two consecutive beats, and the effect looks like a drop like this. It’s trying to fill in the blanks. If it’s that, you may have too much oil on the palette jewels, or the escape wheel has a few spokes that are over-lubed.
Finally, the escape wheel teeth. This is pretty cyclical. Are those teeth in good shape? Is the wheel out of alignment?
My suspicion is over-oiling. But have a look at all those bits and make sure they’re not bent, loose, or chipped.

Thanks for your post ! and i have "the impulse jewel or palette jewels are out of alignment" as first suspect to start with to check out as well. But that is way out of my league so after my watchmaker gets back from his holliday he can take it on and i will update with the outcome.