I have a KMM and when resetting the carriage it immediately moves to the middle, and then works as it should. If i add pressure to the ratcheted toothed bar it can behave normally. I don't think it is an escapement issue but I'm not sure how to fix this issue.
I have linked a video demoing the issue
Hi
@tomachuck
In my experience, that symptom of carriage snapping to a fixed point on reset and then behaving *usually* means the drive line is fine but something in the rack / escapement interface isn’t staying consistently engaged across the full travel.
On a KMM the toothed rack, starwheel, and escapement dogs have to sit in a very particular relationship. “Tight tolerances” is a hobby term we use. If a little finger pressure on the rack makes it act normally, imho the pinion isn’t quite meeting the rack at the correct depth or angle on its own. In other words, not a “timing” failure so much as a mesh issue.
A few things I would look at before touching adjustments:
Rack alignment and height; dried grease or a slightly tweaked rack rail can hold it a fraction low until you nudge it. These machines only tolerate tiny deviations.
Carriage endplay / carriage bearings; if the carriage can lift even a hair, the pinion will ride shallow and skip until pressure puts it back into full engagement.
Escapement mounting screwsif they’ve relaxed, the whole unit can sit a touch too far from the rack.
Drawband tension; weak mainspring won’t always pull the pinion firmly into the rack, and the “helping finger” you describe temporarily substitutes for that force.
The fact that it works perfectly once past that point is actually encouraging!!! it says the teeth themselves are probably fine and the starwheel isn’t chewed.
Personally I’d start with a deep clean of the rack and pinion area (flush, then run it dry), check for vertical play in the carriage, and only then consider any positional adjustment of the escapement body.
When you reset the carriage, does it drop slightly at the moment it jumps to the middle? And if you very gently lift up on the left end of the carriage while typing in that problem zone, does the behavior change? Those two little tells can narrow it down fast.
KMMs are tolerant, (inasmuch as a Royal can be; I find them temperamental overall) but when the rack mesh is even a fraction off they’ll give exactly this kind of polite protest.
Ezra
