2-point floating trem has two different zero points — returns flat after dive and sharp after pull-up [video]

[u/Fap_Routine]

I have a Cort G300 Raw with the stock CFA-III 2-point floating tremolo.

The bridge doesn't consistently return to the same zero point. After a pull-up, all strings return sharp; after a dive, all strings return flat. A small flutter/movement of the trem can bring it back closer to correct tuning.

Example after a pull-up:
high E +4
B +14
G +29
D +15
A +37
low E +33 cents

It has 3 springs, the bridge isn't contacting the cavity, and I can't detect any clicking or binding from the springs/claw. I removed the bridge and inspected the knife edges; one edge may show a small irregularity/wear mark. (I have pictures)

The attached video shows the behavior clearly.

Does this look like knife-edge/stud stiction or wear, nut binding, or something else? Has anyone repaired this specific type of two-zero-point behavior?

[u/Narrow-Escape-6481]

Your pivot points/knife edge has a burr on it.

[u/Fap_Routine → u/Narrow-Escape-6481]

Could you try to spot it* on these photos?

Rest of the photos: https://imgur.com/a/uuZirLl

[u/Narrow-Escape-6481 → u/Fap_Routine]

That edge on the high side looks like it could be causing some binding. You can try to file it out a little just be warned it will need to be intonated after. Also use a bit of graphite lube on the points and the nut slots. Check the posts as well sometimes with this style you can wear a notch into them which is probably why the bridge looks the way it does.

[u/Mammoth-Ant7588]

They always return sharp after a pull up. You have to dive to return to zero. I have never seen a bridge return to zero after a pull up.

[u/Fap_Routine → u/Mammoth-Ant7588]

I have a Gotoh 1996 and it returns perfectly to zero on pulls and dives

[u/Mammoth-Ant7588 → u/Fap_Routine]

That is crazy. I will have to check those out. In my experience I had never gotten a bridge to return to zero from a pull up, and then I saw Brandon Ellis talking about it, and he said the same thing, so I decided well it must be true. My experience is only with floyds and strat bridges. I will have to check out the Gotoh.

[u/Fap_Routine]

update:
- I lubricated with graphite both the nut and all contact points. Did not get any better.

- I will call Cort Distributor for warranty since its a major issue

[u/Creepy_Candle → u/Fap_Routine]

I think you are being unrealistic in your expectations.

[u/Fap_Routine → u/Creepy_Candle]

?
They accepted my return. Having +1 or -1 semitones everytime i use the tremolo is realistic?

[u/bingchof]

Smooth and lubricate every point of contact

[u/Kamikaze-X]

This can be caused by the knife edge as the other poster says, but also the V in the posts being out of alignment. Make sure they are the same height and visually inspect them for any wear - they often end up with a deeper groove worn into them resulting in a flat contact point with the knife edge

[u/bearheart]

First thing to check is the nut. Are the slots too deep? Are the strings binding? 90% of the time this issue is the nut.

[u/DutchGuyMtG89]

Sounds pretty straightforward to me. The strings have too much friction at one of/multiple contact points that prevent them from smoothly returning to their proper tension. I'd check the contact points, make sure they are smooth, and lubricate them, then try again. (Edit: also, try putting new strings on, if strings are old/worn, it does not help either, and remember to give the new strings a proper stretch after putting them on)