Tuning stability with tremolo bridges can be problematic and very frustrating, especially when recording. Solving these problem is not rocket science but with such a complicated mechanical system it can certainly can seem like a black art. But there is a simple way of thinking through tuning problems which might help…
First, never work with old strings. Old strings don’t stay in tune. Put new strings on your guitar. Learn how to do it properly and stretch them properly.
Now that you have fresh strings and you have tuned up, if you have problems staying in tune, ask your self which strings are going out of tune. Is it one string in particular? If so, does it go sharp or flat?
If one string goes sharp, it could be binding or catching somewhere, and that means friction. A little lubrication in the nut slots can make a world of difference. I also add a tiny amount to the top of the saddles and to the string trees (if you have any). Mineral oil, chapstick, vaseline, pencil lead, lithium grease all work well but only use the minimum amount necessary! I apply with a toothpick or needle. I also clean old lube off during every string change. For a more in depth look at lubricating your guitar, see my article “A Little Lube Goes a long Way“.
If one string goes flat, it may be slipping or stretching, which suggests stringing technique. For non-locking tuners, make sure the string has enough wraps around the tuning posts. If you have locking tuners, make sure to use the correct stringing technique and that the tuning locks are tight. Also check that the ball end is well seated in the trem block. Stretch new strings well (without tugging so hard that you damage or kink them).
If all strings are sharp or flat after trem use, now we have a situation where the bridge is not returning precisely to it’s original position. We may have to look at the knife edges and mounting posts (perhaps clean or light lube if necessary). On Floyd rose double locking systems we may also have to look at ensure the lock nut is stable and firmly attached.
But we must remember a simple fact – there is no such thing as perfect tuning stability. Friction is the cause of 95% of tuning and trem troubles. But friction is impossible to eliminate completely. The guitar is, by design, an instrument full of compromises and can never be ‘perfectly’ tuned even if our tremolo systems work as well as the laws of physics will allow. Don’t fall into the trap of chasing unobtainable perfection.