Some disassembly required
A typical cleaning and oiling process includes checking and restoring pivots and bushings. This is covered on many websites and is not covered here for that reason. These images are of the other issues found in a typical repair.
Here is a picture of a movement that was so dirty I had to clean it to be able to view any necessary repairs.. Here it is nice and clean and I am sure if I oiled it it would run just fine. This is the point where some clock repair people put the movement back in the case and consider the clock repaired.............
The following images show some of the other reasons why a process known as the "Dunkan' Swish" (immersion of the intact movement in the ultrasonic) method of cleaning and oiling is unacceptable.
Take a closer look and the ratchet teeth. As you wind up the spring these teeth act against a short piece of brass called a "pawl", the teeth lift and drop the pawl and that is the clicking sound you hear when winding a clock. The pawl engages against the ratchet teeth locking the power of the spring as stored energy. If the pawl does not engage deep in the ratchet teeth the stored power may be unleashed back to the hand winding the clock (possibly your hand).
On the right image you can see bent and worn teeth. Left alone these would eventually release the power of the spring back to the key , it can be painful !
The wheel assembly has to be taken apart. This requires a little lathe work as the arbor (the steel shaft) and wheel boss are either press fit or soldered together with the wheel and washer combination being riveted to the boss.
A new ratchet wheel can easily be made or purchased. The old ratchet wheel can be turned off or removed, the new part is fitted, the wheel and washer riveted back on the boss.
It is not at all unusual to find bad repairs along the way. Sometimes they are better left alone and sometimes they are easily fixed. Here is a fan soldered to its arbor. Besides being an ugly repair, rust from flux etc it is actually wrong. The fan should fit the arbor fairly snug but be loose enough to rotate so as to reduce the transfer of kinetic energy to the arbor when the strike locking lever suddenly stops the strike train.
Here is an image of a Lantern pinion. The brass hubs hold steel pins in place, the pins engage the teeth of the wheel and drive the clock. You can see here the wear on the pins.
The hubs are seperated, the pins are just held loosely between the hubs, they are easily replaced and the hub moved back into position..
So here is a picture of the restored movement.
It looks no different to the first image.
The difference is that the restored movement will run for many years, the other would have run but for how long?
Clock movements have to be disassembled otherwise the typical problems shown cannot be addressed. The problems shown here were all on one clock and not at all unusual.
Your clock may "look" repaired, it may run a while but it may not have been repaired at all.