It’s confusing I know - because nobody gives you the sizes of this stuff and it’s not available as one big matched set. Basically, your going to look at the worn hole & see what side is worn or oblong. In theory, every hole that needs to be bushed is oblong, because wear only takes place at the point force is exerted on the pinion when it is under load.
Then, you get a little file, I like diamond files, & try to file the hole as symmetrical as you can. You are filing another oblong lobe on the opposite of the side worn. The size of the file doesn’t matter per se, as long as it fits in the hole.
Once that’s done, that will help the cutting broach cut a new hole true center of the previous worn hole. Basically, you are trying to cut a hole just under the size of the kwm reamer you will be using to cut the bushing hole. Most likely, the size you will need is a #3 KWM reamer, which is 2.7mm (~ 0.11”). So you want a cutting broach set that starts at a little less than that width & goes a little higher.
IMO, you will also need a micrometer. You need to measure the broach so you know about where to stop cutting on the broach. You need to measure the pinion as well when selecting a bearing. It comes in very handy when you don’t have an exact fit bearing. You can take your measurement of the pinion & broach the center hole of a smaller bearing to make it fit.
So, you want to cut a hole with the broach to about 0.10” if your using a #3 reamer & bearing. Then, you make the final cut to that hole with the #3 reamer. Then, you should have a perfect 2.7mm hole to press your bearing in. Press it from inside the plate with the oil cup facing out. It’s important to keep the reamer & broaches 90° from the plates when cutting, or you will end up with a hole that is cock eyed.
If you did everything perfect you will have a perfectly flush bearing centered perfectly. Generally, when selecting a pre-made bearing, you pick the next bigger size compared to the pinion measurement. If the bearing is too tight, you can broach the inside of that bigger as well.
In theory a set of smoothing broaches comes in handy if you are cutting the inside of a bearing bigger with a cutting broach. You should go over it after with a smoothing broach to smooth out what you cut. They also come in handy to measure the inner diameter of small holes. Sizes should be similar to the cutting broaches.
I would say you only need to put a bearing in a hole that is worn oblong. If the hole appears to be perfectly round, it’s likely not worn to a significant degree. You can also check it by putting the pinion in the hole & see how far it leans, somewhere around 5° or so is good. If it leans significantly more the hole may need a bushing, but some clocks came with more clearance than others. Don’t bush the hole too tight or you will have problems, better a little too loose than too tight.
