Before installing the needles, here's a tip that can help you avoid needle the binding that causes the flooding that so often follows a fresh rebuild;

The seats have very small, nearly microscopic concentric tooling marks on the inside. Again, on a microscopic level, this makes for a very rough surface that's not conducive to having another brass part slide easily across it's surface. While there's not much we can do about the inside of the needle seats, we can do something to the needles themselves to decrease the friction as they move in and out of the seats. The seats are not polished inside, but the surface is at least consisten t, and there is no way to polish the insides to that same consistency, even with my watchmakers lathe. Please do not try. While polishing the insides of the cylindrical needle seats sounds like a great idea, it's a fruitless, messy effort that won't yield results worth the time. They can even end up sticking worse.

But what you can do that's very quick, easy & effective, is burnish the four corners of each needle. The needles are "tumble polished" after they are spit out of a manufacturing machine, and as a result they have a matt finish. This is where the friction comes from.

Coat the outside of the needle in about a finger-print's worth of oil, and take something small and highly polished and lightly rub it along the shaft on each corner very lightly. You should start to see the corner get brighter. This is burnishing the surface, and it's the same as "breaking in" the part. Try not to rub hard as that can cause tiny gouges in the surface, defeating what your trying to accomplish. All in all, this process should need more than about 4 or 5 minutes, but it can save an hour or more of aggravation later on.