The information below is intended for beginners.
A lot of woodworkers find it difficult to work with tiny brass screws, such as the ones used for decorative purposes on woodworking projects. It's very easy to break them off, waste them, and then have to figure out how to get them out of the hole where they are broken. Although I'm a beginner woodworker, I recently used them on my box for the box swap (you can read all about it here if you like ), and I didn't have any problem with them, so I'd like to share how to work with them successfully. My woodworking skills are very beginner, but I'm a brass screw wizard!
Brass has been around for thousands of years. It's an alloy of zinc and copper in varying proportions depending on its use. We use it because it looks a bit like gold although it's cheaper than gold, it doesn't tarnish easily and also has some germicidal properties. It has a low melting point and is easy to cast.
Here's a picture of #2 brass screws with a couple of things next to them for scale.
1. Pilot Holes
The reason why brass screws break off easily is not because they are small but because they are brass, and brass is very soft. So if you are going to use brass screws, you must first drill a pilot hole. You have to drill not just any pilot hole but one that is the right size. There are lots of charts around for determining pilot hole size. Here, here, and I like this one the best. Interestingly enough, the charts are not all the same--different people advise different things. I don't use a chart. I hold up the screw, any wood screw, to the light with a drill bit right in front of it. If I can see only the screw threads--the complete screw threads but not the body of the screw--it's the right size. Except in the case of brass screws, for which you need 1/64 bigger than you think you do. Remember, these screws are not holding up a house, the are just affixing some tiny decorative thing to a woodworking project. They don't have to be dead tight in the wood, just tight enough to hold on to something equally tiny.
I was using #2 screws, so using my method holding it up to the light, that requires a 1/16 drill bit. But with that size pilot hole, you will break off the screw. So go 1/64 bigger. That's a 5/64 size drill bit. That's the size you need to get the screw into the hole. BTW, drill bits that slender are fragile so tread slowly and carefully. Otherwise SNAP there goes your drill bit. Here are 1/16 and 5/64 drill bits.
Some people suggest screwing in a steel screw first, and then using the brass screw. I haven't tried that, so I can't speak for its efficiency.
2. Prepping the Hole and the Screw:
Why prep the hole and the screw, you may be asking. Because you're drilling a pilot hole that is slightly too big for the screw to hold. I put a tiny drop of all-purpose glue like this in the hole before putting the screw there. If you want, use a toothpick to get the glue down in the hole otherwise the screw will take it down with the threads.
I also used a little beeswax on the screw threads. I put just a tiny dab of it on a scrap block next to where I was working, and just touched the tip of the screw into it before starting. This really helps you getting the screw in without breaking it. Don't use soap--it can stain the wood.
3. Screwing in the Screw:
You like a power drill? Forget about it. You won't run it on a brass screw for a nanosecond before breaking off the screw. Too much torque. You need an old-fashioned screwdriver with exactly the right head size. Not too big and not too small. My #2 screws had a slot drive. See different screw drives here. So for that drive you need a screwdriver the fills the slot from end to end nicely. Why? Because if the screwdriver is too big, it will mash up the screw head. If the screwdriver is too small it will bugger up the screw head. Why? because these screws are brass and brass is soft. There is no margin for error here. And no second chances. If you mess up the screw head, there's no turning back.
I hold the screw head with one hand and use the screwdriver in my other hand. Turn the screw very slowly with slight pressure. The screwdriver needs to be dead straight on the screw. Lean too hard and SNAP. Lean at an angle and SNAP. Turn it too fast and SNAP. Screw it in too tight and SNAP. You get the picture. I mention this in detail because a lot of woodworkers are big and strong--and in a hurry. You cannot use the big and strong method on brass screws. You have to proceed slowly, carefully and with finesse rather than strength.
When you get close to the end of screwing the screw in place, when you know you could give it one more quarter turn, STOP. One more quarter turn and SNAP. Stop when the screw has just reached where it should be, when there is still not a lot of resistance. Maybe there's a tiny bit of wax around the screw head. Just wipe it away with a kleenex.
I practiced here in some softwood before trying it on hardwood. See the left one is broken off. That was with a 1/16 drill bit pilot hole in SPF. The one on the right is with a 5/64 pilot hole.
4. What happens if you bugger it up:
Well, the only remedy I know of is to drill it out. You can use a "screw extractor" like this, or just drill out a plug around the screw. Then of course, you have to fill the plug (maybe with a softer wood) and try again. And have a headache and delay your project.
So that's my story, and I hope it helps someone. Especially someone like me who needs all the help I can get.