Tips on precision drilling?

[Sevinzol]

1. A nail is not good for centering because it is only work hardened mild steel, not tempered. People are mentioning Center Punches. There are several types. I have 3 myself: one designed to center a mark relative to an existing hole (like a door hinge). second is a spring loaded Automatic Center Punch, and the third is just a solid old one piece Center Punch. My suggestion is use the old fashioned one piece with a (small) hammer. You'll have better control with how hard to hit. remember Aluminum is soft.

2. Use your drill press, you have one. If the bit is drifting then choke up on it (stick it as far in the chuck as you can). If the bit is wobbling then your chuck is seated crooked, you need to remove and reseat it (this can take hours). There might be a set screw inside the chuck but many are just pressure fit. consult your manual. Make sure to set your speed right. metal is not wood. Use some oil. I use 3-in-1, WD-40 is not oil its designed for rusty bolts. it is too thin to work as a cutting oil. the oil is there as a lubricant, a heat sink, and to help suspend the metal particles.

3. Make a "V" block. if you don't have a machinist vice to hold the piece solid then cut a piece of 3/4 plywood, lengthwise with the blade at a 45 degree angle, glue and screw these pieces to a third, wider piece and clamp this to the drill press platform.

4. Go slow and use the drill bit size you need. I don't recommend sneaking up on it by making a smaller hole first. because this can contribute to chatter and might mess up the roundness of the hole. DeWalt sells Pilot Point HSS drill bits.

5. When you tap. Practice on a scrap piece. Double check you have the right sized hole. If its even slightly too small you will probably break the tap by forcing it. Use oil. Turn the tap only 1/4 - 1/2 turn then back it out a 1/4 turn. This breaks the little shavings you are creating and helps prevent them from jamming up the tap. If its going right, it should feel smooth and not resist, if you have to crank it, then back it out to clear the shavings, add oil and go again. considering how thin an emitter is, you shouldn't have to do that.

... and remember we're having fun.

[Denz]

Use a milling machine.

[Silver Serpent]

1. A nail is not good for centering because it is only work hardened mild steel, not tempered. People are mentioning Center Punches. There are several types. I have 3 myself: one designed to center a mark relative to an existing hole (like a door hinge). second is a spring loaded Automatic Center Punch, and the third is just a solid old one piece Center Punch. My suggestion is use the old fashioned one piece with a (small) hammer. You'll have better control with how hard to hit. remember Aluminum is soft.

2. Use your drill press, you have one. If the bit is drifting then choke up on it (stick it as far in the chuck as you can). If the bit is wobbling then your chuck is seated crooked, you need to remove and reseat it (this can take hours). There might be a set screw inside the chuck but many are just pressure fit. consult your manual. Make sure to set your speed right. metal is not wood. Use some oil. I use 3-in-1, WD-40 is not oil its designed for rusty bolts. it is too thin to work as a cutting oil. the oil is there as a lubricant, a heat sink, and to help suspend the metal particles.

3. Make a "V" block. if you don't have a machinist vice to hold the piece solid then cut a piece of 3/4 plywood, lengthwise with the blade at a 45 degree angle, glue and screw these pieces to a third, wider piece and clamp this to the drill press platform.

4. Go slow and use the drill bit size you need. I don't recommend sneaking up on it by making a smaller hole first. because this can contribute to chatter and might mess up the roundness of the hole. DeWalt sells Pilot Point HSS drill bits.

5. When you tap. Practice on a scrap piece. Double check you have the right sized hole. If its even slightly too small you will probably break the tap by forcing it. Use oil. Turn the tap only 1/4 - 1/2 turn then back it out a 1/4 turn. This breaks the little shavings you are creating and helps prevent them from jamming up the tap. If its going right, it should feel smooth and not resist, if you have to crank it, then back it out to clear the shavings, add oil and go again. considering how thin an emitter is, you shouldn't have to do that.

... and remember we're having fun.

I agree with all these tips except #4. Pilot holes work well for me, and I recommend starting with smaller bits and working up to the right size. Those drill bits look like a good option in either case.