DIY "bullet" style harmonica mic!

Step 3 Drill some holes!

Now you have to drill some holes. Take a 1/8th" drill bit and drill some grill holes in the end of the PVC end cap. I laid out a nice concentric ring pattern using a compass. Now check to see if the fence post cap actually fits into the PVC endcap. If it does, you are golden. If not, then you'll have to carve out a bit of material from inside the rim of the PVC endcap. I had to remove about 1/32" all around the inside of the lip of the PVC endcap before my fence post cap would fit properly into it. You'll likely want to sand the end of the end cap after you drilled the holes. This is the business end that you are going to have in your cupped hands all the time, so you want it to me smooth and comfortable. Mine had some embossed letters on it (basically telling the brand and size) which I sanded off to make it perfectly smooth. I first sanded with 80 grit, and then smoothed it 250 grit. Look at the pics and the video from step 1 to get the idea about where to sand.

Next, drill the holes for the 1/4" guitar jack and the potentiometer (volume control) int he metal fence post cap. The hole for the guitar jack will need to be 3/8" in diameter, and the hole for the potentiometer will need to be 1/4" in diameter. So use those two drill bits, or a step drill bit to do these. Look at the picture to see how I laid these out (at angles on opposite sides of the fencepost cap).