You'll need machine screws in order to secure an Adafruit Feather to the case. In this example, we're using M2.5 nylon screws with nuts.
Set & Align
First thing we'll need to do is set the Adafruit Feather into the case with the USB port facing the cutout. The PCB should rest over the standoffs. Position the board so the mounting holes line up with the holes in the standoffs. With the board positioned in place, hold it down using your finger and flip the case over.
Install Machine Screws
Insert a single machine screw into one of the mounting holes on the bottom of the case. If it's a M2.5 sized screw, the threading will be loose so you'll need a nut to secure the board to the case. If your using a #4-40, the threading will bite into the standoffs and mounting holes. I recommend using a screw with a chamfered head so that it can be flush with the surface of the case. The M2.5 nylon screws we offer have a beveled head, so it will slightly protrude from the bottom of the case. Once the first screw is secured, fasten it all the way. Then, insert and fasten the remaining screws into the standoffs. You can secure all four mounting holes, but you could also just secure the two nearest to the microUSB connector.
Before we fit the battery into the battery holder, we need to think about how we plan to use it. First, pick your battery size (2000mAh being the biggest that fits into the holder). You have the option to use a slide switch JST adapter or wire a slide switch to the enable and ground pins on the Adafruit Feather.
The slide switch JST adapter will allow you to cut the power from the battery. However, when you recharge the battery over microUSB, the Feather will stay powered on. You may or may not want the Feather powered on while recharging.
Connecting a slide switch to the enable and ground pins allows you to power off the Feather but still allow the the battery to recharge over microUSB. However, you'll have to use up one of the ground pins and connect directly to the enable pin – If you're using an Adafruit Feather Wing, you might find it cumbersome.
Either option, you'll have to determine which solution is best for your project.