I recently buildt QRP-Lab's awesome QCX CW Transceiver kit.
I also ordered the official QCX case for the transceiver which is manufactured by BaMaTech.
BaMaTech also offers what they call a "QCX button extension kit" for the case, which exposes the microswitch which can be used as a buildt-in emergency straight key.
The so called "kit" comes without any instructions and just adds one set of the button parts that come with the kit for the select and exit button. So figuring out how to include it neatly involved a little fiddling.
Measuring the distances of the pot, buttons, encoder and microswitch revealed, that they are all placed 19mm apart. The volume knob is also spaced 19mm from the cases left side. The key button can be placed another 19mm from the exit button which is the same as placing it 19mm form the right side of the case. I spaced it 13mm from the lower edge of the case, which is a little higher, but seemed to be the best place to actuate the microswith lever.
So I went ahead and but some painters tape on the cased top shell to protect the sticker during drilling. I then marked the spot for my 10mm hole 13mm from the lower edge and 19mm from the right. I then put the shell on a pice of wood and centerpunched the hole's position. Using a 3mm drill, I carefully drilled a pilot hole and a 10mm hole with a 10mm drill afterwards. I cleaned up the hole from both sides with a countersink bit.
Since the micro switch is significantly higher than the other buttons, both parts, the aluminium chassis mounting and the plastic plunger are too long. I put the aluminium chassis mounting in place and mounted it with its nut to mark the position for cutting the aluminium chassis mounting flush with the nut. I removed the aluminium part from the case to cut it in a vise with a hack saw and cleaning it up using a file.
Cutting the plunger was easy. I used the hack saw to cut off the shorter part which sticks out from the rim.
Afterwards everything was ready to be mounted in the case. I put some painters tape on the three plungers to prevent them from falling out while I was closing the case.