I've been wanting to make this mod for some time now. Been eyeballing other peoples designs, and finally felt confident to do it. I made it out of some random tool in my garage. It only took about an hour and $4.00 for a 200omh resistor and a 3amp switch.
This is the atty connector I ripped out of a dead 510 battery. I had to use a pipe cutter to do it.

This is the inside of the tool I gutted for the passthru. It has the switch mounted in this picture, but nothing is wired yet.

Then I got excited and forgot to take pictures during the rest of the process.
I put the 220omh resistor between the data lines so that it will be in "charge mode" when connected to a computer. I was a little worried about things fitting, but it all just barely did.
This is the result:

Yes, that's tape at the bottom! I still plan on making some changes to it. And I plan on spraying it black sometime but that will require a disassembly and I'm just happy it works for now.
This is the atty connector I ripped out of a dead 510 battery. I had to use a pipe cutter to do it.

This is the inside of the tool I gutted for the passthru. It has the switch mounted in this picture, but nothing is wired yet.

Then I got excited and forgot to take pictures during the rest of the process.
This is the result:

Yes, that's tape at the bottom! I still plan on making some changes to it. And I plan on spraying it black sometime but that will require a disassembly and I'm just happy it works for now.