Precise Holes in Automotive Carpet without Fraying

The gunny way.

Drilling a hole directly through carpet will cause major damage as the carpet threads wrap around the drill bit and can ruin the carpet.

I’ve read various tips for making bolt holes through automotive carpets: cut an “X”; use a soldering iron; heat a pipe; use an awl, etc.

I mounted two Halon Fire Extinguishers into may latest super secret project car that required precise mounting bracket hole locations due to tight clearances and space constraints.

Here’s how:

1. With carpet in place in the car, position accessories and brackets in desired locations.
2. Dab a touch of contrasting paint at the center of the desired hole location (white paint for black carpet) using the brackets as a template.
3. Use a punch or an awl and a hammer to mark the spot in the metal below the carpet at the center of the paint mark
4. Remove carpet section and place over piece of scrap wood.
5. Position a fired brass pistol or rifle casing over the center of the paint mark.  Open end down; primer side up.
6. Strike firmly with hammer – driving cartridge brass through the carpet and into wood underneath.
7. Remove carpet from wood.
8. Drill holes in metal floor at punch marks from Step 2, above
9. Reinstall carpet, align holes
10. Bolt brackets into place.

I used 9 mm casings for bolt holes up to 5/16″.

You can use .50 BMG casings for holes up to 1/2″.