Step 4: Mark & Pre-punch Holes for Jacks Before Drilling
- Make 4 marks on the long side center line, spaced out by about 3/4 of an inch.
- Make 1 mark on the middle of the center-line on the short side.
- In order to keep the drill from wandering, it's good practice to punch the holes with an automatic punch or awl.
Hint: It's a good idea to put a small piece of wood or a big rubber eraser behind the thin metal to keep it from bending.