Best option for grounding battery cable to frame

What is the simplest way to run a new aux battery ground cable to the frame? I'm using #2 AWG cable with copper lugs. Would a large self tapping screw work?

This is for an auxiliary battery in the bed of my truck, not the primary starting battery. Thanks in advance.

 

I always bolt it to and existing bolt.

 

I would drill a hole, clean both front and backsides of any paint, use a bolt with a nut and a star washer against the frame on the backside and lug against the frame on front.

 

This. ^^^

I always use copper bolts, nuts and washers also. A little locktight is also good.

 

Sounds cool, If it is going to be hooked up to main battery, why not tie into main battery ground wire?

 

It's a separate battery located in the rear of the vehicle. Frame is common ground.

 

Thanks. Drilling a hole it is then. I'll have to go find a cobalt drill bit to do the work.

 

On my rig, there is a factory ground at the rear of the truck. Look at the frame behind the drivers side rear wheel. I just hooked my battery up to it yesterday.

 

Why would you drill a new hole when there are plenty of bolts that you can use instead of wasting time and money?

 

I made the thread before I inspected the frame. So it was from a theoretical point of view. As it turns out, there is a 3/8 hole on the passenger side near the wheel well that's perfect for my application.