So, why are there holes in truck frames?

Jus thinkin'

Road salt?

Speed holes. 

Places to mount bro-hardware and bro-accessories. 

Weight saving measure to increase MPG like it even mattered in the first place. 

Harmonic tuning.

Same reason we need bellybuttons.

On a more serious note,  my guess is that since chances are the frame cant be watertight, it is best that water be allowed in under the pretext that it has a way to drain back out.

Pete

Place to hang your ball sack. 

For you to ask why. Lol

In all honesty, for access to fasteners and such for assembly.

Now, as to why F-150s have a series of large holes on the inside of the rocker panels that they cover with tape (yes, really), I have no idea.

Some are, as mentioned, for access.  Others are artifacts of manufacturing, used for clamping, indexing, lifting, et cetera as the pieces move through assembly.  Just like some of the lumps and bosses on engine blocks.

Tom_Spangler said:

In all honesty, for access to fasteners and such for assembly.

Now, as to why F-150s have a series of large holes on the inside of the rocker panels that they cover with tape (yes, really), I have no idea.

Access for inner panel rustproofing, possibly? Tape actually works for this sort of thing, I've come across it on a number of cars that are decades old and it's holding up fine. It's not exactly cheap tape from Home Depot.

I know I've had trucks that I wish had more holes in the frame for when bolts that should be captive stop being captive.

Keith Tanner said:

Access for inner panel rustproofing, possibly? Tape actually works for this sort of thing, I've come across it on a number of cars that are decades old and it's holding up fine. It's not exactly cheap tape from Home Depot.

Have you priced tape at Home Depot?!?!

Have you priced GOOD tape?

NOHOME said:

Same reason we need bellybuttons.

Tom_Spangler said:

In all honesty, for access to fasteners and such for assembly.

If you think about it, "for use during initial assembly" and "same reason we need bellybuttons" are the same answer. I suspect in addition to fastener access that some of the holes are used to attache the frames to jigs and other devices when the truck is being put together.

Keith Tanner said:

Have you priced GOOD tape?

It was a joke.

dculberson said:

Keith Tanner said:

Have you priced GOOD tape?

It was a joke.

So was your tape apparently.

All of the above.  Because opinions are like frame holes, everybody has one.  Including me, of course.

In reply to Daylan C :

I'll have you know my tape is serious as a heart attack.

Also depends on where said holes are.  Could be for controlled crumpling during a crash. 

Not only manufacturing, but you really do not want to drill, cut, or weld a frame if you do not have to. pre-made holes make fine places to bolt parts to

Speaking of drainage holes, or the lack thereof, which German SUV has/had issues with water in the rocker panels? I mean gallons of water. There was a short video of a mechanic poking a hole and h20 rushing out for what seemed like 20-30 seconds, maybe more. 

mad_machine said:

Not only manufacturing, but you really do not want to drill, cut, or weld a frame if you do not have to. pre-made holes make fine places to bolt parts to

I've heard this many times, but have always wondered why.

stuart in mn said:

mad_machine said:

Not only manufacturing, but you really do not want to drill, cut, or weld a frame if you do not have to. pre-made holes make fine places to bolt parts to

I've heard this many times, but have always wondered why.

It's significantly cheaper to punch rhe holes in the frame blank before forming it.  It varies depending in many things but for a typical automotive frame where tolerances allow features on both veriticle and horizontal faces can be added in 1 punch.  Sometimes you would need to drill if you needed very tight tolerances or if production volume was low enough to not tool the frame blank.  Though in that situation you would likely Lazer/water jet all the holes in the flat also.

You also may be heat treating the frame which would make drilling difficult and welding potentially resulting in local weakening.