how much dammage will do to the frame if I drill holes to mount a set of horns and air tank and a compresor? I cant seem to find any place to mount exept on outside of frame rail

When you put your nerf bars and plow on didn't you have to drill some mounting holes?
Small holes in various places should not hurt anything. These frames are suppose to be stronger than the old ones. Those horns may rattle loose some rivets.
I heard a comment from someone that said the Dodge frames will crumple on impact. I am not sure if this is true or if it was for the older style Dodge or not.
Just putting that out there.

I think that www.gmupfitters.com has some general guidelines on how and where to drill holes in the frame. Some places are OK, some are not due to other holes or structural members causing weakness in the frame.

When you put your nerf bars and plow on didn't you have to drill some mounting holes?
Small holes in various places should not hurt anything. These frames are suppose to be stronger than the old ones. Those horns may rattle loose some rivets.
I heard a comment from someone that said the Dodge frames will crumple on impact. I am not sure if this is true or if it was for the older style Dodge or not.
Just putting that out there.
no holes had to be drilled for either the plow or the nerf bars. nefr bars used the cab bolts and the plow used holes allready there. the place that I want to put the horns and compresor is at the back of the cab on the outside of the frame.

In general, you should not drill holes in or near the flanges of the frame rails. Instead, drill in the center of the web (the flanges are the top and bottom of the frame rails, and the web is between the flanges). The reason is that the highest stresses typically occur in the flanges of a frame rail, and any holes in these flanges weaken them by removing material and creating stress risers. (This is not an absolute rule, as GM and other Mfgs put some holes in the flanges in various locations to attach cross members, as jig/fixturing locations, and for other reasons.)

GM makes the truck frame rails from three pieces. A hydroformed front piece with a fully boxed cross section, a roll-formed middle piece, and a rear piece with a stamped "C" cross section.

If you want to mount something on the side of the frame just behind the cab, that is the middle roll-formed piece. GM calls the middle piece "roll-formed" because of how it is made by rolling the steel through special dies giving it the cross section shape (with the flange edges rolled back inward), and bending the steel to its final shape.

To be clear, the web is this ->[ part of the frame rail, and the flanges are the flat (or flat with rolled inward edges) top and bottom parts.

Caution! Always check to see make sure there is nothing on the other side of the frame rail before drilling through! On the drivers side frame rail, in addition to some electrical wires, there are the diesel fuel send and return lines.

thanks for all replys looks like i will get the drill out.

I am doing the same thing. Going to use the INSIDE rail on d side, more stealth and noise reduction. Navigate the fuel lines and drill holes for standoff bolts. At first I thought I couln't use this area, but now I think it is the best area, as I want the 5 gallon SS tank to be accessible from the d side. Air tools, tire fills, air bags. I mounted the air horns under the air filter, pointing down, that way I can use the car horn harness for the solenoid.

Could you not build a bracket that goes all the way around the frame and clamps together that has a tang on it to bolt the accessory? Kinda like a big clamshell piece, either interlocked (hinged) on one corner and bolted on the other OR bolted on both sides.

If I mod the 05 I just bought, I really don't want to drill into the frame so I will go that route.
Just giving you options, good luck.

Happy New Year to all!

Costas
05 CC SB DA 4WD 2500HD

MasterP2, I agree with using the inside of the driver side frame rail. On my CC, SB there is plenty of open space availabe if you use standoff bolts to place your mounts off of the diesel fuel lines. Only concern is maintenance access both for what your adding and all existing components, but this is probably the best area.

Shortcutsleeping, yes you could also clamp around the frame rail to avoid drilling, but I personally would not hesitate to drill through the center of the frame rail web, or use existing holes in the frame rail web. I'm a mechanical engineer and am familiar with structural design issues, so that is why I gave input.

Happy New Year!

I've drilled my frame to put brackets for my fifth wheel, 2 years and no problems. A little tought getting the nut on the head of the bolt with the boxed in frame.

I agree, some 3/8 holes on the web is not going to be a problem, just no holes on the top and bottom of the "C". Another engineers opinion.

Just thought I'd mention, I have another 5 gallon SS tank, custom made, I will sell for $175. If anyone is interested i will post pics in the classified.

OK, for us idiots out there who didn't do enough research for drilling a frame, who drilled the top of the "C", what can we do to fix the potential stress problem?

I added/bolted a piece of angle iron for a lift pump/filter installation, 2 3/8" holes.

Am I screwed?

It's mostly in compression, don't lose any sleep. Really. These channels are overbuilt for almost everything we do, no flex at all, part of the empty rough ride problem I'd guess.

you guy's with crew cabs sure have a lot more room under there than us reg. cab people. I have no room under there at all.