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Up Topic Welding Industry / General Welding Discussion / need to extend F-350 frame for hitch - question
- - By chapman14219 (*) Date 02-15-2007 19:39
I recently bought a 1994 Ford F-350 4x4 cab and chassis with a 12 foot flatbed...the 161 inch wheel base truck frame is about a foot shorter than the flat bed body & I want to put a heavy duty hitch on this I will be going to the local steel vendor and having some 12 inch long frame extensions formed and will weld them to the end of the frame to extend it.

My question is does anyone know if the Ford frame is anything other than mild steel?.....Im planning on using either stick 7018 or mig E-71T....possibly .035 ER70S-6...and fish plating the joints...on the inside of the formed channel.....then bolting the hitch on - half on the extension and half on the orig frame..........any comments ?

thanks in advance
Parent - - By darren (***) Date 02-15-2007 22:52
DO NOT WELD EXTENSIONS, bolt on as there are many legal requirements to modifying a frame, bolt on ok, weld is subject to to many requirements, if it fails you are liable for costs of the failure (like killing someone if the trailer comes away from the truck) the frame is at least t-1 and probably a proprietary alloy, have extensions bent the same as frame rail and a fish plate bent to the inside shape of the frame rail then bolt together, try and incorporate the hitch into the bolt pattern . if you are gonna weld you will need to get vehicle d.o.t. certified and some sort of welding credentials and perhaps even rt or ut inspection (depending on the state). there are guys with plenty of experience with welding frames on here they may be willing to tell you other opinions. I have welded many frames on all sorts of vehicles, trailers and equipment and do not recommend that you do so without a VERY GOOD working knowledge of the codes, requirements, and techniques of welding on motor vehicle frames.
Definitely a solvable problem just look into the regulations and codes within your area so as to protect yourself from liability.
Parent - By Molten Metal (**) Date 02-15-2007 23:09
Darren may be right.But I THINK that the frame is just mild steel.In either case,if you know how to weld good,I'd use the 7018,as it's good on alloyed steel's as well as good ol' mild steel.If you arent confident in your welding,have a qualified person do it.I have welded a zillion 5th wheel hitches to truck frames and never had a problem.But,  I' dont know all the law involved with that scinerio either.Good luck.
Parent - - By Smokey71 (*) Date 02-16-2007 00:01
I agree with darren. For as long as the vehicle is on the road, wether or not you own it or someone salvages it from a junkyard, it's welded by u and therefore you r LIABLE. I wouldn't risk it. No one likes to drill through a frame but even more so no one likes a lawsuit. You can make a zillion good welds but the only one anyone remembers is the one that breaks!
Parent - - By Molten Metal (**) Date 02-16-2007 01:35
Not being a smartass here,but,wouldnt a person be liable weather he bolted a modified section onto a frame and it broke/came loose and killed someone.Whats the difference.?Wouldnt you get sued just the same if it failed while being bolted instead of welded?Just curious.I do agree one should always err on the side of caution.
Parent - By DaveBoyer (*****) Date 02-16-2007 05:36
I used to work for Dana corp. Parrish Pressed Steel. It is likely that Your frame was made at that plant. To My recolection the frames were made from mild steel, but I left there in '91. I will try to get a material spec from a friend who ran the lab in those years and post it for You. I am pretty sure the companie's position would be no welding or modifing of the frame, but We all know it is done. There was some welding done on the front of the frames, a section is boxed with a compression spacer where the stering box mounts. The welding was done with MIG and CO2, but I don't know what wire. 
Parent - - By aevald (*****) Date 02-16-2007 06:21
Hello everyone, I would make one comment on this topic. This is neither in support of welding on frame extensions or not welding them on, but it does have to do with welding hitches onto vehicles as opposed to bolting them on. There is a certain class of hitch that is rated at 10,000 lbs. when it is welded to the frame of the tow vehicle, this IDENTICAL hitch is rated at 6,000 lbs. when it is bolted onto the vehicle. Go figure, it would probably be a good idea to consult with the state highway patrol in your area to see what their views are with regard to your idea for installation of a hitch on this particular vehicle. They would likely be able to provide you with the proper information to make this a LEGAL installation so to speak. Truthfully though, in todays sue happy society you can probably never completely cover yourself. Best of luck and regards, aevald
Parent - - By darren (***) Date 02-16-2007 12:57
no matter how you solve the problem have the vehicle safety certified so as to pass on the liability to the certifying body, whomever that might be in your area. The reason i would go with the bolts is it is very unlikely that you will need any certification to drill holes although you may require a engineers stamp. as usual aeveld is correct ask the highway patrol and get whatever they tell you in writing because judges aren't so interested in what someone 'told you'. if it were me i would take it to a hitch shop and let them take on the liability for the extra cost it would be for them installing instead of you.
Parent - - By jwright650 (*****) Date 02-16-2007 13:06
Don't forget to use the correct grade of bolt...just any ole bolt laying around might not do.
just a thought
Parent - By MDG Custom Weld (***) Date 02-16-2007 15:09
I was waiting to here someone say it, but Jon is right.  The standard TSC, or farm grade 2 or 5 bolt might not be enough.  We always use grade 8 minimum when bolting accessories to frame rails, and in high vibration applications, we use L9 bolts.  I'm not apposed to either option welding, or bolting, but some legal statement in writing from a DOT certified individual should be acquired.
This kind of modification is done every day somewhere, some people do it right, others just do it.  When it comes to safety of me, my family, and others around me, we take no short cuts.  Like someone already mentioned, you can weld a million welds, and everyone only remembers the one that failed.
Proceed with caution, make the right decisions, get the proper inspections, and go on your way with confidence that when you hook up the 12k dozer to the back of your rig, you and everyone that passes you on the road are safe.
Just $.02 for what it's worth.
Parent - By webbcity (***) Date 02-16-2007 15:43 Edited 02-16-2007 15:49
chapman , i'm going to foward you a web site might have some info. you can use . as far as welding it is done every day some where  you need your engineer to design the connection and type of fastners to be used  for welding it should be welds for type of service needed ( some artic conditions the welds and also bolts actualy fall off from the wrong design ) then you need to make shure it will pass dot inspection . the inspection should also be done yearly .  good luck . willie
Parent - - By chapman14219 (*) Date 02-17-2007 17:17
thanks all for the replies

Ill have to ponder my options....the bolting would work i suppose...that way I would want to use a bit heavier stock than the frame for the formed - inside the frame channel pcs....I planned on at least gr8 bolts...just feel welding WOULD be stronger...the frame alloy was a concern though....perhaps  Ill get some formed plates made of a mild alloy instead of mild steel

the reason I asked is my being aware of that legal liability and my basic responsibility to be as safe as possible.

any info from the lab guy at the plant would be welcomed.....Im not overly nervous welding this since Fords here in Buffalo rust out and Ive repaired a few f-250 plow truck frames in front spring area near the rear spring mount with good results...using 7018 stick....always wondered about the frame alloy though....

thanks fellas

Parent - - By DaveBoyer (*****) Date 02-18-2007 06:58
Chapman, I havn't heard from the former lab manager, but I will send an Email to 2 others that worked there as test engineers back then.
Parent - By chapman14219 (*) Date 02-18-2007 19:34
thank you...will ck back.
I wont be doing this for a while anyways...its still in the teens here....

appreciate it

Parent - - By chapman14219 (*) Date 02-22-2007 18:47
wonder if you could check with your contacts and see if they can comment on whether there was a difference in the f-150/250/350 frames (late 80s-up to 1997)....except for differences in front suspension brackets between the f-150 and the F-250/350 ...I believe they are the same....can you confirm this for me?......thanks
Parent - - By DaveBoyer (*****) Date 02-23-2007 06:04
In the mid '80s to '91 while I worked for Dana, the differences were material thickness. The 150 was the thinnest, the 250 was thicker and the 350 was thickest at .240". The front crosmemember was thicker as the GVW of the trucks increased too, and thicker on the diesel. Our plant made the longer frames and the cab/chassis dual wheel frames. this was 3 lengths, 3 material thicknesses, and 2 contours as the pickup and the cab/chassis differ in the width at the rear spring mounting, but are the same width foreward. That is a lot of changeover parts for the tooling. These frames used the "Twin I Beam" front suspension, mountings were the same place and shape on all, probably thicker on the heavier trucks, I don't remember those parts as well, but they involved the front crosmember. The newer 150 frame, code PN38 was under development, but prototypes werent started while I was there, or maybee that was done someplace else.
Parent - - By chapman14219 (*) Date 02-23-2007 18:29
thanks Dave.....I always wondered if the frames were the same or not.....must be SLIGHT matl thickness difference...because by the time they get rusted up a bit from use in the rust belt...they all look the same by eye & the F-150 frames are pretty ez to come by....all holes are there to put larger F-series leaf spring brackets I naturally assumed they were the same......makes me wonder why they punched the holes in the f-150 frames then.....I guess maybe they stamped on the same presses...with the same die setup and only adjusted for matl thickness.....just sounds like a lot of die wear and money ...esp since so many more f-150s are made than anything else....

Very kind of you to ck that out....thanks again
Parent - By DaveBoyer (*****) Date 02-24-2007 08:24
That tooling is a major investment. It is much cheaper to build 1 set of tools and a lot of changeovers than to build seperate tools for each model. The new 150 is a completly different frame I think. I believe the thickness on an old 150 is about .170"-.180" where the 350 is .240". With paint, rust and mud You would have to look close to see the difference. Some of the 150's may have had the heavier spring hangers, they are not all the same GVW. There were a lot of changeovers on the blank and perf tools, there was even a different hole configuration at the front for the ones intended for snow plows.
Parent - - By CWI555 (*****) Date 02-19-2007 00:12
A few key verses from relevant federal laws.


Sec. 30112. Prohibitions on manufacturing, selling, and importing noncomplying motor vehicles and equipment

GENERAL Except as provided in this section, sections 30113 and 30114 of this title, and subchapter III of this chapter, a person may not manufacture for sale, sell, offer for sale, introduce or deliver for introduction in interstate commerce, or import into the United States, any motor vehicle or motor vehicle equipment manufactured on or after the date an applicable motor vehicle safety standard prescribed under this chapter takes effect unless the vehicle or equipment complies with the standard and is covered by a certification issued under section 30115 of this title.

NONAPPLICATION This section does not apply to

the sale, offer for sale, or introduction or delivery for introduction in interstate commerce of a motor vehicle or motor vehicle equipment after the first purchase of the vehicle or equipment in good faith other than for resale;

a person

establishing that the person had no reason to know, despite exercising reasonable care, that a motor vehicle or motor vehicle equipment does not comply with applicable motor vehicle safety standards prescribed under this chapter; or

holding, without knowing about the noncompliance and before the vehicle or equipment is first purchased in good faith other than for resale, a certificate issued by a manufacturer or importer stating the vehicle or equipment complies with applicable standards prescribed under this chapter.

"" In short if you alter, manufacture, or other wise create something that doesn't meet federal standards you could be in trouble. You could not claim ignorance if you welded, bolted or otherwise modified the motor vehicle in question. introduction to interstate commerce is to vague a term for me to be comfortable with. ""

COMMON LAW LIABILITY Compliance with a motor vehicle safety standard prescribed under this chapter does not exempt a person from liability at common law.

"" Even if you complied with the entire section, that one caveat allows you to be sued""

Terms used to describe types of businesses regulated by NHTSA:

Manufacturer means a person or business manufacturing or assembling motor vehicles or motor vehicle equipment or importing motor vehicles or motor vehicle equipment for resale.

Alterer means a person or business making changes to a certified vehicle. These changes do not include the addition, substitution, or removal of readily attachable components, such as mirrors or tire and rim assemblies. Nor do they include minor finishing operations such as painting. "Alterer" also means a person or business who alters a certified vehicle in such a manner that its stated weight ratings are no longer valid. All of these changes are made before the first purchase of the vehicle in good faith for purposes other than resale.

" if you modify it, you are included in this definition. "

"" I've only looked a little bit and find several things disturbing already. I strongly suggest you reconsider your plans"
Parent - - By DaveBoyer (*****) Date 02-19-2007 05:25
Sorry state of affairs in the [SUE HAPPY] USA. From what I have seen on the 2 new F550 dump trucks We have at work, it would not be dificult do design, build and install a more reliably attached hitch than what the dealer who built these trucks from a cab & chassis supplied Us with. The first one was bolted and welded to the back of the frame rails, some of the bolts sheared and the weld failed in a few months of service. The dealer replaced the bolts and re-welded it. We changed the pintle height to remove some of the load on the hitch and used a proper pintle hook instead of the ball/hook combination that came on it, and reasigned this truck to a different crew that doesn't tow anything. The other truck is only slightly better designed, but We had already changed the pintle height and it seems to be holding up. The only good thing about this is that the liability is on somebody else. If You make any modifications, follow any guidelines You can, get the modification approved or whatever, but for damned sure build it strong enough that it isn't the weak link, or a contributing factor in any type of failure.
Parent - - By DaveBoyer (*****) Date 02-21-2007 03:24
Chapman, I got an Email from the plant lab manager. He said the material is weldable by MIG or stick, it is similar to SAE low carbon hot rolled, and is generally aluminum killed for some grain refinement. Use Your best jugment and good luck.
Parent - By chapman14219 (*) Date 02-21-2007 09:22
thanks Dave
I suspected it was mild sparks off a grinder like mild steel and like I said...Ive repaired plow truck frames and it welds nice ...havent had any cracking I guess when the weather warms up a little...Ill have to get going on this....

thanks again..

Parent - - By darren (***) Date 02-21-2007 10:28
Awesome research Dave, its info like that that make this such a valuable forum.
Parent - By DaveBoyer (*****) Date 02-22-2007 04:25
Glad to be able to help. I am learning a lot folowing this site too.
Up Topic Welding Industry / General Welding Discussion / need to extend F-350 frame for hitch - question

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