Welding on truck frames and hitches?

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I read this in another thread:"Welding across the frame flange like you did can get the vehicle red tagged by the D.O.T. Vertical welds are only allowed if the manufacturer allows it and they never do. The D.O.T. is really coming down hard on that stuff now."Where do you find out this kind of information?  What about welding on trailer hitches.  I am sure I will open up a can of worms with this, but I would really like to know the dos and don'ts.
Reply:Manufacturers upfitter manuals are your best resource.Beck's Welding and Fabrication, Inc.-Misc. Metals Fabrication & Installation-
Reply:Originally Posted by CraboWhere do you find out this kind of information?  What about welding on trailer hitches.  I am sure I will open up a can of worms with this, but I would really like to know the dos and don'ts.
Reply:Truck frames have to be welded per manufacturers instructions. To protect themselves they all say, at least to my knowledge, that no welding is allowed. You can contact the manufacturer for their approved welding procedures. Here is a link to the dot reg.http://www.fmcsa.dot.gov/rules-regul...px?reg=393.201A good rule of thumb is never weld across a beam, only lengthwise.Last edited by welderj; 08-10-2013 at 10:41 PM.
Reply:Originally Posted by welderjreg=393.201[/url]A good rule of thumb is never weld across a beam, only lengthwise.
Reply:Originally Posted by CraboWhat is the reasoning here?
Reply:So, if you had a trailer hitch that was welded on, with welds running both across the beam and parallel, the area for potential weakness is at the vertical weld?  Would a gusset either a solid piece, or heavy square tubing be a good way to ensure that stress risers do not occur?I hope the drawing makes sense.  It is welded where it is orange. Attached Images
Reply:The vast majority of hitches are bolted on, even on big trucks. This avoids the welding on frame issue all together. The factory hitch on my F550 looks somewhat similar to your sketch, and is rated at 18K from what I remember. It's held on with bolts, Big bolts. There are 3 3/4" bolts on each side of the 8" channel that connects the cross bar with the receiver assembly to the vehicle frame..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:In this case you are on the end of the frame so the reasons not to weld are not as important. Even on a truck frame it's ok to weld behind the suspension, such as welding on the pivot for the hoist.If you need to weld in the middle of a beam then avoid welding across the flange or vertical.  If you have to, try to put a radius or weld at an angle.
Reply:I used to work for a "body builder" also known as an "upfitter" for 16 years for a large well known company. As mentioned above, follow the chassis mfg guidelines. Larger truck chassis' are heat treated for strength so they can get more capacity out of a lesser amount of iron, so welding counteracts this purpose and can cause serious problems in load bearing areas.What I can tell you we did on a daily basis regardless of the truck chassis maker:1. Weld any where any position as long as it is 2" aft of the rear axle spring hanger. We mostly used .045 flux core with CO2 but the chassis paint is murder and must be ground off or you will pay.2. All trailer pintle hithes were welded on unless the customer requested a bolt on. These mostly consisted of heavy 6" to 8" structural channel with side gussets and strap braces.3. NO welding period anywhere forward form the 2" rearward postion as mentioned above. We may weld a small bracket on a formed cross member for electrical and hydraulic purposes but nothing for structural strength.4. Anything forward of the rear axle spring hanger is bolted on either using u-bolts or shear plate bolt on or huck bolt method.
Reply:Originally Posted by CraboSo, if you had a trailer hitch that was welded on, with welds running both across the beam and parallel, the area for potential weakness is at the vertical weld?  Would a gusset either a solid piece, or heavy square tubing be a good way to ensure that stress risers do not occur?I hope the drawing makes sense.  It is welded where it is orange.
Reply:The manufacturers upfitter guide will tell you all this stuff.  Ford prefers that you weld vertical on the web of their frames and forbids welding on the flanges or radius.  They also go over specifics to lengthening and fish plating the frame.  If you are going to be working on trucks, you really need to have the factory upfitter manual.https://www.fleet.ford.com/truckbbas...esRec_v1-0.pdf  page 10 touches on welding on the frame.  Even tells you what electrode to use.Beck's Welding and Fabrication, Inc.-Misc. Metals Fabrication & Installation-
Reply:I really appreciate this information.  I am still taking classes in Collision Repair, even though I have been doing it for 40 years and teaching the last 20, just to keep up on the changes in technology.  A person cannot know everything.  I have always thought that it was just as important to know who to ask for info as well as knowing it yourself.
Reply:Originally Posted by Stick-manIf you stay here long enough, you'll learn that you're not allowed to weld, PERIOD!!!
Reply:The back of my truck is one BIG trailer hitch and there is not 1 bolt to be found anywhere!100% Welded....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by GravelThat's funny because it is true!
Reply:Well since this was in regards to my thread, I don't think the 8 one inch welds to hold the angle on are going to destroy the frame. DOT is also not an issue for that truck since it will spend it's life hauling silage less than 5 miles on gravel. The angle was used to space the gap for setting the lumber over. Sent from my SCH-I535 using Tapatalk 2
Reply:Antibling, this question was about the trailer hitch on my truck.  I also remember someone talking to me about welding on a truck frame where they put some C Notches in the frame to lower it.  They mentioned only welding horizonally, and not to weld vertically.I did take the quote out from your thread so that it did not hijack it and make it sound like we were discussing your work.
Reply:Does the "no cross welds" also apply to trailers?  My new to me trailer doesn't have enough support going from side to side underneath so I'll be adding more support.
Reply:Can't answer this question with anything but a guess without pics. Yes it's not good to weld across trailer frames but sometimes you have to depending on the design. If the members are welded under the frame like on a car hauler then I would not weld across. If they are above like a flat deck then it's not so bad since the stress is down mostly and the weld is on top, so the stress is mostly compression. Besides most of the main beams on flats are a little over size. Not so for most care haulers.
Reply:Thanks.  It's a 5'x8' trailer.  The original, single cross support, is welded. I'll just bolt the next ones just to be safe.
Reply:Also, there is a HUGE difference in a 'truck' and a 'pick up'. ATruck is a semi, not a Chevy half ton. So welding a trailer hitch on a Chevy, and welding on the frame of a Mack truck, are two totally different animals
Reply:Originally Posted by Stick-manIf you stay here long enough, you'll learn that you're not allowed to weld, PERIOD!!!
Reply:Never ever drill the top or bottom flanges of a frame rail either,Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Originally Posted by walkerAlso, there is a HUGE difference in a 'truck' and a 'pick up'. ATruck is a semi, not a Chevy half ton. So welding a trailer hitch on a Chevy, and welding on the frame of a Mack truck, are two totally different animalsI was always told to never weld on the flanges of a truck chassis, the reason being that it needs to be able to flex up and down, which welding across would prevent, and also add a stress point. Sound accurate to anyone?IW Local 580 NY, NY
Reply:This is how we do it round herehttp://weldingweb.com/vbb/showthread.php...ght=semi+hitchCould have welded it but with a mag base drill and annular cutters its only about 30 seconds per hole.Lincolin Power Wave 450, Lincoln Powermig 255, Lincoln Pro Mig 140, Lincoln Squarewave Tig 275, Miller Big 40 G(with Hobart Hefty suitcase), Thermal Arc 95S and Esab PCM875 in an already full machine shop.
Reply:Originally Posted by AntiblingNot really anymore, newer pickup frames are heat treated the same as semis. Sent from my SCH-I535 using Tapatalk 2
Reply:Originally Posted by CraboSo, if you had a trailer hitch that was welded on, with welds running both across the beam and parallel, the area for potential weakness is at the vertical weld?  Would a gusset either a solid piece, or heavy square tubing be a good way to ensure that stress risers do not occur?I hope the drawing makes sense.  It is welded where it is orange.
Reply:Originally Posted by welderjThe problem with your pic here is not welding or bolting as I see it. It's more that you haven't spread the stress over a large enough section of frame. Commercial hitches have a heavy gusset that goes 18-24" forward from the rear tube. This is to transfer the stress over a large section of frame to help keep the frame from breaking. If your truck is old enough to be off warranty and you can weld a decent bead go ahead and weld it. I would take a piece of 1/4" or even 5/16" plate and make a gusset that goes at least 18" forward and run the tube through it so you get good welds on both sides the plate and weld the plate to the side of the truck frame. You can also bolt it through the frame if you like.
Reply:Nice design, I like it. Since it's a much heavier frame than a standard pickup frame you don't need to get carried away with a gusset either. I would put something about 9-12" forward and down to the bottom.
Reply:Originally Posted by tanglediverNuts.
Reply:Originally Posted by VPTIs that your repair?  That new hitch is
Reply:Originally Posted by tackitIf I worked on trucks this what I would invest in, but you would have to charge more than what it takes to buy a six pack, bag of burgers and fries and box of fishing worms.
Reply:in my long passed youth i worked in a tank shop. we made 6,000 gallon gasoline tankers for local delivery that were mounted on mack chassis which had to be extended by a foot or so. we used brake formed channels and an 8 gauge splice plate. the company engineers wanted us to weld all round except for corners. they were always warning us not to use the torch on the rails which seemed strange. we could weld but not cut? go figure.i.u.o.e. # 15queens, ny and sunny fla
Reply:Originally Posted by farmersammThese are ABSOLUTE BS!!!!!!!!!!!!!  If the idiots working on the trucks would use a torque wrench this wouldn't be happening!!!!!!!  Now you're forced to use this expensive crap to do simple frame repairs  It's merely an idiot proof torque wrench for HOW MANY DOLLARS?????!!!!!!!And yeah, I've seen it first hand!!  Azzholes who did my truck alignment just used a 3/4" drive impact to retighten the u bolts WITHOUT CHECKING WHETHER THE TORQUE WAS CORRECT.  If you don't torque to specs you don't put a stretch on the fastener, and it won't hold like it's supposed to.  On the other side of the coin........over torqueing will result in over stretching, and the fastener will fail.Gotta say it's great marketing though.  Co@@suckers are making it so that every stinking thing requires a special tool
Reply:The biggest advantages to the Huckbolt fasteners are fast consistent assembly and the fact that they are truly vibration resistant. Another alternative is to use tourqe control bolts where the head has a reduced size driving head that is meant to shear off at a given torque . The problem with trying to torque large suspension and frame fasteners is getting acess to torque them, besides having equipment to accuaratelly torque them. I have yet to see anything bigger than a 600 foot pound torque wrench much less a multiplier in a truck shop.Miller xmt304,  Miller S22 p12, Miier Maxstar SD, Miller 252 w 30A, Miller super32p12, Lincoln Ranger 9, Thermal Arc 181I with spoolgun, Hypertherm 10000 ,Smith torches. Esab 161lts miniarc.
Reply:Yes be careful on truck frames, and the posts here are true.  I have seen several frames that have been stretched by various companies, and in fact found a broken stretch frame weld on a new Propane truck, (weld was vertical....shame) inspection last Oct. in Dickinson, ND.  I have repaired many frames on trucks built in the 70's, but tricky....and they have to be railed with additional support material.  We do a fair amount of trailer frames, only certain types, and we have engineered the repair/fix for them to keep our liability at a minimum. Today's truck frames, I will not touch due to liability....let somebody else take the hit when there is an accident.  Trailer hitches???? Even with all our certs, my insurance company forbids it.  Heck my insurance company wont let me weld a pintle eye on a trailer tongue.  I send it out.Good luck!Miller Big Blue Air PakMiller 350P, Python GunHyperthermsSpool gunsMetabo GrindersWe "dooit" as a family...."a family that sleds together stays together"......from sleddin to campin to 4 wheelin to workin.....gotta enjoy life somewhere!