strengthening trailer frame

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hello allfirst time poster, how's everyone doing?i'm reaching out for some help with my trailer project. i picked up a bolt-together trailer from Harbor Freight (i know, i know...) and i'm wanting to strengthen the frame and, while i'm at it, also modifying the design to better suit my needs.this is what the underside of the frame looks like:[/URL]any tips on strengthening the layout? i found this on another forum:i will probably (at least) do that much to mine to give it a little more strength but is there something else i can do to complement?also, like i said above, i'm modifying the trailer in two ways. 1) i'm going to add a central draw tube running all the way down the trailer (which shouldn't be too complicated) and 2) i'm swapping the leaf suspension to a torsion bar (IRS) setup i got from an old subaru to copy: i picked up the same torsion bar set up but haven't started fabbing up mounts for my trailer frame. any ideas as to what the best way to do it would be? unfortunately, my frame is slightly wider than the mounting points for the suspension (by about 6") so i will have to supplement the frame somehow to create a solid mounting point. this is the what the subie suspension looks like:i would appreciate any ideas with this, thanks!
Reply:simplify your life use the leaves and be done with that.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:Ill try and grab a pic tmw of my HF trailer.  I bent the sh1t out of the tongue when I dropped some stuff on it with the skid steer.   Anyway, I basically made an A frame to go under the 4x8 bed.  I extended to A frame out to the edge of the tires too. I think its 4" C channel that I used.   Reused original coupler from the HF trailer.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Sell what you have and buy something that's suitable for what you want to do.There are a couple problems with your ideas. #1 is those trailers have a very limited weight rating and that new axle will eat up a good bit of your payload. Weight rating isn't just about what the axle can hold, it's also about what the frame itself can support among others. Trying to reengineer the whole design idea so you can cantilever the axle supports off the side of the frame is just a bad idea. 2nd the frame material itself is very thin and light weight. This gives you a bunch of other issues. First there really isn't a bunch of built in "extra" strength. You may add a heavier duty axle, but the frame itself wouldn't be able to support the added load. Welding up the connections won't add "strength" to the material. All it will do is prevent the connections from coming apart. Also because the frame material is so thin, you will have to be very careful when you go to weld it. Undercut will significantly weaken the material one something this thin. By the time you are done with the new axle, scrapping out all the original frame material to go with heavier tube/channel to support a heavier load... You aren't going to have much left of the original trailer except maybe the lights and coupler. Sounds pretty pointless to me and not at all cost effective. Just buy a better trailer... Then we get into the whole are you capable of welding a trailer thing. Tacking up the connections is one thing, assuming you leave the bolts in as well. As long as you don't have undercut and weaken the material the original connections will still support the frame. Welding up a frame from scratch is a different story however. Trailers are not "learning" projects. If you don't have a 230v capable machine and the ability to do code quality welds in all positions, every time, you probably shouldn't be building one from scratch.You are trying to turn a sows ear into a silk purse. Not going to happen. By the time you accomplish what you want, you'll either have almost no payload left, or you'll have spent so much money and time on this that you would have been miles ahead simply buying  good used trailer that will do what you want..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:I think you're gilding the lily and will still only have a gilded lily when you're finished.I'd be willing to BET that some bean counter along the way made the HFT design just BARELY strong enough to claim whatever capacity it claims...and not a lick stronger. In other words, they used the lightest possible materials they could, to make the thing as cheaply as they could.If so, what that means is that if you strengthen every "link in the chain" except ONE, the finished product will still only be as strong as the weakest link in the chain ... in other words, no stronger than it was before you started ... except that its usable weight capacity will be REDUCED by the weight of all the crap you welded on.So what you'll have done is invested a lot of time and $ in material into making something WORSE than what it was before you started.In other words, LOSE-LOSE all the way around.If the HFT trailer is not strong enough for you as it sits, I'd get rid of it and get (or make from scratch) something that is.Good luck.
Reply:I am out of popcorn already.Member, AWSLincoln ProMIG 140Lincoln AC TombstoneCraftsman Lathe 12 x 24 c1935Atlas MFC Horizontal MillCraftsman Commercial Lathe 12 x 36 c1970- - - I'll just keep on keepin' on.
Reply:One of the reasons the metal is super thin is how they rate the trailer in the first place.They are rated with even load distribution.  Think boxes covering the entire floor.If a point load rating was used, it would take much less weight to fold it up.About the only true ratings on those trailers are the hitch, axle, tires and springs.But I tend to be biased against that bolt together crap - lol Dave J.Last edited by MinnesotaDave; 04-28-2013 at 01:42 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:I have the same trailer, welded every joint and welded the tilt joint too. Its not a bad trailer, but it isn't a great trailer either. I've loaded the crap out of it with at least 2000lbs of wood from the forest, it handled it without issue. I'm going to modify it a little, like boxing the hitch arms and going to larger tires, and put a new deck on it cause the one that's on it is rotting, but for the $129.00 I paid for it, its been priceless.HF 180 amp/240 volt Mig (cap mod)1987 Harley FLHTP (project)1990 F350 XLT Lariat S/C dually1990 S&S 11SC Cabover Camper2011 Ford Ranger S/C XLT
Reply:Sell it!Save your money that you were going to throw away on it and buy a real trailer!
Reply:Use it the way it is , you cannot build a trailer for what tractor supply and big tex can sell them for.
Reply:wow, i'm very surprised by the comments thus far.i understand this is a crappy trailer (i'm not an idiot, i bought it knowing that) but this is the *welding* forum, right? what i mean is, i thought i would post and get some constructive ideas on how to pursue my project. [disclaimer: i understand some of the 'sell it' comments are coming from people with good intentions but i really don't want to sell]ok, let me explain why i'm doing what i'm doing (maybe it will make more sense): i'm replacing the leafs with the subie setup because:a) it will allow me to have IRS (important for the uses i intend) b) it actually weighs about the same as the existing axle/spring combo and should be comparable in terms of load capacityc) it will allow me to run matching wheels and height with my 4x4 truck. d) i will be able to run a parking brake on it. this trailer is rated at 1800lbs and trust me when i tell you it has no problem hauling at least 25% more than that without a problem because i've done it. in short, load capacity is not a top priority to me but versatility is and this little trailer offers all the options i need. it's a good platform for me and if i needed a heavier duty trailer i would not be messing with this one. i simply want to make *this* platform as strong as possible and have it work with the IRS suspension. i understand people aren't fans of HF (neither am I) but sometimes good deals just fall into your lap. so... if folks could please help me with welding ideas, i would greatly appreciate it. to those of you who already have, i will address people's posts/comments below. thanks!
Reply:Originally Posted by dumb as a stumpsimplify your life use the leaves and be done with that.
Reply:Originally Posted by soutthpawIll try and grab a pic tmw of my HF trailer.  I bent the sh1t out of the tongue when I dropped some stuff on it with the skid steer.   Anyway, I basically made an A frame to go under the 4x8 bed.  I extended to A frame out to the edge of the tires too. I think its 4" C channel that I used.   Reused original coupler from the HF trailer.
Reply:Originally Posted by DSWThere are a couple problems with your ideas. #1 is those trailers have a very limited weight rating and that new axle will eat up a good bit of your payload. Weight rating isn't just about what the axle can hold, it's also about what the frame itself can support among others. Trying to reengineer the whole design idea so you can cantilever the axle supports off the side of the frame is just a bad idea.
Reply:Originally Posted by KelvinIf the HFT trailer is not strong enough for you as it sits, I'd get rid of it and get (or make from scratch) something that is.
Reply:Originally Posted by desertscoutI have the same trailer, welded every joint and welded the tilt joint too. Its not a bad trailer, but it isn't a great trailer either. I've loaded the crap out of it with at least 2000lbs of wood from the forest, it handled it without issue. I'm going to modify it a little, like boxing the hitch arms and going to larger tires, and put a new deck on it cause the one that's on it is rotting, but for the $129.00 I paid for it, its been priceless.
Reply:Originally Posted by oiflait's a good platform for me and if i needed a heavier duty trailer i would not be messing with this one. i simply want to make *this* platform as strong as possible and have it work with the IRS suspension. i understand people aren't fans of HF (neither am I) but sometimes good deals just fall into your lap. so... if folks could please help me with welding ideas, i would greatly appreciate it. to those of you who already have, i will address people's posts/comments below. thanks!
Reply:Originally Posted by oiflaok, i understand your point about the 'available' strength, that makes sense. but welding the connecting points is better than not. my intent with the 'strength' issue is to reduce frame flex and to find a good way to mount the subie suspension. the lightness of the trailer is another part of why i am interested in it. a heavier trailer would not work as well for me because i'm intentionally building something light.
Reply:I spent $300.oo on my first trailer that was built from a very old Ford truck frame, said to have been a Model 'A'. I could neither prove nor disprove that, and the deed was already done. In any case, I started adding stuff on the frame to make it stronger, I succeeded in making it 'heavier' for sure!  In the end, I gave it away. But I had a lot of fun learning to weld (beginning to learn that is, I'm not done yet). Go ahead and weld it, it'll be awesome! You'll learn something and prove or disprove your engineering ideas. The guys here are just trying to cut you ahead of the learning curve. It is a nice gesture, but you have to learn for yourself, I find... Attached ImagesCity of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Hi OFLIA I have done trailers before and youd be far better off to sell this trailer and start from scratch with the proceeds...get your weld skills up to snuff (if they arent already) and go from there...that way its built for the suspension you want instead of adapting it plus you will be able togive it good balance/weight distribution from the get-go.Its not rocket science to build a good trailer but you do need to be able to make good welds (not "good enough" and not "good looking" ones that didnt fuse properly) plus use some common sense in the design.Im afraid that by trying to adapt the HF trailer to what you want you are going to use up more time and expend more money and energy than going from scratch...Hobart Stickmate LX235AC/160DCRanger 305GVictor 315 O/A rigHope to acquire in the next couple of years: Hypertherm PM45 and Dynasty 200DX
Reply:Here is pics of mine and the channel in front of axle goes across whole width of trailer. Attached ImagesTiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:I have seen some of the HF trailers, my first impression , as I have built many trailers, is they are not anything I would use, I say this because I haven't really looked close at them, what guage is the metal and what are the dimensions, I do think I remember them being formed 3 sided channel. Also they do have a few different ones including some folding unit.  Now the point I'm making is like the others, after you discard the axle and wheels, what is left, a tin frame and probably the cheapes lights that can be had. Why not build something nicer , stronger. between your financial investment and your labor/ time investment , I cannot speak for others but I don't understand your special need for this simple light duty frame.  I wouldn't buy a house and throw away the foundation to get my own , Even from memory, I would not attempt 1800 on anything HF. Don't forget about the dynamics of bouncing down the road.   You have decided to weld up the corners and thats good, what else do you want to know, I say if you have to use this trailer and want to make it stronger , build a 4'X8' 3" channel subframe and put your trailer on it. Will that help?"Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Screw the popcorn......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 kolotI have seen some of the HF trailers, my first impression , as I have built many trailers, is they are not anything I would use, I say this because I haven't really looked close at them, what guage is the metal and what are the dimensions, I do think I remember them being formed 3 sided channel. Also they do have a few different ones including some folding unit.  Now the point I'm making is like the others, after you discard the axle and wheels, what is left, a tin frame and probably the cheapes lights that can be had. Why not build something nicer , stronger. between your financial investment and your labor/ time investment , I cannot speak for others but I don't understand your special need for this simple light duty frame.  I wouldn't buy a house and throw away the foundation to get my own , Even from memory, I would not attempt 1800 on anything HF. Don't forget about the dynamics of bouncing down the road.   You have decided to weld up the corners and thats good, what else do you want to know, I say if you have to use this trailer and want to make it stronger , build a 4'X8' 3" channel subframe and put your trailer on it. Will that help?
Reply:I have to add.  Maryland has similar rules.You build trailer, get temporary tags (i.e. wait in line at MVA).Next you bring trailer to MVA with police inspectors.  They look it over and if they are OK with it (whatever that means) they will issue you a VIN.Next you take it to an inspections station.Then when you are all done, you go back to the MVA.  Theoretically a shorter line this time.... (HAH!)VIN number is a sticker - easily falls off after a few years.  Only description on the trailer is brand name (abbreviated), number of axles and of course the load range.According to the brainiacs at the MVA, if I buy the trailer assembled, I don't need to go through inspection...   In my case, I bought a Home Depot trailer, assembled it myself, and the MVA 'accidentally' issued me tags (no inspections etc.)  Somehow, they assumed that if Home Depot assembles the trailer it doesn't need any further checking.  I personally suspect that if the person at Home Depot knows how to set the pre-load on a tapered bearing, they wouldn't be working at Home Depot...As for the strength of the trailer.  They have to be built stronger than they are rated.  Margin of safety for when that trailer is at max weight, max speed and hits that over-sized pot hole.To increase the strength, gusseting the corners isn't going to do much.   While I've seen trailers 'racked', I've never seen one fail that way.   That being said, the idea of changing suspension types is a bit more worrying.  Leaf springs effectively put force on the trailer in two spots.  Torsion tubes tend to concentrate the loads.  By spreading a load on two points vs. sheer, you make the assembly 4x stronger.  I'm not sure about that IRS setup, but you might want to consider an extra twisting force as well when one wheel is loaded and the other is not.Nothing insurmountable.The only drawback on cheap trailers that I see is tires and paint finish.  That being said, my HomeDepot trailer has lasted about 15-18 years (I think I got it around 1995).  I've replaced an entire frame rail (one side was 'stuck in the mud' and rusted from the inside).  They seem to powder coat over anything that doesn't move out of the way and the steel they use is prone to rusting (more than 'good stuff').   The bearings they use are crap.  The rubber dry rots rather quickly (put some green goo in it).I have spent way too much time on this trailer.  Everything from fixing the wiring (wiring rotted out) to putting on rails, to putting on LED lights (and of course fixing rot).I'm a better weldor/fabricator now.  If I could get the steel cheap enough I would build my own.  I've seen trailers with the C channel facing out.  I believe that would give you less places for the rust to hide.  I'd also run the wiring in accessible conduit (vs. through the frame).  LED lights are the only way to go (I was pulling bulbs and cleaning corrosion off them with the cheap lights).$50 dollars here, $100 there, hours of sanding, welding, painting etc.  It adds up quickly.Oh and I believe someone suggested the bigger tires.... Well, for short distances and light loads you can exceed the 45mph speed limit on those golf cart tires they put on there, but you really want larger tires and associated wheels and hubs.  A trailer that isn't rated for highway speed is useless.So at the end of the day, the only thing you are keeping is a square box made out of sub standard tubing, with crappy paint and a propensity to rust...   Build your own box.http://www.trailerplans.comCon Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DXOriginally Posted by con_fuse9So at the end of the day, the only thing you are keeping is a square box made out of sub standard tubing, with crappy paint and a propensity to rust...
Reply:Originally Posted by KelvinKinda like the gold leaf on the lily after the lily wilts!
Reply:Use the force............... Do you think Darth Vader really new his stuff when constructing his death star!!You have had some useful info here that is good but the bottom line for me is you know your loading max and essentially welded flat triangle's should take up the 6" slack on the rolling gear ( with gussets).Other than that overload on those bumpy roads n you'll moan when the stress fracture's appear.
Reply:Originally Posted by MaccanoUse the force............... Do you think Darth Vader really new his stuff when constructing his death star!!
Reply:Originally Posted by DSWHey, he at least had plans to work from....
Reply:Originally Posted by tanglediverCaptured the plans, did we. Yet many operatives met their fate to overcome Vader.