Flatbed Trailer

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Time to get started I guess.Got some working drawings together.I've removed all dimensions, and a good deal of important specs, because I'm not in the business of providing plans.  I figure everyone ought to be able to provide their own.I'm using the chop saw for all cuts.  It's more accurate than flame cutting, and the cleanup is non existent (a real time saver)The rear crossmember is roughed in with plasma, then fine tuned with a cone stone on an angle grinder.All so's I can get fancy with these flush mounted DOT lights  And NO, those aren't my Vodka boxes  Got some glassware stored in them  Beer only at this place"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Looks like a good start Samm. What size/capacity is the trailer going to be? the pictures get cut off on my phone so if it says somewhere i can't see it.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Sambo, LED or light bulbs in the lights?Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools.
Reply:The picture is sad. NO SNOW !!!!!   You want me to send some, will add COLD for free !  looks like about 16'. What do you have for axles, springs, and tires ? I no, those mobile home ones right ? I do not like those open rim wheels and the rim locks. Just a personal thing.
Reply:Originally Posted by BD1The picture is sad. NO SNOW !!!!!   You want me to send some, will add COLD for free !  looks like about 16'. What do you have for axles, springs, and tires ? I no, those mobile home ones right ? I do not like those open rim wheels and the rim locks. Just a personal thing.
Reply:I forgot about his earlier posting.  NOW, I see he is buying the real stuff.
Reply:After cutting the crossmembers it's time to set up the frame for tacking.Lacking a concrete, level area to work..........the channel is placed on horses, then eye sighted from the front, and side.  This makes the whole structure planar (flat like a table).  Shims will be added under the 3" tubing supporting the channel to bring it to alignment.  I find that sighting "air gaps" from the furthest distance you can see both ends, on a horizontal plane, is the best way to do this.  Remember that it doesn't have to be level, it just has to be flat.  You could build this thing hanging from a wall, upside down, or or or or............................ AS LONG AS IT'S FLAT AND PLANAR.It was sort of a big decision as to where to place this thing for the build.  I need to be able to access it from the side in order to pick it up with the loader, or crane.  At some point close to the finish, the axle assembly will have to be placed under the frame in the proper position for correct balance.  I'm aiming for a tongue weight of around 250lbs to 300lbs since the tare weight should be around 2500lbs +-.  None of this can take place until the final axle weight is determined (ie. the trailer almost finished with the exception of placing the axles).  Once it's virtually built, I'll use a trailer tongue weight scale to fine tune the hitch weight.  I prefer not to use the "2/3, or 60-40 formula" for axle placement, it's too variable.  I want the tongue weight spot on.Final shimming, squaring, and tacking, will have to wait till tomorrow.  I spent a good part of the day fixing a stinkin' burst pipe"Any day above ground is a good day"http://www.farmersamm.com/
Reply:'Member what I told ya' about hoses Sambo...Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools.
Reply:When I build things like this, or bigger, and I want them flat I use one or the other of these.  Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:Good design. Plate the front with 3/32 Diamond plate.Bubble gumTooth pixDuct tapeBlack glueGBMF hammerScrew gun --bad battery (see above)
Reply:Looks like the wife has a water bowl and rope out there for you. I guess she doesn't want you wandering off instead of working.
Reply:Looks good . On those cutouts for the 40 series lights I would put a piece of sheetmetal on the thin part of the flange to keep stones and whatnot from damaging the lights and connectors.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:Sam it looking good so for please keep us up dated thanks.
Reply:Been shut down because of the wildfire danger.  We've had some bad fires here, not about to weld/cut/grind with this crap going on.Finally got back to it today, had to build another pair of sawhorses for the tongue bending operation  Soaked up the better part of the dayDon't really need the things for the weight involved, but I need to have a flat surface to bend the frame on, so I need something under the tongue part of the channel.5 hours to make some sawhorses  Getting old, and slow."Any day above ground is a good day"http://www.farmersamm.com/
Reply:U shur got a purty metal pile.Arcon Workhorse 300MSPowcon 400SMTPowcon SM400 x 2Powcon SM3001968 SA200 Redface1978 SA250 DieselMiller Super 32P FeederPre 1927 American 14" High Duty LatheK&T Milwaukee 2H Horizontal MillBryan
Reply:Originally Posted by blawlessU shur got a purty metal pile.
Reply:I figured you would have just disked a fire brake around yer welding area.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 CEPWhen I build things like this, or bigger, and I want them flat I use one or the other of these.
Reply:A gotta better idea...Sand Volleyball court.  Take the net down and you have a nice place to work.  Use a magnet to sweep up all the wire stubs, rod stubs, and slag.  That way you can go barefoot.Put the net back up when the weather improves and invite some co-eds over to play...Just a post to subscribe to the thread.  I'm looking forward to seeing this project to completion. Originally Posted by DualieI figured you would have just disked a fire brake around yer welding area.
Reply:Not too much progress due to the bad weather.  The wind has been gusting to 40ish just about every day.  It means no workThe frame is almost completely tacked though.The first problem was dealing with some not-too-straight channel.  It made it impossible to square the structure.  SURE I could have clamped a strongback to the bad piece of channel, but the bend would re-surface later on I feared.Bowed like a banana  Actually maybe 1/2" out of true, but enough to mess things up.Clamped a strongback to it.Then heated the opposite side of the flange to pull it back to true.  IT'S IMPORTANT THAT YOU DON'T GO ABOVE 1200 DEGREES F, OR YOU'LL RUIN THE STEEL.  The steel was heated to below "red", with no visible color.  This was well in the safe zone.  I'll probably get around to investing in a good IR Laser Thermometer after this though.An interesting read for those curious about the technique I've used for many years.  http://www.fhwa.dot.gov/bridge/steel/02.cfmThe flange is heated in a V shape to shrink it.Now it's ready for the final tackup"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I'm exactly square at this point.Squaring is done on the diagonals with the crossmembers in place.  The tolerances on the crossmembers are exact.  This means that all work measuring/tacking has to be done with the crossmembers in place.  It's so tight a fit that you couldn't add the middle crossmember after the end crossmembers are tacked.  Accurate cutting is a good thing for this particular job.When using clamps it's a good idea to center the clamping force on the crossmember web, not the flange.  The web will take straigtline force without the structure being forced out of square.Tacks are done on the diagonals, and time allowed for them to cool before proceeding to the next one.  They're hot, but small as possible too help control distortion.The frame is tacked, and the next step is to bend the channel to make the tongue.  The bend point is where the yellow hammer is sitting.Mornings have been good for a few days, the wind is down.  But it's limited time till the wind cranks up again, so maybe tomorrow I can do my bending"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Looking good Sam. Going to be a very useful trailer
Reply:Looks good . Doesn't the smaller channel fit nicer than the same size with less cutting oft proper fit.
Reply:Interesting choice for cross member material Samm. I was expecting you to have used matching channel and have coped it to match, or gone down to a size so 2x lumber would sit flush with the outer frame. What are you planning to deck it with, steel?.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 would have coped them so they're flush to the top.  Doesn't need to be the same size to do that.  Cope one side.Originally Posted by DSWInteresting choice for cross member material Samm. I was expecting you to have used matching channel and have coped it to match, or gone down to a size so 2x lumber would sit flush with the outer frame. What are you planning to deck it with, steel?
Reply:So you're saying, Sam, that you will only wind up welding the vertical up portions of the cross members to the outside frame rails?
Reply:Have you considered running a torque tube up the middle of it Samm?-------------------------Chemetron AC/DC 300 HFSnap-On MM300L Lincoln SP140 Lincoln AC/DC 225g Lincoln SA200 Lincoln SA200 Miller Bobcat 225GVictor torchesH&M and Mathey beveling machinesMcElroy Plastic pipe fusion
Reply:Originally Posted by handtpipelineHave you considered running a torque tube up the middle of it Samm?
Reply:[QUOTE=farmersamm;3549831]It was sort of a big decision as to where to place this thing for the build.  I need to be able to access it from the side in order to pick it up with the loader, or crane.  At some point close to the finish, the axle assembly will have to be placed under the frame in the proper position for correct balance.  I'm aiming for a tongue weight of around 250lbs to 300lbs since the tare weight should be around 2500lbs +-.  None of this can take place until the final axle weight is determined (ie. the trailer almost finished with the exception of placing the axles).  Once it's virtually built, I'll use a trailer tongue weight scale to fine tune the hitch weight.  I prefer not to use the "2/3, or 60-40 formula" for axle placement, it's too variable.  I want the tongue weight spot on.I would be interested to know how you came up with this precise figure for tongue weight, seeing as how the loaded trailer tongue weight is so variable. With all the trailers that I've built this is one of the hardest things to get right since so many things come into play to get it right, so I'm always interested in how others decide what will work for them.
Reply:[QUOTE=welderj;3599751] Originally Posted by farmersammIt was sort of a big decision as to where to place this thing for the build.  I need to be able to access it from the side in order to pick it up with the loader, or crane.  At some point close to the finish, the axle assembly will have to be placed under the frame in the proper position for correct balance.  I'm aiming for a tongue weight of around 250lbs to 300lbs since the tare weight should be around 2500lbs +-.  None of this can take place until the final axle weight is determined (ie. the trailer almost finished with the exception of placing the axles).  Once it's virtually built, I'll use a trailer tongue weight scale to fine tune the hitch weight.  I prefer not to use the "2/3, or 60-40 formula" for axle placement, it's too variable.  I want the tongue weight spot on.I would be interested to know how you came up with this precise figure for tongue weight, seeing as how the loaded trailer tongue weight is so variable. With all the trailers that I've built this is one of the hardest things to get right since so many things come into play to get it right, so I'm always interested in how others decide what will work for them.
Reply:With, let's say a 250lb empty tongue weight, you can transfer off about 500lbs to the hitch(with a hitch rated at 750lb carrying capacity).  This means the front of the trailer, between the axles and the coupler, can carry about 1000lbs in the center of the span.  This is simplified of course, but it's the general idea behind trailer loading."Any day above ground is a good day"http://www.farmersamm.com/
Reply:[QUOTE=farmersamm;3549831]It was sort of a big decision as to where to place this thing for the build.  I need to be able to access it from the side in order to pick it up with the loader, or crane.  At some point close to the finish, the axle assembly will have to be placed under the frame in the proper position for correct balance.  I'm aiming for a tongue weight of around 250lbs to 300lbs since the tare weight should be around 2500lbs +-.  None of this can take place until the final axle weight is determined (ie. the trailer almost finished with the exception of placing the axles).  Once it's virtually built, I'll use a trailer tongue weight scale to fine tune the hitch weight.  I prefer not to use the "2/3, or 60-40 formula" for axle placement, it's too variable.  I want the tongue weight spot on.I would be interested in how you came up with this figure. With loads being so variable and all the other considerations to take into account, deciding on the best axle placement can be one of the most difficult problems when building a trailer. I would be interested to hear how you came up with this formula.
Reply:OOPS, sorry for the double post.
Reply:I understand HOW your doing it, what my question was is how did you determine that 2-300 pounds of tongue weight on an empty trailer will give you the proper tongue weight when it's loaded? How did you decide, based on your towing vehicle, what was the best tongue weight when loaded and how will the planned load you will haul affect that? I'm just curious how you came to that number on the empty weight when most people position the axles based on the loaded weight.
Reply:I remember seeing this on one of the trailer build sites although I do not endorse nor suggest the accuracy of the information. ;-) The general rule when building a trailer is that there should be a 60/40 percent split in weight when centering the axle. 60 percent of the trailer weight should be placed forward of the axle for proper tongue weight. There is a more detailed method of determining the proper tongue weight for the trailer so that the axles are in the correct location for safest towing and stability. I will outline this process for you.To determine the correct position for the axle determine the trailer weight under the wheels and the tongue weight. This will require a mock up (pre-build) of the trailer. Once these weights are determined you will need to add the two numbers together to get the total weight. Once the total weight is determined you need to measure the distance to the center point of the axle to the center of the trailer coupler.Now figure the percentage of tongue weight, total weight divided by tongue weight, if it is greater than 10 percent you will need to subtract 10 percent of the total weight from the tongue weight and divide by the total weight. Next multiply the answer by the distance between axle center and center of the coupler. The result will give you the distance that the center line of the axles should be moved forward.If you have less than 10 percent tongue weight you will need to move the axles rearward using the following equation. Distance to move rearward will be 10 percent of total weight minus tongue weight divided by total weight then multiplied by the distance between axle center and center of the coupler.Miller MM 211Miller 375 XtremeO/A
Reply:I guess that will give you a good way to build an average trailer. I just thought that with his exact numbers that he had taken more into account, like what he was hauling and where that load would need to be to get the proper loaded tongue weight for his tow vehicle. For instance, if he is using a 1/2 ton pickup to pull this trailer and he's going to haul square hay bales that will be an even load. Then he will need very close to the 40/60 split. If he's using a 1 ton dually with flatbed and the hitch as close as possible to the truck differential he can carry a lot more tongue weight and increase his trailer capacity by moving the wheels back. If he is going to haul cars behind his 1/2 ton then the 60/40 split might be too far back since the weight of cars is concentrated in the front and will mostly be in front of the axles. Also if he is going to haul tractors which have the weight concentrated on the rear axle he may need to move the axles back further than the 60/40 to make sure he can get far enough forward without running the tractor front wheels off the front of the trailer. That's why I was questioning how he got that specific number for the empty tongue weight. It just seemed so specific that I thought he had a specific load in mind is all, otherwise why bother since moving the load 6" fore or aft will change the tongue weight by several hundred pounds on a fully loaded trailer.
Reply:Originally Posted by farmersammI can determine exact EMPTY tongue weight for the build.  Tongue weight should be between 10%-15% of the gross trailer weight (empty).
Reply:Very little actual work time today, but some got done.  The wind is still dangerously high.Was able to put together the adjustable height coupler.After machining the holes, the plate was positioned in a jig.The design leaves me precious little area to build up a weld, so additional weld was deposited under the plate.  To do this it was beveled.And how it turned out........................There was one pass in the bevel, then two built up passes in additionYou can buy premade tracks, but I've played around to tweak the tongue angle on this design.  I'm going to have a 44 degree tongue angle at the coupler.  This will give me a tighter turning radius.  Part of the tweak required that the tongue configuration wouldn't accept a commercial made track, so the custom one.This will give me height options from 29" to 19" at the ball."Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by MinnesotaDaveNot trying to nit-pick, I have a question.In all of the material I have referenced while building, the critical tongue weight measurement is with the trailer loaded.Are you concluding that by setting your tongue weight empty, this will predict your tongue weight percentage while loaded?
Reply:Tongue weight is critical loaded or empty BTW"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I use my pickup overloads as a measuring tool as well - works pretty good I used to haul scrap so at the scale helped my guesses out quite a bit - not as good as your hitch scale, but pretty close.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 suppose you could look at it another way.If you start out with 250 on the hitch, trailer empty..............................Load the trailer evenly EVENLY with the load spread out over the entire bed.  4500lbs on a 7000lb GVW trailer that weighs 2500lbs.You'll wind up with 10% of the weight on the tongue......................  Around 700lbs.......the carrying capacity of the hitch."Any day above ground is a good day"http://www.farmersamm.com/
Reply:what do think about making the sliding sub-frame with some u-shaped long members that would slide around the bottom flanges of the main frame. bolt some uhmw plastic for sliders in the bottom of the slide frame and then no lifting equipment would be needed to alter tandem spacing. pull pins, lock brakes, slide to required location and repin.
Reply:Originally Posted by farmersammI suppose you could look at it another way.If you start out with 250 on the hitch, trailer empty..............................Load the trailer evenly EVENLY with the load spread out over the entire bed.  4500lbs on a 7000lb GVW trailer that weighs 2500lbs.You'll wind up with 10% of the weight on the tongue......................  Around 700lbs.......the carrying capacity of the hitch.
Reply:Originally Posted by farmersammVery little actual work time today, but some got done.  The wind is still dangerously high.Was able to put together the adjustable height coupler.After machining the holes, the plate was positioned in a jig.The design leaves me precious little area to build up a weld, so additional weld was deposited under the plate.  To do this it was beveled.And how it turned out........................There was one pass in the bevel, then two built up passes in additionYou can buy premade tracks, but I've played around to tweak the tongue angle on this design.  I'm going to have a 44 degree tongue angle at the coupler.  This will give me a tighter turning radius.  Part of the tweak required that the tongue configuration wouldn't accept a commercial made track, so the custom one.This will give me height options from 29" to 19" at the ball.
Reply:Originally Posted by GravelSam, if you start with 250 pounds of tongue weight and add an evenly spread load wouldn't you still have 250 pounds of tongue weight?
Reply:(I wouldn't want that trailer behind my truck!)So true...tongue weight is a necessity. A light or negative tongue weight will result in your flipping the vehicle and trailer after it begins to swerve widely from side to side. I know this by experience. Helped move the son n law and did not watch how the trailer was loaded. It was hooked to the truck while he was loading. Anyway at about 70mph I started watching the trailer bouncing from one set of wheels to the other in the rear view. The logo was actually going 45 degrees one way then lurching to 45 degrees the other way. Finally wrestled it back and had to change clothes. Found the tongue weight was neutral. Bought six 50LB bags of rock salt at Walmart and duct taped it to the tongue. With 300 lbs of ballast on the tongue we made the trip uneventful after that.Miller MM 211Miller 375 XtremeO/A
Reply:Now that we're done (I think) discussing tongue weight, it's time to focus on the bend.  THE BENDBecause this is a one-off kinda thing, it sucks sorta.  You are trying to determine measurements as you go along.I figured that the tongue bend had to be at a certain distance along the frame.  I make scale drawings, and figure out stuff from there  This crap is all theoretical at this pointTo find out whether the drawings are correct, and to also find out whether I ought to cut the steel where I think it ought to be cut..........I have to do a mock up.The setup is to determine the angle that the tongue has to be bent.  There was a guy in the Pit that used to do this extensively, he called it building in "the air".  This guy could modify heavy equipment just by extending measuring lines and numbere.............KEWL.Anyhow, I determined that the cut had to be 22 degrees.  Split the 22 degrees, and you have 11 degrees on either side of the 90 degree angle.  Set your carpenters bevel at 11 degrees using a machinists protractor, and have at it.The cuts were made with a Razor Blade (Flexovit)The cuts on the top flange were easy because I could actually see what I was doing, and I'm comfortable working on my feet.The cuts on the bottom flange suffered a bit because I'm not comfortable working on my back in mud.  We're in a high fire danger mode here, and before I do anything that involves sparks, I wet the entire area down with water.  Sucks when you have to lay in it.Anyhow.......the cuts allow the channel to collapse in on itself...a common thing in fabricating.  I'll be making the bends using heat and leverage.  This ought to cause another big controversyBefore the actual bending is done, I have to nibble out a bit more at the root of the bend.  You have to have room for the web to collapse inward on itself.  Room for the radius."Any day above ground is a good day"http://www.farmersamm.com/
Reply:http://www.sherline.com/lm.htm  for Stick ManLast edited by farmersamm; 01-21-2014 at 12:05 AM."Any day above ground is a good day"http://www.farmersamm.com/