Building the frame with 4" X 3" I beam

[davefullmer]

Hello,

I need to ask some advice from some of you experienced builders.

I am settling into a design using Mike's Generic Benroy plans. I want a little larger so I am thinking stretching the plan to 10' long and 5'high.

I would be interested in any comments on that change but the important question tonight is about frame material.

I'm a pack rat and I have lots of room on my 45 acres and back at the edge of my 33 acres of woods I have a pile of steel that I have accumulated over the years from salvage, shop surplus, etc.

This afternoon, I went back to look for what I might could use on the frame and what I have is some fairly hefty 15' pieces of 4" high by 3" wide I beams.

I also have some ligher 4" X 2" I beams I could use for cross members.

My question is about weight and the added height. I am not much concerned about the added weight because my tow vehicle will be a 96 Chev Tahoe. The real question is is the added 2" a concern? I can't personally see any reason why it would matter, other than having the floor a little higher off the ground.

The price is right although there will be some labor getting rid of the surface rust and prepping it for paint.

What do you all think?

Dave

[Leon]

I built a car hauler with a capacity of 10,000 pounds with material as heavy as that. My opinion it is a bit of overkill, and you might be able to take that stuff and work a deal to get some 2x2 instead.

[madjack]

Dave, there are no structuraly problems but that is MASSIVE overkill...I know the price is right and you have plenty of tow vehicle but the weight of the frame alone would be more than most TD's and would cost ya extra everytime you passed a gas station...I would sure try and find something lighter in the scrap pile or sell some of it and getcha some 1x2x3/16th chanell of some 2x2x1/8th tube....
madjack

[Podunkfla]

Dave... I hafta agree with Madjack about the overkill thing. I have a 20 ft. car hauler trailer rated at 10,000 lbs and it is only framed with 2 x 3" 1/4" thick channel iron. Considering you can buy an already built trailer that will work fine for a 5 x 10 Benroy from Tractor Supply, Red Trailers and others for 3 or 4 hundred bucks, It just doesn't seem practical to use such heavy stuff... even if it is free? Maybe you could swap some of it to a local welding shop for a trailer frame built from 2 x 2" square tubing? That steel is worth some bucks to a guy that needs it... Heck, I would have loved to get a hold of something like that when I was building my shop, for headers over 4 garage doors.

[davefullmer]

Thanks fellows,

I had checked with the local steel supplier and 2x2 x 1/8 th wall is "only" $2.08 per foot. 1 stick of 24 feet is more than enough for side rails. I would want 1/4" for the tongue. I think I have enough 2 inch angle for cross members so I guess I will rethink my ideas and buy some 2 x 2.

I work in maintenance at a local stamping/heat treating plant and right now we are building a new continous furnace and are using lots of steel. I can get the supplier to drop off that 24' stick on one of their runs and then on a Saturday, use the Mig welder to weld up my frame.

I am the electrical guy in the plant and I keep telling the rest that I don't weld, so if I do weld up the frame, I will have let the secret out of the bag that I can weld. Truthfully, I don't have the skills the rest of the crew does, but I do want to weld this frame up myself. If I get in problems, I can always ask for some teaching.

Thanks again for your advice. I'll find a use for the steel. Maybe like Madjack says, use some for header across the door of a new garage for the tear.

Dave

[Gerdo]

I think you are wise going with the 2x2. Even though you have a big strong TV (tow vehicle) now you may downsize in the future and may want a lighter TD besides lighter is better on gas milage. I would, and did, use something heaver for the tongue like 2x3x3/16". I figured out after I finished my body that the frame doesn't need to be too strong because the TD body is a "Torsion Box" and is very stiff. My TD is 5'Wx4'9"Hx11'L. The main square of my frame is 2x2x3/16 and my wings and cross peices are 1.75x1.75x1/8. In my opinion, this is also overkill. The tongue is 2x3x3/16 in an "A Frame". I like a frame tongues over a single tube tongue, I have had both, because the single tube can flex side to side and cause a bad sway and the a frame takes care of that problem. I know alot of people have single tube tongues and have no problems, just a personal experience.

[GregB]

Gerdo and Dave,

Forgive me for jumping in to make sure I have this right. I may very well be wrong here, and if so, I will expect an engineer to swoop down and correct me, but I think you mean that the TD body is a monocoque design rather than a "Torsion Box". Monocoque construction means that the structural load is supported by the skin of the trailer, rather than an internal truss system. That is, that since the sides and top and bottom are all firmly fastened together, the box doesn't need an internal frame. We also usually have an internal bulkhead with adds to torsional and lateral rigidity.

Each individual piece (the walls, the floor and the ceiling, the bulkhead) can be made with torsion box construction which is two skins that glue to a core grid (in our case, usually framing and insulation). A torsion box has the advantages of being flat, stiff and light while using a minimum of material.

This is a gross oversimplification, but for our applications, the combination of torsion box pieces, an interior bulkhead, coupled with monocoque construction produces a structure that does not need to use the frame for stiffness, but simply to keep it off the ground and attached to the wheels. Or, as they might say in Boston, it's wicked strong!



Greg

[Gerdo]

Torsion Box, Monocoque? Can't we just be friends. Actualy you are probably right. Either way, the built TD is wicked strong and stiff.

[davefullmer]

Yeah,

Either way, once I saw the way the sides should be fastened to the side rails I saw that the frame was going to be stiffened up quite a bit.

I had worried on how to fasten the box to the bed because I couldn't see much structural integrity between the two, but I can see that bringing the outside plywood down over the sides of the frame will make it rock solid.

I am going to use the 2 X 2 tube and my real light 4" x 2" I beam for cross members. I'll lay the I beams sideways and fill with pine lumber. What ever the thickness needs to be I can plane it with my wood planer.

I have some rough lumber, oak, walnut, yellow poplar that I have been drying for some time now. I sawed this on my bandsaw mill a few years ago.

I am seriously thinking of a woody, triming it with my own lumber and using epoxy and clear coat for a finish.

Just haven't settled on a final design and size yet. I'll be watching everyone else to pick up tips and ideas.

Dave

[madjack]

Dave, if you are gonna use the 4x2 turned sideways for crossmembers be sure and drill several holes init for drainage...don't leave anywhere for water to sit and cause rot....
madjack

[davefullmer]

That's good advice, Madjack, I hadn't really thought of that.

One thing I won't use is any chip board, press board or sawdust board. I hate that stuff.

I'm still working through my head sizes. I don't want huge, but I don't want cramped either. Neither my wife or I can handle cramped any more,

Gotta get a CAD program set up so I can stretch the Benroy and see how it looks.

Dave

[Gerdo]

Mine is a stretched BenRoy. It is 5'Wx4'9"Hx11'L. The wheels are inset. I love the size. I didn't want to be claustriphophic so I don't have any cabinets over my feet. Just wide open space, except for two little shelves, and a queen size bed to boot.

[davefullmer]

Gerdo,

I like it. What would another foot do to it? I was thinking that because of plywood coming in 8 foot lengths that it would make sense to build it 12 foot.

I like your inset wheels. I went through your gallery and saw lots of stuff that I want to steal from you. One of the things I saw was your fenders welded right to the frame. That's a good looking detail on your finished Tear.

I have lots of questions that the pictures made me think of. Do you have a build thread? Probably questions would be answered there.

Your signature indicates you feel like you made your Tear too heavy. Do you really feel that way? What I see looks like sound design. Also, if you are pulling something else behind it, you would need a heavy frame, wouldn't you?

I would be doing the opposite. At times I would load my '37 Allis Chalmers WC on a car hauler and pull the Tear behind it when I go to a tractor show some distance.

Also, because of this thing about the antique tractors, I won't be downsizing on a Tow Vehicle. In fact, I would be more comfortable using a one ton Dually.

Thanks for sharing everyone.

Dave