Is "C" channel a better material for the main fram

[Esteban]

Just thinking out loud here about alternative ways to build a trailer frame.

My 5' x 10' frame was made from 2" x 2" x 1/8" square tube, with 2" x 2" x 1/8" "L" angles on two foot centers for cross supports, and a 48" long A-frame tongue made from 2" x 3" x 1/8" rectangular tube. I'm happy with my frame.

However, if I were to have a new frame made I'd be very tempted to make the main frame from 1-1/2" x 2-1/2" x 1/8" C shaped channel instead of 2" x 2" square tube, and would probably use the "C" channel for the cross supports too. The tongue could remain the same.

Why, you may ask? Because it'd weigh less, it would be easier to attach the floor, and it'd probably cost less. It would also be easier to attach running lights because you could easily attach them to the "C" channel.

Steel weights per Andrew's tongue strength information in the Design Library:
2" x 3" x 1/8" rectangular tube weighs 3.90 lbs. per foot. Good for an A-frame tongue.
2" x 2" x 1/8" square tube weighs 3.07 lbs. per foot.
1-1/2" x 2-1/2" x 1/8" "C "channel weighs 2.23 lbs. per foot.
2" x 2" x 1/8" "L" angle weighs 1.65 lbs. per foot.

The weight, exclusive of the tongue, of three alternative ways of building a 5' x 10' frame assuming 50' (two 10' sides, one 5' front, one 5' rear, four 5' cross supports) of steel is used would be:

1) 125.10 lbs. using 2" x 2" x 1/8" square tube for the main frame with 2" x 2" x 1/8" "L" angle cross supports. (30 x 3.07 = 92.10) plus (20 x 1.65 = 33) 92.10 + 33 = 125.10 total lbs.

2) 111.50 lbs. using all 1-1/2" x 2-1/2" x 1/8" "C" channel for the main frame and the cross supports too. 50 x 2.23 = 111.50 total lbs.

3) 99.90 lbs. using 1-1/2" x 2-1/2" x 1/8" "C" channel main frame with 2" x 2" x 1/8" "L" angle cross supports. (30 x 2.23 = 66.90) plus (20 x 1.65 =33) 66.90 + 33 = 99.90 total lbs.

Either of the lighter frames would be easier to attach the floor to, than square tube, and could make attaching side walls and running lights easier too. They each eliminate most of the extra attachment tabs. I got inspired to figure them out after thinking about the Northern Tool trailers that some people use and alter.

Hope this makes sense.

[halfdome, Danny]

Steve, I'm currently cutting out parts for another TD chassis for a 5' x 10'. I have the following:
2 rails 1/8" x 1 1/2" x 2 1/2" x 96" = 43.2 lbs
4 cross members 1/8" x 1 1/2" x 2 1/2"x 54 1/2" = 50.4 lbs
1 tow bar 1/8" x 2 1/2" x 2 1/2" x 54 1/2" = 21.6 lbs
1 piece 3/16" x 2 1/2" x 2 1/2" x 48" angle for body mounts & gussets = 10 lbs
2 pcs for the tongue "Y" 1/8" x 1 1/2" x 2 1/2" x 55 1/4" = 26 lbs
Total not including the axle, coupler & bike rack receiver = 151.2 lbs
I don't know the weights for stabilizer jacks etc but this is the basic weight.
They were all weighed with me holding each piece on a digital bathroom scale & I feel the weights are accurate.
Some builders have used bed frame for their chassis so I guess it up to the individual builder what his comfort zone is. I myself wouldn't feel comfortable with anything less. As far as attaching wires, a hole drilled is a hole drilled no matter what you use. I hope this is of some help, Danny

[Esteban]

So Danny you're starting Number Three, are you? Seems you're being careful to consider weight. Will enjoy learning how you continue to improve your trailers.

On my frame I don't want any penetrations into the tubing to protect them from internal rusting. All of of the bolt holes to hold the floor to the frame were drilled through the corner gussets, L angle cross supports, and a couple of extra welded on tabs.

My walls will cover the trailer frame. That makes it a bit tricky to route wires to side clearance lights, and a below the side doors "porch light", because I don't want to drill through the square tube. If the main frame was made from "C" channel instead it'd be much easier to drill holes as needed to attach the floor or to run wires without as much concern about rust.

"C" channel seems to offer many advantages over tubing for a trailer frame. It's lighter, should cost le$$, nearly are strong, eliminates the need/complexity of welding on almost all attachment tabs, would make bolting on the floor easier, as well as making it much easier to run wires as needed.

The weight saved by using "C" channel for a frame might be similar to what a cast iron oven, or some other camping goody, weighs. Or more malt beverage carrying capacity.

I'd probably only use steel tube for the tongue on the Next One, should there be a Next One. Thinking and dreaming ahead as well as offering ideas that might improve others peoples teardrop building.

There may be another advantage to using "C" channel for the main frame. You can bolt a torsion axle, like a Dexter #9, directly to it. If you ever needed to move the axle to better balance the trailer it'd be easy to do.

[Arne]

All/most h/f trailers use c channel. I've never had a problem. I think the heavier is 3" tall and 1-3/4 wide, the smaller, 2.5 tall....

no. 1 did have a single tongue, but no. 2 uses the smaller for the V tongue and the heavier for the perimeter.... works great and as you say, easy to bolt on.

take a look at the link below to see frame. You can see on the V, about 2/3rds back, I mated the small to the larger with an overlap welded joint.

Most frames are built heavier than needed

[halfdome, Danny]

Steve, yeah I've got to have a winter project .

Whenever I have to attach the corrugated wire conduit with a slit I just paint over the screw with Rustoleum. My walls hang 1" below the chassis so there is no need to run a wire through any steel just under it. I've tossed around the idea to use Lite Ply available in Seattle but for $86.80 a sheet for the 18mm x 4 x 8 it may not happen. Northamply.com Danny

[madjack]

On the CamoGatorTear, I used 1x2x3/16 "C" channel, the same material for cross braces and a 2x1/4 tube tongue with the C for "Y" braces...sure seems plenty strong to me...corners are beveled, cross braces were fitted up flush on the inside, leaving an opening to run wiring inside of frame...I really liked it and would use it on any other build I might do...cheaper than tube and flat surfaces on 3 sides for mounting???
madjack

[Esteban]

cheaper than tube and flat surfaces on 3 sides for mounting

My "pick up truck" is a Harbor Freight trailer made of "C" channel. It got me to consider potential advantages of using "C" channel. There seem to be many of them. Its 3 mounting surfaces, like madjack articulates, really would be a convenience and a construction time saver.

At the beginning I was tempted to use some Okoume plywood to save weight. Its high co$t overruled that idea.

The teardrop trailer I'm building has a 5' 3" wide by 10' long floor and about a 11' long body so I carefully consider weight. It's not too hard to save weight if you pay attention.

Like Danny I have a digital bathroom scale in the garage/shop. Use it to weigh components as I go along. Let's see...the 31" W x 39" H door frames with 1/4" outer plywood skin each weigh about 11.2 lbs. They became a little heavier when I added more blocking to be able to attach cloth storage pouches on the inside of each door. Seems worth it.

Off topic about a trailer frame. The amount and complexity of cabinets is a real weight concern. Using a scale helps to decide if "nice to haves" make the cut or not.

[halfdome, Danny]

Off topic about a trailer frame. The amount and complexity of cabinets is a real weight concern. Using a scale helps to decide if "nice to haves" make the cut or not.

It's your thread . Believe it or not the 4 solid Red Oak raised panel doors in my cabin weigh an astonishing 8 lbs well worth it in my opinion. I usually don't bother with weighing components as I don't have much control with engineered plywood etc. Just curious how much the chassis will be. Danny

[Esteban]

OK, this is beginning to be a stream of consciousness thread thinking more about the 3 mounting surfaces with "C" channel.

In the rear corners the top of the "C" could be the surface to bolt the floor to...no extra gusset required. The lower surface of the "C" could then be the mounting surface for leveling jacks. Easy. Saves work, materials, weight, cost and time. Maybe a few more brain cells will prosper too.

Thanks to Ron Dickey, I recently met a nice couple, Richard and Loraine, who plan to build a teardrop. Richard and Loraine met Ron while shopping at Home Depot...Ron's workplace. Ron's a good recruiter into the tear dropping club/obsesion. He sent them over to meet me to get ideas. The more I think about it the more advantages I see to use "C" channel for the trailer frame. Think I'll pass on these ideas for them to consider.

It's your thread...Wink . Believe it or not the 4 solid Red Oak raised panel doors in my cabin weigh an astonishing 8 lbs...

Danny is that per door, or for all of them?

[halfdome, Danny]

It's your thread...Wink . Believe it or not the 4 solid Red Oak raised panel doors in my cabin weigh an astonishing 8 lbs...

Danny is that per door, or for all of them?

Steve, that's for all four doors or 2 lbs each. In my opinion there is no substitute for quality of materials.

[angib]

Assorted thoughts:

If you want to save weight, I would question why you need so many cross-members - or indeed any cross-members at all, except for the front one. Things like the galley bulkhead are stronger than any cross-member that is underneath it.

If using a single tongue (on its own, or with side braces) of course a second cross-member is needed. Indeed the strength of the tongue may be limited by that cross-member - several frames have been shown on this forum that will fail at the second cross-member, not at the tongue.

Madjack - does your "flush on the inside" joint mean that only the flanges of the side rail are welded to the cross-member? If so, this is a very weak joint, but probably strong enough - the cross-members aren't carrying any serious load so not much of a joint is required.

And finally, can anyone suggest a decent steel sales web site that shows available channels? I had a hard disc crash and the one thing not backed up was my bookmarks.

Andrew

[bg]

Andrew,

This is a supplier I've used

http://www.eaglesteel.com/catalog.php?cPath=21_24

[madjack]

SteveB...that is exactly the way we used the C channel....

Andrew...yes, all these crossmembers were welded both on the outside and inside...their only real purpose is to give support to the single sheet ply floor...the front and rear crossmembers are fitted to the side rails with beveled corners...also welded inside and out...the side "Y" braces on the tongue come back under the frame to about the 30" mark.........
madjack

[brian_bp]

The specified C-channel is certainly a bit lighter than the same thicknesss of 2" square box... because it is narrower and missing one side. If the loss in strength is acceptable, then maybe a thinner-wall box or a narrower box (can you get 1.5"x2" box section in 1/8" wall?) should be considered as well.

There's no question that for bolted connections channel is easier to work with. I just wouldn't get carried away perforating the stuff to attach structure: except near the ends (where the stress is lower), the top and bottom flanges are not suitable bolting locations, because the holes remove much of the strength of the channel. Look at a truck frame of C-channel: the holes are in the vertical side, not the flanges. That makes directly bolting a Torflex axle and moving it around between a bunch of holes a bad idea structurally, although a flat bracket could be fabricated which bolts to the side of the channel, and to the side-mount holes on the Torflex brackets, then the side of the channel could be drilled like swiss cheese for axle placement options without structural concerns.