C shaped steel for frame

[sdakotadoug]

I see alot of talk about angle iron commercial frames and square tube custom frames, but thus far have seen nothing about the "C" or "U" channel frames. I see alot of these on commercial boat trailer frames. What are the pros and cons of the C channel? Thanks Doug

[madjack]

I used 1x2x3/16 C channel for my frame and am very happy with it...would do it again...if I did it again...I did use 2x3/16 tube with C channel bracing for the tongue..................
madjack

[Steve_Cox]

Next custom frame I build will be with channel iron. One thing to note is if you use bolts with nuts the inner and outer surfaces on the top and bottom of the channel are not parallel and need beveled washers under the nuts to put an even load on the bolt threads.

[Dale M.]

What Steve says.....

Other than that there is no reason not to use steel channel an long as one uses a size that is up to the job expected from it....

Lots of commercial trailer use steel "channel"....

I think the strength to weight ration for tubing is better than channel though....

Dale

[angib]

Structurally, channel is good stuff. It is actually a more effficient shape than rectangular tube but, being an 'open' section, it will 'trip' (eg, twist sideways) before reaching its full strength. The second sidewall in tube doesn't add much strength, though it does keep the tube stable right up until it buckles.

To compare madjack's 1"x2"x3/16" channel with 1"x2"x3/16" rectangular tube, I reckon the tube is about 15% stronger but then it weighs 30% more, so it's not as weight-efficient as the channel.

I think channel would be picked more for its practical advantages and disadvantages:
- channel is more complex to cut joints for, at least one one side;
- channel is easier to paint and stop rusting;
- channel is better to bolt to (no risk of crushing a tube).

[BC Dave]

I was looking at some heavier duty flat decks yesterday; the heavier duty ones used C channel on the exterior rail (I didnt get a good look under as I was preoccupied by the salesman who kept destracting me grrrrrr); as above, intresting that its slightly stronger but heavier;

the 6X10 flatbed weighed in at 1500 lbs and had about 150 - 200 lbs tounge weight; with a GVW of 3500; 3500 axel and 15 in tires.

[LDK]

I have a harbor freight trailer and it's a C channel. The tongue is also but I wanted to strengthen it so I had some thin plate iron welded in the channel.

[BC Dave]

I have a harbor freight trailer and it's a C channel. The tongue is also but I wanted to strengthen it so I had some thin plate iron welded in the channel.

The Harbour freight is thinner gauge C channel compared to what Steve discussing / showing;

Harbour Freight that looks to be flat / bent; where what Steve shows looks to be cast ...

[Arne]

h/f frames have a lip on each side to the top and bottom to keep it from twisting and deforming.

I've use them on both t/d's and have never had a problem. I find the h/f frames are overkill for a t/d build, except for the tongue portion of the frame. That should be as it is and the A frame tongue is very strong.

re the cast stuff, have no idea about that.

[bobhenry]

Yet I was concerned that mine was flexing to the point I was concerned and followed Harvey's ( nobody's) lead and added a 2x2 x1/4 wall square tube to reinforce it. !







Please notice my c chanel does not have the additional fold it only has two folds not four as the picture in the previous post above shows. Those 2 additional folds would add a great deal of strength to the tongue.

[deepmud]

scavanged from a conveyor belt frame. Free!



strong? 2300 lbs of load.



Tough? 15 years, 15 thousand miles on one trip from Alaska to D.C. and back, just took it on the Denali this summer...

[Rigsby]

Im using a pre formed `c` section on my second build, All modern caravans over here in GB use it

[dh]

If you put the open side in you will have to cut a tongue on each x member. If you put it out and leav it exposed you will have a nice recess to mount marker lights. If you put it out and cover it you have a nice channel to run wires in before the walls go on. I used channle on my flat bed and have no regrets.

[dh]

A quick word on steel. HF channles are stamped from flat stock. Regular channle is extruded at the mill or "hot rolled". And I'm sure if you look for it you could find its cousin "cold rolled" which is just what it sounds like.Extruding the metal while cold gives tighter tolerances.

[sdakotadoug]

I have't checked in in awhile. Lots of new information. It all adds to the gray matter for when I actually get around to starting my build. Doug