Lippert frames

Ralph Cramden wrote:


Here is why I think you're mistaken and the 10" high frame rail in your picture is a machine welded piece, and not a conventional hot rolled member. They make hot rolled H shapes (we call them a wide flange or W) or I shapes (A Jr / I, or S), only in specific readily availible sizes and weights. Going by your picture the flange width is roughly 2-1/2" wide. I determined that by comparison to the two fittings installed on the black tank. One is 1-1/2", the other 3".

There is no H or I which is hot rolled that a company like Lippert could buy from a hot mill, that would be those dimensions in a 10" height. It simply does not exist unless its a custom hot rolled shape and cost would not typically allow that.

In your picture you have a 10" height, a 2-1/2" flange width, and a 1/4" thickness both at flange and web based on the measurements you took.

Here is what you can get from a hot mill.

There are a couple dozen made with a 10" size in a wide flange, but none including the lightest which is a W10X12(lbs per ft), has a flange width smaller than 3.960 inches. Then they go up from there. The only size in a wide flange that has anywhere close to 1/4" average thickness at both flange and web is a W10X15, with a 4.00 flange width. The web is .230 and the flange is .269

There are only two readily available sizes in a Jr/I/S with a 10" height.
S10X25.4 or 10.000X4.661, The flange is 4.661 wide, and the thicknesses are flange .491 / web .311
S10X35 or 10.000X4.944, The flange is 4.944 wide, and the thicknesses are flange .491 / web .594

That's why I think your main rail is an engineered / fabricated / machine welded shape. That is unless Lippert is having hot rolled shapes custom made at great expense, or own a hot mill and making their own. Not sure why they would want to. The size is not available unless its fabricated. Maybe I'm wrong.

Hi Ralph,

There was a period of time when Lippert was able to get hot rolled MH beams. They might still be able to, I don't know. I have one made in Nov. 2003 and Hunting Dog's has one too although his is a little heavier than mine.

I cannot find these thin H shapes "yet" in any hand book, but they do make them for the Manufactured Housing market. They call them MH beams or thin I beam. Here is one mill that makes them. So far that is the only mill I can find them on the web that does. I'm sure there are more, just I have not found them.
http://www.swvainc.com/housing.html

You will notice they offer a 10 x 8#/ft and a 10 x 9#/ft which I have and it has an area moment of inertia of 35.5 in.^4th.

Huntingdog's frame is closer to a 10" x 13.2#/foot with an area moment of inertia of 50.6 in.^4th. His vintage is stronger and the one he ended up with was a good one. I wish mine was that heavy, close to 42% stronger given the same steel. He has a higher GVWR on his camper then mine too. Mine is only 10,000#. Dog's is 11,500#

Here are some rusted pics of mine. I have since cleaned that rust off and painted it after my repair and these are all I had on my web server that sort of showed the radius. They are rolled.






Here is a closer one of the radius


These beams are for sure thin. They do make them from HSLC steel in the 50ksi yield range. In order to help them not deflect, they are welding beads on the top flange to heat/shrink in some positive camber at the rear hanger area to help the overhung loads keep the beam straighter. This have been ongoing in the industry for a long time.

If you ever find a handbook of these, please let me know.

To the topic of Lippert frames, in my case Sunline used them as a subcontractor. They had an east coast plant near their factory and they use to make products for Skyline too I think back in the day. And as far as subcontractors go, if the firm hiring them accepts poor quality that is problem 1. In my case my frame was not made that bad although I had issues they could not weld hangers on in the correct location. They just plain screwed up. If all the big RV manufacturers are accepting poor quality they are paying for, in my book they are as bad as the ones who made it.

Hope this helps

John