Hothondaguy

Curious, we have a 1991 4runner and we removed the factory running boards and we would like to build our own Sliders with Steps, we are looking at 2x3 steel tubing for the main protection but would like to know if 1/8" is ok, we are only moderately using this for off-road.

E-ROC

nope. use .120 wall. you will thank yourself for doing it right the first time.

xxxtreme22r

in other words 1/4" thick. assuming he means SCH 120 not .120" Because .120 would be thinner than 1/8 which is .125.

BigBluePile

iTrader: (3)

Lolz....

meatmonkey

I've cut out the rusted rockers from my 92 4runner and replaced them with 2x4 .120 wall thickness tubing that I stitch welded back to the body. I've hammered it pretty hard for about a year and have a few small dents in it but nothing major. Even before I tied the rockers into the frame I could high-lift jack the truck up from them without issue.

Unless you are absolulutely abusing it all the time then .120 wall should be fine. If you are trying to kill the truck then maybe double up the lower edge with some angle iron to help reinforce it.

IMO .25 wall is overkill and unnecessary weight.

xxxtreme22r

http://www.4x4wire.com/toyota/tech/sliders/

seems that most of these guys that are not using DOM/HREW .120 are using 3/16". One even mentioning that the 1/8" mounting plates were not enough especially not being gusseted. All-Pro to be exact.

So does this mean DOM/HREW tubing is stronger than box steel?

Magnusian

HREW: Hot Rolled Electrically Welded.

DOM: Drawn-Over-Mandrel, think HREW only they force it over a mandrel. This stuff seems to be considered "better" than HREW because it ends up being "work hardened" in a sense. Whether or not it actually is better depends on how you're using and abusing it. You probably wouldn't want to do something like make a truck frame out of DOM through

In either case these refer only to the tubing, the brackets will be made out of either hot or cold-rolled, and I doubt it really matters which in this case, though the cold will be a lot more uniform in thickness and probably harder.

If they are using 3/16" thick wall steel tubing they haven't made themselves out of sheet metal, then it has to be HREW, if it was DOM they'd say it was, and if it was extruded seamless they'd be BRAGGING.

BigBluePile

iTrader: (3)

Pretty sure AOR bumpers are .120" tube and my sliders are .120" dual tube and I'm pretty sure my rear bumper is .125" plate....wierd....

xxxtreme22r

I know the difference between DOM/HREW, maybe I should rephrase my question. Is round tubing considered stronger than square tubing since it seems people are using slightly thicker walled square tubing then they are round tubing. I always thought square is considered to be stronger than round. Think I-beam over pillar.

What has thrown me a little off is the 2nd post saying nope use .120 wall. Which might as well be the same as 1/8". Like I had replied, NPS 2 SCH 120 is .250 (1/4") thick. What I am seeing so far people are referring to .120 in real terms not SCH terms. Which is understandable. But not when someone says No 1/8" thick is not enough do it right the first time and use .120 wall.

Magnusian

To really understand why, you need to understand the way mechanical stresses act upon objects of different shape, thickness, size, and assembly. I wouldn't know where to begin teaching someone about it, but if you are really interested find a mechanical engineer or take a material science/physics course at your local college.

I'll try to tie in some examples off our vehicles.

A round tube would hold up more to torsional ("twisting") stresses, think about most drive-shafts, are they round or square, and when people make custom square ones they seem to use a lot thicker material to make up for the difference in torsional strength*. Round tube would be more prone to kinking and bending than square, where square would be more prone to twisting. You have to use thicker square material to compete with the same torsional loads, this is why our t-bars are round and not square else they would be a lot thicker and weigh a lot more.

Square tube is a lot "stiffer" (lateral? compressive?) than round, and while it would probably twist like a top under tosional loads that round of the same thickness. Have you ever noticed how much harder it is to bend square tubing than round? Our frames are effectively rectangular tubing, probably for this very reason.

I'm not a mechanical engineer so I can't give you a real in-depth reason as to why this is, but if anyone else is chime in! Material science was not a class I felt was all that important to my field of engineering so I kinda slept through it... I don't think I'm 100% right on things either so it would probably be a good idea to confirm it first.

If they are using thicker square than round, then it's likely because sliders see more torsional loads (this doesn't make sense but I haven't seen sliders in action in person so I really don't know) than anything else. If that's the case I would go with round over square to take advantage of the lower weight of round tube though I probably would go with 3/16" wall thickness.

The reality is neither is truly better than the other, and to cope with the stresses that one is good at, the other has to be made out of thicker material. If you want to keep round from bending, make it thicker, if you want to keep square from twisting, make it thicker.

*Of course all the drive shafts for my tractor and implements are kinda a bloated tri-angular shape, which is probably done as a compromise between the two, sacrificing some torsional strength for more rigidity. A material like this might be ideal for sliders if people are worried about the tube being subjected to a variety of stresses.

Also, yeah, I don't get the second post in this thread, I'm thinking the guy might have been thinking 1/16" when he read 1/8".

xxxtreme22r

Makes sense to me. Materials class in nuclear school was a help in understanding that. But that almost solidifies what I was thinking about tube versus round as sliders. I don't see how sliders see torsional stress at all. But yet most are made out of tube as well as roll cages. But a roll cage I can see torsional stress, but not due to a roll over, but because of chassis flex.

Magnusian

Yeah, someone else who knows will have to chime in on what stresses sliders see the most, I don't really see how they'd be subjected a lot of torsional stress either.

Speaking of cages... hush, I don't need -that- idea stuck in my head under after my truck has plates.

Hothondaguy

i was looking at 1/8" 2x3 rectangle tubing for the main slider part and then some smaller tubing for the steps, we are not heavy off-roaders and this will be my dads first attempt and building a set.

waskillywabbit

iTrader: (-1)

More than adequate. have some like that on my Tacoma project thread if you want to go take a look at them.

:wabbit2:

mustfjos000

The reason people use round tubing vs square tubing to build anything ,weather its rock sliders or roll cages, there are many factors to consider. Weight, strength, type of force that will be applied, the way it takes damage, corrosion or rust, and the look of it. Roll cages are made out of round tubing more for weight if you built a square tubing roll cage of the same strength it would use less steel but weight more and if you rolled it over more of the damage would be on the site of impact were as round tubing would displace the damage through the entire structure just like the interior of the doors on new cars and trucks they use a single or double round bar system that is ment to spread the load over the entire door so it doesn't V in it'll U in per say.


When you are designing anything follow a process. what is the purpose of it, what kind of damage will it take, how much should it weigh, how much should it cost, and how do you want it to look. you can use a single square bar with brackets that's the simplest, or use 2 round tubes parallel with a triangle pattern in between and brackets and get the same results you'll have different costs and weights.


Like mentioned before there is a lot more to it you have trig, material analysis, structural rigidity, geometry, and so much more. I went to school for mechanical engineering and fluid power systems and theres so much info and so many possibilities.