Fabbing some Long Arms. Questions.

Here's my idea. I want a long arm set up and instead of shelling out money I really don't have I've decided to build it myslef. I've read several articles on the subject and so I have a basic understanding on what's invovled. However this is my first real fabrication project and I need alittle assistance. I'd be building them with an experienced fabricator and he'll be welding them for me and making sure I don't f-up too bad. :nono:

(Photos from old_man's write up: http://www.4x4getaways.com/LongArms.htm )

I want a set up similar to this:

Not sure if all long arms have the upper arms mounted on them, but that's how i'd like to do things.

So for the joints I've decided to use RE Super Flex joints on the frame mounts and on the upper arm. For the axle side of the long arm i'll be using plain ole' rubber.

Now for the questions...
+ Is stainless steel weldable? :dunce:
+ What size tubing should I use? 1.75" OD with a wall thickness of .120" Chromoly?
+ What size (adjusting) bolts should I get for the arms? Would Grade 8 bolts be suffice? These will be the bolts welded onto the superflex joints and screwed into the long arms:

+ I'd like to have the arms mount on the transfercase crossmember, so I was thinking of either building my own or buying the rusty's HD crossmember and toughin' it up and welding on the mounts for the long arms. (I know Rusty's stuff is crap, but I firgure if this peice is weak i'll be able to add more metal to it...or not? :wow: )

Thanks Guys. atriot:

And thanks old_man for the write up, it's the only reason I want to fab up my own arms! You got me hooked man... :viking:

you know rusty's is crap?

y2kxj said:

you know rusty's is crap?

Click to expand...

I suppose it's not crap, but it breaks.

everything breaks sometimes. You get what you pay for and he doesn't charge much for anything. Right there you know you aren't getting the best but it works for alot of people. You saw a picture of a broken part on another post and made your decision. It's not wrong to have an opinion just don't bash it before you try it.

How can you not make a judgement based on that picture. And not only that picture. There have been several that have floated around on this board and others, all showing failures. If Rusty's was even half way decent they'd atleast clean up their act and solve their problems, but even that seems to be hard for them to accomplish. :dunce:

I've order things from Rusty's before and i've always been content with it, but I wouldn't trust them for any suspension components. :skull1:

Oh and cheap? How can cheap work for most people? What's the point of saving a few bucks when your putting your live in your own hands. I guess you could get away with cheap suspension components as long as you never wheel your junk. But where's the fun in that?

Anywho, does anyone have any advice on the long arms?

I never said it works for most people. I said it works for alot of people. I wheel my "junk" and it works fine. You're talking about buying a crossmember from him (which is not a suspension component) and then call it junk? I hate to keep this petty crap up but you baffle me.

Don't know if I'd use hardened bolt if you're gonna weld to them. Could make them brittle.


Dan

You dont want or need a Super-flex joint at the axle!I used 1-1/4" Chromoly allthread!

I've welded on these large diameter grade 8 bolts for years with no problem. I use a mig and work the puddle to fill the crack. I'm an engineer as well as a tool and die maker. I worried about the problems about 20 years ago, but I've never had a problem so I quit worrying. I have bashed the hell out of them with no ill effects.

with radius arms...you will have no flex from the axle side joints...just bind. You will want to use rubber or polyurethane there. RE joints are worthless there as there is no misalignment.

For link material...1.75 .120 wall is no good alone. I will be using 1.5 .25 wall sleeved with the 1.75. You want at LEAST .25 wall for links. And when they get as long as some make them...you need thicker.

For threaded part, I am welding the 1.5" .25 wall onto the RE joints, and using 1" B7 threaded rod inside of that and welded in. Then using weld in bungs onto the main part of the arm.

I don't like the bolt straight onto the joint because there is not as much weld area as there is on 1.5" OD tube.

_nicko_

I agree with gearwhine on the surface area,thats why I sleeved the threads with a piece of 1-3/4" x .188" wall!
Btw:when I built mine I found the best write-up I've seen(still) by ZPD,I found the link from a 1.5 yr old post but it doesnt seem to work,maybe He'll chime in!
http://www.xjworld.4wdriver.com/longarm.htm

Hi,

Another quesstion on fabbing LA for my XJ. Would using 2 Johnny Joints be better? Meaning one on the frame mount of the lower and one more on the upper arm to axle?

Thanks

Did you read the above posts?The answer is NO!

RCP Phx said:

I agree with gearwhine on the surface area,thats why I sleeved the threads with a piece of 1-3/4" x .188" wall!
Btw:when I built mine I found the best write-up I've seen(still) by ZPD,I found the link from a 1.5 yr old post but it doesnt seem to work,maybe He'll chime in!
http://www.xjworld.4wdriver.com/longarm.htm

Click to expand...

hmmm, That's wierd, it worked last week. oh well
I used 2" OD DOM with a 1/4" wall. I also used acme thread (1 1/8" IIRC) welded directly to the currie johnny joints. I also welded in two acme nuts (one was a coupler and the other was just a nut) inside of the DOM. I did rossette welds as well as bung welds. I turned the two nuts against themselves to almost eliminate backlash. Because of this I don't need a jam nut. I have had zero problems with my set up. I have had it on for almost 3 years and although I haven't abused it as often as I would have liked to, they have been abused.
I personally wouldn't use stainless or chromoly. You really have to know what you are doing to be able to weld that stuff. And although Chomoly is cool, i would think that .25" wall DOM would be stronger than .12" chromoly (but I don't have my metalurgy book in front of me) :lecture:
good luck