Roll Cage Tie In Suggestions

[tinman565]

Its simple. If you run the tubing THRU the box....it will be less likely to bend, rip, or tear (way stronger as you now have BOTH sides holding the tube). Your way will work, but you are not gaining much strength by welding an inner piece to the SAME SIDE as the piece your putting over it. Your way can still tear or shear from that single side. You asked for a strength suggestion...and numerous people have told you how to make it super strong. You are obviously set with your idea. It will work...and probably be fine. What we are telling you is that of a few different ways to make this stronger, your way is not the number one choice for strength by people who do this stuff everyday. Go with your idea....your gonna anyway. Move on to the next part of the project, and get it done.

 

[Shield Arc]

What about using some gussets like this? After I drew it, I remembered you may not be able to use the top one. Maybe just a gusset on the bottom, and the two sides? Using gussets is an easy way to pick up more weld volume.

 

[Artisan]

What about using some gussets like this? After I drew it, I remembered you may not be able to use the top one. Maybe just a gusset on the bottom, and the two sides? Using gussets is an easy way to pick up more weld volume.

Can't do it on the top because the Anchor touches the bottom of the ROPS.
Possible 2 on a 45 at the bottom would tie it in, that's thinking outside the box!
I just walked out there and laid out the exact Center to Center of the short
tubes on on the Anchor itself and if I were to thru drill it, it'll start to daylight
on the rear side due to the radiused end, plus I used 1/2" x .25" flat bar to
make the radius so it would be difficult to drill less a mill w/ one plunge cut.
I appreciate the ideas...almost sounds like tinman is annoyed, certainly not
my intensions...I appreciate the input... and I will think it to death. :scratchchin:

 

[handirifle]

I don't think I am sure that you understand, what I am really meaning, because if you meant to say what I am really understanding you to mean, we wouldn't even be having this conversation. That sound about right?:laughing:

Seems like I've had this conversation before.

 

[rambler]

FWIW;

Prior to posting this post I thought about drilling one side and both sides.
I decided against it for this reason. I am taking a VERY strong member
and making it REALLY week by drilling all those holes! Now I stick my
tube in it and expect it to take up all the slack.

I'm a simple dirt farmer, but seems in any construction, there is a weak link.

If yousurface mount the tube to the square beam, that will be the weak area.

If you drill through and weld both sides, it will appear stronger, but actually you'll have about the same ring of melted metal in about the same place, sowon't be much different?

If you drill through and only well the far side, couple small tack welds on the inner tube wall, then the pipe wil be at max strength and the anchor point and the flex point will be 2 different points, probably strongest.

Adding gussets as mentioned to either design will boost the strength greatly, placing the shear & flex farther away from any flush connection.

Designing a roll cage implies a lot of liability that it actually works if/when needed - without any real testing for a one-off deal. I would guess that is why you got so many questions on how it's really working.

This whole deal is going to be clamped to the existing roll bar at the back ofthe tractor, and then something will extend down from your square bar to make front A-frame cage?

--->Paul

 

[Artisan]

Paul look at post #12 in this thread, it is a rough drawing
of what I think I will do. Thanx for the input!

 

[Shield Arc]

Personally I'd go with the gussets. But I'm real new to this welding fabrication thingie bob.
The reason I'd go with gussets is because of the HAZ on such thin material, I'd use no thicker than 1/4-inch thick plate for the gussets, and skip weld them also, this will spread the HAZ out more.
Like I said, the HAZ is my biggest concern!

 

[Artisan]

HAZ = ?

 

[tinman565]

Haz = Heat affected zone (keep welding in the same general area, and it actually starts getting WEAKER) thats why I recommended not doing it that way with the thickness of material your dealing with.

And I'm not annoyed....but he mentioned gussets in his first or second post...now you say he's thinking outside the box ? Point being, that gussets were mentioned long ago...but your stuck on your idea...and cant/wont absorb suggestions unless they deal with your tube inside a tube weld design.

 

[jim_wilson]

How strong does it have to be for .120 wall tube?
Only thing I can think of is drill holes and insert the round tubes through the box tube, and weld both sides. Or use gussets to pick up more weld volume on the one side.

That's one of the typical methods recommended for building a rollcage in an automobile. If you are attaching a round rollcage tube to say a square tube section of the frame - drill two holes the same diameter of the tube - insert the tube thru the holes - and then weld the round tube - on both sides of where it goes thru the square tube section of the frame.

If you just weld the round tube on top of the other square tube - you risk it shearing off - or punching thru if it gets hit with a big enough load.

Where the round tube comes out and extends down - reinforce with gussets to prevent sideways bending forces from shearing the tube off at the weld joint.

 

[Artisan]

So is there a way to counter HAZ?
Could this whole piece be heat treated to X degrees for X time to
settle things down or whatever the process is?

Additionally, because of the ramifications of failure
I will have a professional welder do the job, even though
I own 3 millers. I do not have a TIG machine. My welder
is incredible. I mean his work is just off the chain
beautiful. he has contracts everything from nitro RC expansion chambers
for RC toys, out of Aluminun to 10" Flanges and he welds those
babies up and it it looks like a robot did it.

Greg Sexton, Ontario California. GREAT Welder.

 

[Shield Arc]

What do you think about using 1 3/4" cold rolled round stock instead of that 1 3/4" x .120 wall round tube? Then there will be no need to worry about the HAZ. That .120 wall thickness has had me concerned from the beginning!

Weldment Preheating & Interpass Temperature-- MWSCO Tech Support

 

[Artisan]

What do you think about using 1 3/4" cold rolled round stock instead of that 1 3/4" x .120 wall round tube? Then there will be no need to worry about the HAZ. That .120 wall thickness has had me concerned from the beginning!

Weldment Preheating & Interpass Temperature-- MWSCO Tech Support

A couple three years ago when I bought my tubing bender I did research
on what the average Joe uses to make a cage. Indeed 1-3/4" x .120 wall
was and still is the norm...

I think NASCAR demands .095 wall, but CroMoly

I appreciate ALL the input from everyone, Thank You.

 

[tinman565]

You guys are turning this into a major project...lol. Its basically a garden tractor. He's not gonna jump it. Jeeeezus...lol.

By the way...why dont you just let your welder handle it ? You've praised his ability. Are you trying to impress him ? Now your talking about heat treating this ? LMAO !!!! Still...back to your idea I see. I'm surprised your not making this out of 8" I-beam. Heat treating...lol. Say...why not stop by your local hospital and see if you can make an appointment to get the welds X-RAYED ????

Please post pics of this NASCAR approved cage when its completed sir. Tractor should be worth at LEAST $5000 more when your done (rolling my eyes).

Oh...and just in case your wondering about my experience: My parents owned a machine/fabrication shop (been doing this stuff most of my life). I then went into the Air Force, and worked on the flight line (FMS) as a welder. I worked 8 years as a JOURNEYMAN welder in maintenance at a Dunlop Tire plant. I have worked the past 18 years as the JOURNEYMAN LEAD WELDER/GROUP LEADER in the tool room at General Motors.
Not that any of this matters...but just in case you questioned my credentials.

Should look something like this...by the time your done.

 

[Shield Arc]

Now I was just talking about using the 1 3/4-inch round stock for the short little nipples, not the entire cage.

I had the opportunity to spend a Saturday with some NASCAR weldors at Miller's testing facility in Chicago, those boys forgot more about welding than you and I will ever know!

 

[Artisan]

NASCAR? Interesting... I would like to visit that testing facility.
I wish I could find a Miller TIG machine cheap. I have a Miller Vintage,
a 130 XP, a Spectrum 375 and a ThunderBolt XL. I got the Thunderbolt XL
for 100bux last year, have not used it yet, I will have need someday I am
sure. A MIG Gun is not long and skinny!
Do you have a TIG SA?

 

[swick1]

Don't forget to weld in some crack arrestors! (p. 181) ;-)

http://www.shipstructure.org/pdf/81symp14.pdf

Good luck. I think you'll be fine with just tying the top tubing into that square bar by chamfering the edge from the outside and putting in 3 weld beads, but that's assuming you aren't going to roll it off a cliff.

If you want to be really paranoid, read these papers:
weld unzipping - Google Search

 

[Shield Arc]

Do you have a TIG SA?

Yes, the Miller Dynasty, and Miller 330A/BP in my signature are both Tig machines. I also have a Tig rig I can run off my engine drives if needed. The two Millers are the only machines I have that can do AC aluminum. The 330A/BP was giving me trouble, eating high frequency capacitors like candy! So I retired it to the back of the barn, and bought the Dynasty. One of the NASCAR weldors at Miller's testing facility was running a Dynasty 300, he let me try it, and worked with me for a few hours. I fell in love with the Dynasty, soon as I got home I ordered one.

 

[Artisan]

Ah yes....Crack Arrestors! Maybe I will take pinheadgirls demented
suggestion and do that with "8" I-beam" as she suggests as she would do.

I will read that PDF later just to learn. Gawd I wish my mommie and daddie
would give me a career. I had to earn mine. Must be nice silver spoons and all.
Must be nice ot be so holy that you can ridicule and rip into another mans
aspirations and dreams, right or wrong, the rightous ones, are "idiots".

 

[swick1]

Just hit the ignore button for posters you don't like. I think you are doing a great job and in my opinion the rops is going to be the weak point. Be sure to think before you add too many gussets. Sometimes they can create local stress concentrations in excess of what would happen by just letting it bend. I have a good article on it I'll try to find.