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Sat Jul 14, 2018 6:52 am

Howdy again all!

Need some advice on a roll cage for my buggy in build.

Roll cage recommendations....

Tubing bender?

Tubing notcher?

Mild steel, or chrome molly?

Tube thickness?

Tube diameter?

Recommend welding components? I have a light duty cycle 110V MIG/TIG welder.

Thanks,

Donnie

Sat Jul 14, 2018 7:14 am

Basically the tools like benders and notchers are you choice for the job you want to do...

For the best concept of cage material is what is more important if you are going to do a build that is safe in any situation and not a "show" build (one that is pretty but useless in a incident) ...

IF you don't want to spend several hundred to a thousand (or more) in tooling, find local race car builder that will bend and notch your tubing for you....

LIGHT DUTY 120 VOLT WELDER is pretty much on ragged edge of getting good quality weld .. I personally would like to have welder with little more capabilities to ensure really good welds with proper penetration...Ultimately TIG welds be the best... Assuming competent welder...

Main tubes should be 1-5/8 inch O.D. DOM tubing with .120 wall, that will insure the actual material will pass almost all sanctioning body rules.... Attachments to body/pan really need to be at least 6x6 inch plates with at least 4 bolts and backup plates to secure cage to pan or if welding then proper gusseting... Also consider things like head room... Putting bars right over driver's head may be nice protection, but be sure its high enough driver does not bang head into it under normal driving... Lot's of really good designs out there, also plenty of poor ones... Done wrong, you may have caused yourself a lot of grief because it can hurt you just and easy as protect you (done right) in a incident....

Soon Dusty Mojave will come long and detail what material and how to design, listen to him, he has done many tech inspections on off road and on road race cars he knows his stuff...

On both my cars, I had someone experienced with building cages because it was cheaper to have it done by experienced person with all the tooling and welding capabilities than for me to buy all the tools (benders/notchers/bigger welder) and ruin untold how many feet of tubing with bends in wrong places and wrong angles and possibly poor welds...

Dale

Sat Jul 14, 2018 8:19 am

1 5/8" tube is a weird size and often more expensive than 1 3/4.

Sat Jul 14, 2018 9:11 am

Dale and Trip, Thanks.

Dale,

I have a use for a light duty tubing bender and nocther for my business, so I can write those off.

And, I can use it for the tree bars, bumper racks, etc.

Anyway, mild steel or chrome molly?

Donnie

Sat Jul 14, 2018 10:17 am

On that light weight buggy I would just use 1.5 x .120 mild on the main cage. I see no need for Cro-Mo. I am still building race Legal cages for 2000lb and under cars using 1.5 x .120 on the main cage and .095 mild steel on every thing else. I have a car just now in the shop that I am replacing the body on that survived a flip and roll over with no cage collapse that was mild steel 1.5 x .095 . If you are experianced with Cro-Mo and can use a Tig then go with that as it is preferred but not neccesary. Just a better Mig then what you have will work fine on a mild steel cage. I am assuming your not building for drag racing which would be a whole different use over just recreational.

From the SCORE rules as example for that Org.

Sat Jul 14, 2018 10:28 am

Old,

Just for street use, and the occasional off road rump. Not much for then that for my new of the woods (Baltimore/DC Metro).

Donnie

P.S.

Thanks!

Sat Jul 14, 2018 11:57 am

Street use.
Frame-.095 x 1.5
Engine cage-.120 x 1.5
Frame deformed more than the engine cage. Wrapped solid motor mount around framehorns. Way more f@#ktards on the street. Don't under estimate your loved ones safety. This one also took out my engine.

Typical bolt on cage. This was a very lite hit. This one took out 1 side exhaust, #1 exhaust studs. and #1@ #2 push rods/tubes.

Sat Jul 14, 2018 1:47 pm

in re chrome molly:

you weld up a roll car cage for a serious race car
have the welds inspected by a guy with calibrated eyeballs
have them x-rayed, magnafluxed, zyglo'ed
car is certified for the serious race car class for 5 years
after which it is downgraded: supercharged OR exotic fuel, not both.

just use DOM

https://www.thesamba.com/vw/forum/viewtopic.php?t=576592
https://www.thesamba.com/vw/forum/viewtopic.php?t=403791
https://www.thesamba.com/vw/forum/viewtopic.php?t=379110

Sun Jul 15, 2018 2:34 am

Chrome moly is for race cars that will be raced for a couple of seasons and sold or cut up for parts for the new race car.

DOM is nice but not cheap

ERW is cheap and will stand up to most things a play buggy will see, just put the seam on the inside of the bend where possible.

JD Squared model3 bender is a nice bender, go hydraulic if you can the ratchet system works but it will wear you out on some of the bigger tube bends.
For the dies try not to go tighter then "3 time the diameter-center line radius" of the tube. So for 1 1/2" tube no smaller then 4 1/2" CLR, I like 5 1/2" CLR because you get a better quality bend with less wrinkles, you can do 1 1/2" X.065" but it will have some wrinkles on the inside of the bend, 1 1/2" X .095" or thicker bends great though. Make sure to use lots of lube on the "Follower die" to get a cleaner bend! Don't buy 90° dies, get the 180°, you kick your self if you don't.

https://www.jd2.com/model-3-bender

Casey

Sun Jul 15, 2018 9:31 pm

As Dale predicted above...Here I am. And yep. I started Tech Inspecting race cars in 1963.

IMHO, DOM is THE BEST MATERIAL for roll cages. Having said that, the roll cage in my own Baja is 1010 mild steel CREW (aka "ERW). NASCAR bans use of 4130 in roll cages for many reasons that I entirely agree with. I have a fiberglass buggy project sitting waiting its turn in the priority list. It will get 1.5" x .095 ERW tube. I have a 5-1600 Baja Bug race car project. I expect it to weigh over 2000lbs when ready to race. It will get 1.5" x .120 DOM for the primary cage bars: A-pillars, B-pillars, Roof bars ("halo"), Diagonal behind driver, Rear braces. All other bars will be 1.5" x .095 or 1" x .065 ERW. They will be plenty for non-critical members.

I recognize your buggy is NOT a race car. But as I said in your other thread (and this 2nd thread REALLY should have been part of that thread - no need to spread things around, it's all about the same car):
Quote: So for street or dirt, I strongly recommend a roll cage. FAR more important for the street due to all of the other battering ram vehicle driven like the streets are in Death Race 2000. Ask cbeck about driving a buggy on the street. I'm not saying the cage HAS to be a full SCORE legal race car roll cage. But some protection from Stupid out there. And not so much for protection in case of inverted operation either. more to keep the cockpit a reasonably safe place to be. Side impact protection is made more difficult in your buggy due to the cutout "door" in the left side as compared to most Manx-style buggies. But some tree bars would help that. The cage could even be a hoop under the dash in the front tied to a 4-point rear roll bar to keep that "Open Air" feel to the car. But since it will almost certainly have a windshield, you may as well have a front hoop close to the windshield frame.

I suggest diagonal door bars from the bottom of the A-pillar up to elbow level (top edge of body side) on the B-pillar post. Horizontal door bars between the bottoms of the posts would make for a complete triangle (strongest structure shape. Both for side impact. Makes a strong roll cage and chassis, but that's just a side consideration for this car. Bracing to the beam from the A-pillar would be nice, but not absolutely necessary. A dash bar of 1.5 x .095 would help in side impact and the steering column could be supported off it. A bar across behind the shoulders, would be good for mounting shoulder harnesses and also provide side impact strength. The rear braces should go to a bar across under the back of the body shell and brace down to the steel motor mount at the bell housing or the trans support yokes near the ends. There should also be structure from the torsion housing or stock upper rear shock mounts. Supporting a roll bar by attaching it to the fiberglass is pointless unless the fiberglass is supported from underneath by structure.

Where the cage mounts to the floor should have not only 3/16" thick base plates, it should have similar plates underneath with 3/8" bolts through both. While 6" square plates are called for by some race organizations, I consider that to have been based on old rules considering a roll bar, as compared to a roll cage. I feel 2" wide x 4" long provides a good base plate for a cage.

Sun Jul 15, 2018 10:42 pm

On the base plates you use to attach to the pan, make sure to round of the sharp square corners and edges, they make nice sharp chisel points to cut holes in the pan on a roll over. I like replace the floor pans with 16g steel sheet, its a little tougher the stock pan and way thicker then the replacement pans on the market these days. When I get around to making a cage for the dune buggy I have I am going to add a 1" x 1 1/2" x .120" wall rail around the out side of the pan like a body lift to have some thing more substantial to weld to for the cage, I will bend a 1" flange on the base plates and weld it to the tube and floor.

Casey

Tue Jul 17, 2018 7:46 am

YOU GUYS ROCK!

Thanks you!

Tue Jul 17, 2018 6:29 pm

You can check my build thread below there’s quite a few pics.
Mines 1.5 .120 wall erw. Built with a JD2, I do notching in a drill press with a 1.5 hole saw and a little jig I made or just a torch. I use a 170 amp mig welder and sometimes it’s not enough to do what I want. I had one that was built with a stick welder that my dad wrecked pretty bad and the welds all held, I’m not sure if I’ve ever seen failed welds on a buggy in an accident, it’s usually tube that crushes. Older sandrails rust out from the inside out now and then too, those are the most dangerous failures I’ve seen. My brother was so convinced he poured ospho down all his tubes and rolled them around before welding.

Wed Jul 18, 2018 10:36 am

OP, Please do not take this the wrong way, You say you have a 110v MIG welding machine but are you a WELDER?
NEVER LEARN TO WELD, BUILDING YOU FIRST RACE CAR!
Or in your case building your play car, I had a good friend killed because a tube broke loose in his car and stabbed and killed him in a bad roll over.

Casey

Wed Jul 25, 2018 5:46 pm

earthquake wrote: OP, Please do not take this the wrong way, You say you have a 110v MIG welding machine but are you a WELDER?
NEVER LEARN TO WELD, BUILDING YOU FIRST RACE CAR!
Or in your case building your play car, I had a good friend killed because a tube broke loose in his car and stabbed and killed him in a bad roll over.

Casey

Casey,

I am not a welder. And alcoholic yes. But not a welder.

Thank you for your concern, and for looking out for my best interests.

I very sorry to hear your fiend lost his life. Life is very short, and our end is heartbeat away. Live it while you can!

I can tack it together, and have a pro finished it up if I need help.

Found some plans to get going, too.

http://www.vdubn.com/dunebuggys/Manx/rollcage/rollcageindex.htm

Wed Jul 25, 2018 10:31 pm

This is that cage (the 2" lower roof version included in the plans and special for his own buggy with a cut down windshield):

It's a fair design for the basic cage.

The rear braces end at the fiberglass back panel. Unless some structure is built on the other side of the fiberglass, it provides very little strength where it really is needed. My friend's California Clipper has such a structure under the fiberglass which has shock mounts on the sides, and the rear mounts to the top edge of the body, where the upper cage mounts to the top side and connects with bolts to the under structure. It connects to the bumper and down to the engine yokes.

I'm suggesting this, not demanding it. But take note of cbeck's buggy and Baja Bug above. Your under-glass structure design doesn't have to be the same as I showed in my picture above, but the connection points should probably be similar.

I also suggest attaching the rear braces to the b-pillar hoop just inboard of the bend to vertical and the over the head roof bars opposite them. More like in the cage I built. Having the roof bars inboard as shown in the vdubn.com pictures makes for more head clearance getting in and out. But is weak and not good for safety.

Thu Jul 26, 2018 5:58 am

dustymojave wrote: This is that cage (the 2" lower roof version included in the plans and special for his own buggy with a cut down windshield):

It's a fair basic design.

The rear braces end at the fiberglass back panel. Unless some structure is built on the other side of the fiberglass, it provides very little strength where it really is needed. My friend's California Clipper has such a structure under the fiberglass which has shock mounts on the sides, and the rear mounts to the top edge of the body, where the upper cage mounts to the top side and connects with bolts to the under structure. It connects to the bumper and down to the engine yokes.

I'm suggesting this, not demanding it. But take note of cbeck's buggy and Baja Bug above. Your under-glass structure design doesn't have to be the same as I showed in my picture above, but the connection points should probably be similar.

I also suggest attaching the rear braces to the b-pillar hoop just inboard of the bend to vertical and the over the head roof bars opposite them. More like in the cage I built. Having the roof bars inboard as shown in the vdubn.com pictures makes for more head clearance getting in and out. But is weak and not good for safety.

You be the man, Dusty!

Thu Sep 13, 2018 4:14 pm

I have gained tons of info from threads on Sambas past postings. So I'm posting this here for the OP and others reference in the future.

I needed a bender for my street legal FRP 4 Seat mid travel wide body Dual sport build, as a mild street/hard pack desert car. I did not and could not, due to space and slope, floor mount a bender,. A Pro-tools HD105 from Tricktools.com. So I converted the manual horizontal bender to a vertical Electric Bender. I have been very happy with it for the low cost.

I added a 3,500lbs electric trailer tongue jack (approx. $135) and a surplus ebay 12v 75amp server power supply (approx. $40) A couple leads and some angle iron for the stand and done. Portable and easy to store/use in a tight space. It is S....L....O.....W but makes very nice bends in the 1.5"x.095 DOM I used thru out.

I used a Eastwood notching tool mounted to a sturdy bench and a cordless drill set to low speed. I got good result and life out of the Milwaukee brand Dozer hole saws. I think I only used 3 on the hole cage. If you are going to have it MIG welded, make sure to grind in a good bevel for all connections. Some of my gaps are tight and not beveled well. Self welding the core cage including cage mounted seats and belts when family & myself are involved is out of the question. And not just anyone, literally someone I would trust my families life with. I have asked other fabricator who they would have TIG weld their personal cage and interviewed that person. Bumpers and brackets I will MIG in.

Another tool that was very useful was a digital angle finder. I got the GemRed small magnetic version from Amazon. It is accurate and really helped me hold my angles during bending and tacking-up.

"Tacking up" I choose 1.5"x.095 DOM by my estimated weight. If ERW I would have used .120. Tacking up with a 110v machine might be OK if you do not need to transport it for "professional" welding. 220v will give you a proper penetrating hot tack, esp if using .120ERW. My picture as a roller on the trailer was just tacked up during a house move. I choose the new orange Vulcan welders from HF. It came with a 2yr satisfaction refund or exchange guarantee and is dual voltage and replacement parts/consumables are reasonably priced.

Cage design is a complete other discussion especially if going with coilovers. In hind sight I wish I had left the rear torsions w/bypass shocks and the front coilover. Getting the stock torsion housing/pan structurally tied back into the upper coilover mount has been a challenge. (remember the cage will be removed for welding) I would not run a 6 point pan mounted cage with a fiberglass body. Street or Off-road.

That's my story and I'm stickin to it...............

Thu Sep 13, 2018 5:21 pm

Awesome build!