pimpm3
pimpm3 Dork
3/18/16 7:39 p.m.

Let's say hypothetically one was to build a roll cage in a parking lot. Let's say it's for a miata.

The person building the cage needs some tools. Unfortunately he only has a 120 volt welder with gas. He is willing to buy a decent set of tools to do the job.

Which bender should he get? Which tubing notcher?

What size tubing, OD, thickness? DOM, ERW? What thickness footer plates?

Anything I am missing?

Adrian_Thompson
Adrian_Thompson UltimaDork
3/18/16 7:42 p.m.

Buy a used roll bar and do the rest with straight bars. Pre notch some bars so you just need to fit the other end when there.

pimpm3
pimpm3 Dork
3/18/16 7:45 p.m.

I have a metal chop saw and an angle grinder already.

pimpm3
pimpm3 Dork
3/18/16 7:47 p.m.
Adrian_Thompson wrote: Buy a used roll bar and do the rest with straight bars. Pre notch some bars so you just need to fit the other end when there.

I would like to build every thing in the parking lot, that's the point of this project.

chiodos
chiodos Dork
3/18/16 7:58 p.m.

Hand drill powered tube notcher, welder, and sawzall

oldtin
oldtin PowerDork
3/18/16 7:59 p.m.

Is there a sanctioning body involved? Check the GCR for the real specs if so. For SCCA specs the weight for under 2500lbs IIRC is at 1.5" od, .095 wall thickness and generally foot plates around the same thickness as the walls - 1/8" would be ok. I'm going from my triumph build with a 2000lb car, so double check the specs. Then again, I over-built because I had a supply of tubes and dies for 1 5/8 tubes. I have a pro tools bender, but used would be the way to go with 6 or 7" radius bend dies. I also have a joint jigger tube notcher. A 120 volt mig will do just fine with .035 wire (.025 wire won't get it done).

MrJoshua
MrJoshua UltimaDork
3/18/16 8:00 p.m.

JD2 bender with a stand built to hook into a trailer hitch. DOM tubing. Look up tubing requirements. It will be 1.5" or 1.75" .125" wall depending on final weight IIRC. The dies are expensive so one size throughout might make sense. Ryerson Tull in Jax has good prices for new tube. Not sure of notcher. Biggest advice-get someone experienced to help.

Rodan
Rodan New Reader
3/18/16 8:30 p.m.

I have a JD2 bender, and built a stand for it based on plans I got online. The stand is on casters and bends in the vertical plane(so it doesn't need to be anchored), using an HF air/hydraulic ram for power. It will also carry an HF tubing roller, which isn't really necessary for building a cage.

The setup works great. I've used it for several projects on my Bronco, and will probably start work on a cage for my Miata later this year. Need another set of dies, though, as I've only got 1 3/4" at the moment. Dies are not cheap, so planning the cage out of a single size will save some $$.

Plans available here: Bender stand plans

For a notcher, I have the Eastwood. It works OK, but I'll probably be buying one that can clamp a curved tube before I start my cage project. The cheaper ones are adequate, but IMHO it's worth spending a little more $$ for the better tool.

I'm using a Lincoln 155 Mig (220V) and it's done everything I've asked of it so far....

NOHOME
NOHOME PowerDork
3/18/16 8:47 p.m.

https://www.youtube.com/embed/mHBanmfn_CA

Worth watching. I second the dress rehearsal cage bend. Sure you can find a local Miata to pose for the stills.

Dead Miatae are common enough that you could have the entire cage rehearsed and shipped to FL for the main event.

stan_d
stan_d Dork
3/18/16 9:07 p.m.

I have a model 3. 1 1\2 die

BrokenYugo
BrokenYugo UltimaDork
3/18/16 9:07 p.m.

Don't forget the 3000 running watt generator to run the welder.

pimpm3
pimpm3 Dork
3/18/16 9:33 p.m.

Is this a good notcher? I have cheap harbor freight one on my work bench already but this this one looks pretty good.

http://www.lowbucktools.com/notcher.html

pimpm3
pimpm3 Dork
3/18/16 9:34 p.m.

In reply to BrokenYugo:

The power should be taken care of with out a generator.

pimpm3
pimpm3 Dork
3/18/16 9:36 p.m.
MrJoshua wrote: JD2 bender with a stand built to hook into a trailer hitch. DOM tubing. Look up tubing requirements. It will be 1.5" or 1.75" .125" wall depending on final weight IIRC. The dies are expensive so one size throughout might make sense. Ryerson Tull in Jax has good prices for new tube. Not sure of notcher. Biggest advice-get someone experienced to help.

The trailer hitch idea is great, I am definitely doing that.

BrokenYugo
BrokenYugo UltimaDork
3/18/16 10:55 p.m.

In reply to pimpm3:

In that event, a proper extension cord. Nothing more frustrating than a welder with the settings drifting as the cord gets hot.

pimpm3
pimpm3 Dork
3/19/16 1:56 p.m.

If the cage meets SCCA specifications for tubing OD and thickness will that be sufficient, or does it have to meet NHRA specifications. Car will run a high 14 tops in 1/4 mile.

Does a car need a wind shield for the challenge?

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