• Registered: 2009-05-01
  • Posts: 96

Re: Cage tubing question

Plate thickness...This is from NASA rule book:  15.6.14 Each mounting plate shall be no greater than one hundred spuare inches and no greater than twelve inches or less than two inches on a side.Welded mounting plates shall be at least 0.080 inch thick. Each mounting plate should have an area of not less than nine square inches.
Also...15.6.14.A Mounting plates-Bolt-in cage..The attaching points of a bolt-in cage to the body must use reinforcing plates to sandwich the body. At least three bolts are required for each bolt-in plate and the plate must be at least 3/16 inch thick.  All hardware must be SAE grade 5 or better with 5/16 diameter minimum.  All nuts must be held securely by a locking system such as safety wire, lock washer, ny-lox, or jam-nuts.
I think these guidelines will pass Lemons tech.

sawinatthewheel...sometimes too much, sometimes not enough...just like life

52 Reply by troubleonwheels (edited by troubleonwheels 2009-06-03 05:22 PM)

  • From: Portland, OR
  • Registered: 2009-04-30
  • Posts: 201

Re: Cage tubing question

http://farm4.static.flickr.com/3201/3060288140_9ee142861a.jpg?v=0
damn that welding looks WAY better than I remember it being.

Erik
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Re: Cage tubing question

troubleonwheels wrote:

damn that welding looks WAY better than I remember it being.

What do you mean, there is virtually no penetration of the weld from the plate to the underlying sheet metal.  All that undercutting is bad, mmmmmkay?

--Rob Leone Schumacher Taxi Service
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  • From: Portland, OR
  • Registered: 2009-04-30
  • Posts: 201

Re: Cage tubing question

RobL wrote:
troubleonwheels wrote:

damn that welding looks WAY better than I remember it being.

What do you mean, there is virtually no penetration of the weld from the plate to the underlying sheet metal.  All that undercutting is bad, mmmmmkay?

ooooooo if only you knew what I know .....

Erik
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Re: Cage tubing question

I only weld with 10mph draft thru the car  !

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  • VKZ24
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  • From: Wilson, NC
  • Registered: 2009-05-20
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Re: Cage tubing question

RobL wrote:
troubleonwheels wrote:

damn that welding looks WAY better than I remember it being.

What do you mean, there is virtually no penetration of the weld from the plate to the underlying sheet metal.  All that undercutting is bad, mmmmmkay?

From the looks of the bead, the weld was too cold hence the convex appearance.  A full penetration bead will appear flat or a little concave.

I will say that I saw welds that looked about 10X worse at previous events.

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  • Registered: 2009-04-30
  • Posts: 14

Re: Cage tubing question

TestDriver wrote:

Who do we ask for waivers or grandfathering requests of? I've asked this before of the Grande Poobah. Should I just send him a request again?

Thanks.

Never mind.

Ramon Mendoza
El Blackie Chaparral Racing
  • Registered: 2009-12-26
  • Posts: 443

Re: Cage tubing question

Tube Bends.

Is it sufficient to bend tubes against a die (such as with a jd2 bender does) or must they be bent with a mandrel inserted in the tube?  Mandrel shops are pretty pricey.

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  • Mulry
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Re: Cage tubing question

We used a JD2 bender (or a pro-tools bender, they're essentially the same thing) and our tubes were fine.

Pat Mulry, TARP Racing #67

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  • Registered: 2009-12-26
  • Posts: 443

Re: Cage tubing question

I'd like to add a leg to the cage that goes between the front suspension pickups and the front post of the cage at or near the knee crossbar.  It's a unibody car and I'd like to stiffen the chassis for handling purposes.  It seems like this could have the negative effect (in a crash) of eliminating some front energy absorbing crushability.  It would transfer a front crash shock directly to the cage near the knees.

Good or bad?  Any opinions?

“Never attribute to malice that which is adequately explained by stupidity.”

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  • mikesr
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  • Registered: 2009-10-23
  • Posts: 102

Re: Cage tubing question

Could go either way depending on the impact. If it's a crusty old crapcan it's going to fold more than the crumple zones were designed for. In that case, the extra bars would keep the engine out of the drivers compartment. However, YOU  would take more G's. A good seat and correct belts will be there to help with that. Remember, crumple zones were engineered for stock seats and belts.
A few years ago the Nascar modifieds were killing a lot of good drivers due to over the top re-inforcement on the front end. New rules for crumple zones (as well as better safety equipment) have helped.
Just don't over do it. I would suggest a 45 degree downward angle from the dash bar. A hard hit should deflect the forward part of the enginge compartment upward in a fold.
If you want to stiffen the front, a cross piece of tubing between the frame rails or cradle will help with little effect on the zones.
We made some circle track tanks in the past: So stout we were breaking the engine mounts and smashing the radiators with no crumple at all. Now we know better.

Be safe,
Mike Sr.

  • Registered: 2009-12-26
  • Posts: 443

Re: Cage tubing question

Thanks.

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