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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12861
Location: North Carolina
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 Posted: Tue Jun 23, 2015 5:51 pm Post subject: Hey Richard! |
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| I have a question for you, these class 11 "style" cages that are available through the off road vendors, are these really something that would pass one of your tech inspections? Would it be a good starting point to tie into the rest of the car or would I be better off just getting 40' (or more?) of .095 1.5 DOM? Thanks for any input, Chris. |
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no1clyde
Samba Member
Joined: August 27, 2013
Posts: 365
Location: Elko Nv.
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| Posted: Tue Jun 23, 2015 6:17 pm Post subject: |
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TDCTDI I have right at 120' of 1.5 mild steel tube, half is .120 and half is .095 so I would plan on more tube. I will be using at least 1 more 20' stick for diagonal, door bars and a bit more in the roof. This is the basic cage.
and with body and rear cage.
And the front bumper.
As far as the class 11 stuff I am no help as this is the only Baja I have done and I'm just winging it.
Ed |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12861
Location: North Carolina
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| Posted: Tue Jun 23, 2015 6:57 pm Post subject: |
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| I've been watching your build, love it. I meant 4 20' sticks of 1.5 which would be 80' but the class 11 kits are cheaper than the tubing itself. I was just wondering if people actually get these kits & if they would be able to get through a sanctioned tech inspection with one. I don't plan on racing mine but I do intend on pounding the dogsnot out of it & would like a cage just in case. |
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no1clyde
Samba Member
Joined: August 27, 2013
Posts: 365
Location: Elko Nv.
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| Posted: Tue Jun 23, 2015 7:18 pm Post subject: |
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Thanks for watching. I don't think the class 11 kits are DOM but I may be wrong. Any way a 20' stick of .095 mild steel here is running around $33-$35, seems to change by the week LOL.
Ed |
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dustymojave
Samba Member
Joined: January 07, 2007
Posts: 5802
Location: Lake LA, Mojave Desert, SoCal
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| Posted: Thu Jun 25, 2015 3:22 pm Post subject: |
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| TDCTDI wrote: |
| I have a question for you, these class 11 "style" cages that are available through the off road vendors, are these really something that would pass one of your tech inspections? Would it be a good starting point to tie into the rest of the car or would I be better off just getting 40' (or more?) of .095 1.5 DOM? Thanks for any input, Chris. |
I will not guarantee that other Tech Inspectors will pass a cage which is made of 1010 CREW or as some vendors inaccurately call some tubing "HREW", But if it's painted, how would they ever know?
Now that I seem to be encouraging cheating...If I had been wearing Bill Savage's shoes when he banned mild steel for the 2006 SCORE Rulebook, I would instead have banned 4130. In all of my years of Tech Inspecting, including post-crash investigations having been a specific duty of mine, I have never observed CREW tube fail at the tube seam. I HAVE encountered a great many 4130 and English equivalent tube roll bars and cages crack and/or snap clean off the car. As a professional race car fabricator, I could not count the times I've repaired cracks and/or replaced cages or roll bars of 4130. NASCAR, for instance, prohibits use of 4130 in cages. HDRA did for offroad race cars back in the '70s. In some race organizations, including some I have spent years working Tech for, mild steel tube is fine.
My personal favorite tube to use for building roll cages and chassis structure for an offroad car, whether race or not, is 1020 DOM. I've encountered DOM offered in different alloys over the years: 1010, 1018, 1020, and 1026. The last 2 digits of a steel alloy indicate the percentage of carbon in the alloy. The greater the carbon content, the stiffer the steel is. Also, the more brittle the steel is. 1026 gets rather brittle and is inclined to cracking. 1020 DOM is tough stuff. Stiffer than 1010 CREW, but still not inclined to work-harden and fatigue.
The off-the-shelf cage kits are made of 1010 CREW. If anyone tells you it is HREW, you have my encouragement to call BS. Hot roll steel is rough surfaced and blue-gray color like angle iron or the slag from stick-arc welding. If the metal is shiny, it's NOT Hot Roll.
I have said many times on this and other forums that I would accept 1010 CREW material for a race car roll cage. That's what the cage in my own Baja Bug is made of. It's what the whole chassis including the cage of my Hi Jumper race buggy is made of and tested in a flat-out speed quadruple endo with NO damage to the cage at all. When I changed seats in my Buggy and needed more head room, I redid the cage in 1010 CREW. So, yeah Chris, I trust my life to the stuff.
The ONE aspect of those Class 11 cage kits I DO NOT approve of, is the B pillar hoop top corners. For shipping purposes, the B pillar hoop is made in 3 pieces, top and left and right sides uprights. The uprights have a bend at the top and there is a small piece of 1-1/4" tube slipped inside the end where the joint is to be made. That is intended to be fit into the end of the top piece to reinforce the joint. That piece should be 2x the OD of the main tube long on both sides of the joint. It should also be rosette welded on both sides of the tube and both sides of the joint about 1 tube OD away from the joint With the side tubes being cut right at the tangent (end) of the bend, the inner sleeve cannot possibly be inserted as far as it needs to be. and because of this lack of insertion depth, it cannot be rosette welded either. So I always recommend replacing that B pillar hoop with a 1-piece hoop. A shoulder bar should be added to attach harnesses to and I suggest adding a front structure to the beam to support it also.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12861
Location: North Carolina
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| Posted: Thu Jun 25, 2015 3:34 pm Post subject: |
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| Thank you sir, now I just need to find out if my local steel supplier wl deliver to me & how much. |
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dustymojave
Samba Member
Joined: January 07, 2007
Posts: 5802
Location: Lake LA, Mojave Desert, SoCal
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| Posted: Thu Jun 25, 2015 3:36 pm Post subject: |
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Wow! Ya'll musta been watchin' when I posted.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12861
Location: North Carolina
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| Posted: Thu Jun 25, 2015 3:37 pm Post subject: |
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| Is .095 sufficient for main structure or should I go .120 as no1clyde has done? |
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dustymojave
Samba Member
Joined: January 07, 2007
Posts: 5802
Location: Lake LA, Mojave Desert, SoCal
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| Posted: Thu Jun 25, 2015 3:57 pm Post subject: |
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Yes .095 is fine.
I've seen a Class 11 race bug with one of the off-the-shelf Class 11 cages going 35mph (by their gps) get rear-ended by a 5,000lb Class 1 buggy going 135mph (by their gps) near Slash X at Barstow. The back of the Bug looked like a nuclear weapon went off. The body was shredded off nearly to the windshield. But if the alternator, fan shroud and intake manifold weren't torn off, they could have finished the race. And the 2 guys who were in the Bug when it was hit told me that. The cage was scraped, but entirely undamaged. They were planning on replacing the body and keeping the cage. The guys in the Class 1 car went to the hospital to get checked out.
The Class 11 cage kit is made in .095 wall 1.5" OD mild steel because that was what the SCORE rule called for. It does not include front structure because it was not allowed when Lynn Chenowth designed the cage kit. The original kit included a 1-piece hoop as I recommended earlier.
_________________
Richard
Offroading VW based cars since 1965
Tech Inspection 1963 - 2012 SCCA/SCORE/HDRA/MORE/MDR +
Retired from building Bajas, Fiberglass Buggies and Rails in the Mojave Desert. Also Sprints & Midgets, Dry Lakes, Road Race cars. All types New and Vintage
SoCalBajas Member
Kicked Cancer's A$$...1st and 2nd round...Fight ain't over yet. |
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TDCTDI
Samba Advocatus Diaboli
Joined: August 31, 2013
Posts: 12861
Location: North Carolina
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| Posted: Thu Jun 25, 2015 4:11 pm Post subject: |
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| Thanks again! |
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