Bent Tube Thickness measurement |
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shrivara
Bolt Sorter Joined: Nov/14/2013 Location: Bangalore Status: Offline Points: 39 |
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Posted: Apr/24/2015 at 12:08pm |
Guys! I saw a photo of a car undergoing technical inspection where one of the judges was inspecting the tube thickness especially at the bends using some kind of instrument...
All I wanted to know is 1. Did u guys undergo through such process in any of the events so far?? 2. If at all I wanted to know what is the thickness at the bent portions of my rollcage, what can be done? 3. Is it really necessary to check thickness of tubes at bends??
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rasmuet
Welding Master Joined: Apr/29/2013 Location: Ann Arbor, MI Status: Offline Points: 310 |
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That is part of technical inspection checking for the minimum thickness of primary material in your roll cage and throughout the vehicle. It is necessary to check the thicknesses of the tubes at the bends because if you had primary material at (.062" thickness) and you had a significant bend you may no longer meet that rule.
It is essentially an ultrasound for metal tubes.
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Erik
Iowa State Baja 2011-Dec 2014 Drivetrain Design 2013, 2014, 2015 2014 Kansas - Car #45 - 1st Place Endurance |
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Ruturaj
Bolt Sorter Joined: Apr/04/2015 Location: India Status: Offline Points: 6 |
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Which event are you talking about BSI Jamshedpur or Baja Sae India 2015? We were at Indore and i was at Tech inspection with our car ,none of the inspectors checked our rollcage thickness by any instrument. They just asked dimensions that's all!! I don't remember such in other bays too
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vin2000
Welding Master Joined: Sep/23/2013 Location: Bangalore,INDIA Status: Offline Points: 147 |
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He is talking regarding US events where frame check is carried out in every detail. Both the events in India don't do that as far as I know.
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RVCE-BAJA
2011-2015 www.thrbaja.com |
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Richie_Dagger
Baja Godfather Joined: Sep/25/2011 Location: Las Vegas, NV Status: Offline Points: 615 |
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Never seen 'em check our bends. They always picked straight members. Checking bends is lame, unless you just want everyone to run 1x0.120 frames or square roll hoops...
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RLM
Baja Godfather Joined: Nov/15/2012 Location: Hamilton, ON Status: Offline Points: 1258 |
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They have checked our thickness in bends almost every year. We just upsize to the next thickest material above the rule to account for thinning in the bends. this is a good idea regardless of whether they check or not as by bending the tubes you are stressing the material and causing it to be more succeptable to failure. last thing I want to see is someone get seriously injured from a frame failure just so a team could save a pound of weight. if your that desperate for weight savings to compromise safety, just lay off the cheeseburgers and pizza in the weeks leading up to comp and take a monster dump before you go out on the track.
Safety first.
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McMaster Baja Racing (09-Dec 2015)
Team Captain 2012-2015 Suspension Lead 2015-2016 All spoonfeed PM requests will be billed at $10 USD per reply, payable via paypal. |
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Elpwnage20
Welding Master Joined: Apr/12/2014 Status: Offline Points: 225 |
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How are you supposed to respond to that though? There isn't anything in the rules about this and there is no way that a team would know that they require this unless looking at the forum. Would you basically be disqualified and not allowed to race cause of this?
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shrivara
Bolt Sorter Joined: Nov/14/2013 Location: Bangalore Status: Offline Points: 39 |
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Yeah.. I completely agree with RLM that it is the " Safety First"...
But if you are going to use the next thicker material above the rule how can you be sure that because of thinning the thickness wouldnt come below the rule( for different bend radii)??
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Elpwnage20
Welding Master Joined: Apr/12/2014 Status: Offline Points: 225 |
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Also, how are they supposed to check the thickness of a bent tube?
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zglazer
Baja Godfather Joined: May/27/2012 Location: Metro Detroit Status: Offline Points: 593 |
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The little ultrasound machine Erik described is used to check tube thicknesses of both straight and bent sections.
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Zack Glazer
McGill Baja Racing Alumnus 2009-2013 http://baja.mcgilleus.ca/ 2012-2013 Drivetrain Designer |
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sweeneyp
Milling Master Joined: Sep/26/2014 Location: Nashville, TN Status: Offline Points: 76 |
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interesting, they've never once checked a bend on ours.
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The odd EE that does baja
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Aztec Warrior
Welding Master Joined: Jan/18/2014 Location: San Diego Status: Offline Points: 329 |
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I've been thru tech 5 times. I have never seen a thickness checked at a bend. All they are trying to do is make sure you are useing the tube dimensions you are claiming on your roll cage spec sheet. Everyone uses 1.25 x.065tubing. If they checked at bends, they wouldn't have enough cars to run the race. Believe it or not tech officials are not out to get you.
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"To finish first, you must first finish"
SDSU Baja 2010 and 2014 McMillin Racing 2005-present |
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shrivara
Bolt Sorter Joined: Nov/14/2013 Location: Bangalore Status: Offline Points: 39 |
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Well, its interesting to see diversified opinions on this topic...
@Aztec as u said most teams use 1.25x0.065 tubing what bothers me is due to thinning is there any chance of thickness getting reduced less than 1.57mm as mentioned in the rules?? |
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Aztec Warrior
Welding Master Joined: Jan/18/2014 Location: San Diego Status: Offline Points: 329 |
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There is a chance. I am sure you could estimate the thinning with a simple equation (conservation of volume). But personally I have never worried about it, and have not had problems with it. I actually talked to the guy checking in auburn, and he said that he normally sees thickness vary down to 0.063 (in straight sections), and he passes those cars as there is a tolerance in thickness of tubes. He also mentioned that thick paint can add a couple thousandths. So if you are worried about it, put a couple extra coats of paint on the bends. I really don't think it is a safety thing. That is plenty strong tubing for the speeds we are going (as long as it is notched and welded properly.
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"To finish first, you must first finish"
SDSU Baja 2010 and 2014 McMillin Racing 2005-present |
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Pedro UFPBaja
Baja Godfather Joined: Mar/03/2010 Location: Brazil Status: Offline Points: 886 |
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If they check the thicknes sideways will be the same as original.
Unless the car has a very small bend radius, with severe profile lost, i really don't see any safety issues |
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i6overboard
Welding Master Joined: Sep/22/2013 Location: New Orleans Status: Offline Points: 108 |
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This is more of problem than any thinning of the bend area.. Techs are for the most part nice guys, if I was doing tech I give more people crap about the welds they are putting out, but i guess what should they expect when most of welders only have a year or so of experience max. Like a few others have said, they just make sure you used the tubing that you say you've used and you'll be in the clear... |
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