Date: Sat, 15 Mar 2008 14:22:21 -0500
Reply-To: John Rodgers <inua@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Rodgers <inua@CHARTER.NET>
Subject: Re: Building carrier (load bar) Square or rectangular tube steel?
In-Reply-To: <c4e7c5f90803151100h4fb0a836t90d6216ee9d331a9@mail.gmail.com>
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My experience with the tube strength issues comes mostly form my work
years ago with welding on small aircraft airframes. Most that I worked
with were constructed of round tubular steel. It has been a long time,
but I seem to remember that most were made of 4130 chromaloy steel., a
very strong, tough metal. Welded up properly a section made of this was
practically indestructible in compression loads. But bending loads were
another matter, and that applies to most any round tube. Square or
rectangular had limited application. They were used, but not for full
frame construction. Those kinds of tubes has special applications.
John Rodgers
88 GL Driver
neil N wrote:
> Thanks John.
>
> This is also what the metal guy expressed, so I was curious to "hear"
> what more educated minds had to say. FWIW, the stock air cooled (and
> WBX I think) is very much a rectangular shape. From memory, looks like
> 1" by .5" Obviously designed to handle L to R movement.
>
> I have some scraps of hot rolled 2"x2" and plate steel (that the metal
> guy kindly gave me) that I can try my hand at for practice fitting and
> welding. I will play with wood scraps to find my angles first. It
> looks like it's all 45's with the exception of the 90 needed to hang
> from the subframe.
>
> Once I get the engine at the right "height", and make some test pieces
> out of wood, I should be able to determine how long the long side of
> the rectangle can be before the bottom of the carrier hangs too low
> below oil pan.
>
> (he says thinking outloud to no one in particular --- ;^)
>
> Neil.
>
>
>
> On Sat, Mar 15, 2008 at 10:35 AM, John Rodgers <inua@charter.net> wrote:
>
>> Neil,
>>
>> I'm not an engineer, but I would think that a tube with rectangular
>> crossection would have the greater strength, depending on the directions
>> loads are applied. Just my opinion.
>>
>> John Rodgers
>> 88 GL Driver
>> Chelsea, AL - where it's thundering, lightening, and pouring down rain.
>> Ahhh! Spring showers!
>>
>>
>>
>> neil N wrote:
>> > Hi all.
>> >
>> > I am ready to fabricate the engine carrier for my 15 degree Jetta conversion.
>> >
>> > Is 1/8" - 2"x2" hot rolled tube rigid enough?
>> >
>> > Or should I use rectangular tube? ( 2"x 2.2.5" ? 2" x 2.5" ?)
>> >
>> > Will the rectangular shape add strength/stability ?
>> >
>> > For sure 2" is needed for base of Fox mounts I'm using.
>> >
>> >
>> > TIA,
>> >
>> > Neil.
>> >
>> >
>> >
>> > --
>> > Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
>> >
>> > http://web.mac.com/tubaneil
>> > http://tubaneil.googlepages.com/
>> >
>> >
>> >
>>
>>
>>
>>
>
>
>
> --
> Neil Nicholson. 1981 Air Cooled Westfalia - "Jaco"
>
> http://web.mac.com/tubaneil
> http://tubaneil.googlepages.com/
>
>
>
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