×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

T3 tube-through-tube joints - history

T3 tube-through-tube joints - history

T3 tube-through-tube joints - history

(OP)
Can anyone direct me to historical design references to what Ford (F-150 frame) and John Deere now refer to as "T3" or "tube through-tube" joints? The joints are generally at 90 degrees (or possibly from 75 to 105 degrees) and are not telescoping joints.

Based on a photo, Alex Moulton (suspension designer of the early Austin-Mini) appears to have used a round horizontal tube (quill) which fully pierced the seat tube of the 1960's Moulton bicycle.

It appears that "round tube through tube" joints have been around for sometime, but none of my associates are familiar with the history of the practice.  Does anyone know the historically correct terminology for this type of joint connection?

Thanks-
Gordo35

RE: T3 tube-through-tube joints - history

are you talking about fishmouth joints?

RE: T3 tube-through-tube joints - history

(OP)
"T3" or "tube-through-tube" joints replace fishmouth and butt joints.

Ford describes T3 joints as: "... tube-through-tube frame design, where the cross members pass through the section of the frame-rails, creating an inherently stronger joint. These joints are then completely welded around the perimeter for a fully boxed seam.".

Ford F-150 (and Explorer) frame-rails are now a full rectangular box section, rather than the former "C" channels.  Holes are cut in both the inner and outer sides of the rectangular box sections, in order that the cross members can be welded to both the inner and outer sides of the box section.  Alex Moulton used essentially the same technique with round tubes.

Thanks-
Gordo35

RE: T3 tube-through-tube joints - history

Ford Thunderbird 1955 used at least one tube through chassis joint.

If the efficency of a nasty old box to box butt joint is 50-60%, a tube through box joint can have an efficiency of around 90-95%

Exactly how that efficiency is defined depends on your goals and geometry.




Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: T3 tube-through-tube joints - history

(OP)
Greg-

Thanks regarding the 1955 Thunderbird tube-through-tube information!

I purchased my first auto in 1969, a turquoise 1955 Thunderbird!  I regret having agreed to sell it by phone, while I was stationed in Germany.  Although, my wife (of 34 years) has told me her roommates advised her to date me because of the '55 Thunderbird.

What experience have you had with the '55 Thunderbird?

Thanks-
Gordo35

RE: T3 tube-through-tube joints - history

I've been designing a new chassis, front suspension, and rear suspension for one (don't ask why). It is all roughed out, now I need a CAD guy.

Cheers

Greg Locock

Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.

RE: T3 tube-through-tube joints - history

Hey Greg
Have seen quite a few of your replies lately on various subjects and to various folks - appreciate your style, helpfullness and apparently wide knowledge plus common sense.
May have some questions myself some day.

Paul

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources