T3 tube-through-tube joints - history 1

[Gordo35]

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

 

[ivymike]

are you talking about fishmouth joints?

 

[Gordo35]

"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

 

[GregLocock]

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 for tips on how to make the best use of Eng-Tips.

 

[Gordo35]

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

 

[GregLocock]

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 for tips on how to make the best use of Eng-Tips.

 

[Suzi08]

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