Bent tow bar ears question

[m16ty]

The ends ARE cast/machined

I'm pretty sure they are forged, not cast. Forgings are a little more forgiving but the same concerns still apply. If it were cast, the ears would have broken right off instead of bending like it did.

I know enough though that I can confidently say that it would be relatively easy to get new ones of these cast.

As I said above, I don't think they are cast. Castings are good for engine blocks and such but are far too brittle for high compression and tension loads these towbar ends will see.

 

[Howlin Mad Murdock]

As I said above, I don't think they are cast. Castings are good for engine blocks and such but are far too brittle for high compression and tension loads these towbar ends will see.

Could certainly still fabricate a bunch of these pretty easily. If not to make, it would still be a fun side project (at least to me) to get dimensions to be able make CAD drawings so as to be able to make these. I tried digging around in the TMs but couldn't find any dimensions but one could certainly freelance a design given the pin size, gap size, and the tube/bar size.

 

[m16ty]

The towbar I use, I fabricated the whole thing. I actually built two, one I still have and the other I sold to a guy just to move trucks around his yard. I did some pretty extensive testing and was thinking of making them and selling them but at the end of the day, I didn't want the liability.

Since I fabricated the whole thing, I have no idea what the stock dimensions are of the ends.

 

[gimpyrobb]

A long time ago while sitting in an engineering class, I learned that forging is usually at least one third times stronger that casting. No, there are exceptions to the rule, yadda yadda.

Here is an article that somewhat relates to the topic at hand. I found it interesting, you might too.

http://blog.cmworks.com/forging-vs-casting-which-is-better/

 

[zebedee]

Basic Metalurgy

The tow bar ends (and most feet) are cast, the tubes are extruded (forged), collars are welded (fabricated) to the tubes and the pins are machined. BUT the steel recipe may be different for each component.


I think there is a little confusion with terminology going on here :-

All modern steel is cast - that is how you get from lumps of rock (iron ore) or recycled scrap to 'new' steel. What happens after that is dependent on what is being made.

Liquid steel is poured into molds and is continuously formed - read extruded, which gives us bar, rod, strip, sheets etc.

Casting is where complicated shapes - often hollow are poured with liquid steel as that is the most efficient way of achieving the final or intermediate shape.

Forged steel is anything that is subsequently shaped while semi-solid (read red hot) and that changes the dimensions of the initial cast 'ingot'. Look at the processes of making rail road track. [Read Gimpyrobbs forge/cast article - post #24, for more detailed explanation]

Fabrication is where welding (or riveting in the past) is involved to make larger cross sections more efficiently by joining simpler shapes - bridge girders, tanks etc.

Machining is where a larger ingot (casting), a forgeing or a fabrication is subsequently shaped by removing excess through cutting/grinding etc., often to achieve a greater tolerance/surface condition.


"Engine blocks" of old were made of cast iron (not steel), just like old exhaust manifolds and very brittle.




The critical point here is to know what the metal is composed of - basically its carbon content along with all the other ingredients that make the different Grades of steel. This will determine if, when and how much heat is to be applied.

(It is even possible to weld different grades of steel together - using austenitic rods)



And yes - "Those English guys speak English funny". Chris Kyle - American Sniper.

 

[Bill W]

Looks like your towbar is one without reinforcing collars. Inserts WITH reinforcing collars are different length.

So will a newer collared insert still fit/work in my older non collered bar(s) ???

 

[Recovry4x4]

So will a newer collared insert still fit/work in my older non collered bar(s) ???

Yup!

 

[NDT]

So will a newer collared insert still fit/work in my older non collered bar(s) ???

Fit, yes. Work? If you don't mind towing dog legged.

 

[Recovry4x4]

Fit, yes. Work? If you don't mind towing dog legged.

Care to elaborate? The collars were an MWO. The kit consisted of the 4 collars and some stuff to monitor the temps of the material as it was welded. I don't see how sliding a collar over a tube and welding it would cause the described condition.

 

[doghead]

Eastern Surplus has a pallet of the inner legs, NOS.

Listed on their site.

 

[NDT]

Care to elaborate? The collars were an MWO. The kit consisted of the 4 collars and some stuff to monitor the temps of the material as it was welded. I don't see how sliding a collar over a tube and welding it would cause the described condition.

Hmm, sounds like I am wrong. I am going on an experience Wehring and I had where a collared insert was incompatible with an older med towbar. The legs had inequal lengths.

 

[jasonjc]

With the flood of med tow bar lately just get a new one. $99ea for the inserts when you can get the hole bar with pins for $150???? I'm just saying.

 

[73m819]

Hmm, sounds like I am wrong. I am going on an experience Wehring and I had where a collared insert was incompatible with an older med towbar. The legs had inequal lengths.

NO you are NOT wrong.
There ARE two lengths of the medium tb.
1 -- The older ones WITHOUT collars and old ones with the MWO.
2 -- New ones with FACTORY INSTALLED collars.

I found out this info first hand, I have my tb mount on the outside of my bed, with it hanging from 7/8" pins (long moded bolts), I pulled my old non WMO tb because I came into a NEW tb, went to hang each leg on the pins, only to find out (*^&^%$$^^&*(&^ that the NEW tb was about 1 1/2" TO LONG for the EXTESTING pins, SURPRISE, SURPRISE, I like everybody else thought ALL the mediums were one size fits all.

 

[73m819]

So will a newer collared insert still fit/work in my older non collered bar(s) ???

NO

 

[Recovry4x4]

So now we need to scare up both the modified bar and the factory produced bar and record all of the critical dimensions for a towbar sticky. Memory says that the older bar NSN ends in 6056 and the newer 7094 if.memory is engaged. I have an older bar sans collars I can measure on my next days off. FWIW, the few bars of both designs that I have had, did interchange.

 

[73m819]

So now we need to scare up both the modified bar and the factory produced bar and record all of the critical dimensions for a towbar sticky. Memory says that the older bar NSN ends in 6056 and the newer 7094 if.memory is engaged. I have an older bar sans collars I can measure on my next days off. FWIW, the few bars of both designs that I have had, did interchange.

What critical dimensions are needed, since I have BOTH, I will take the measurements, give me a list of what is needed, then I will post the results.

 

[73m819]

So now we need to scare up both the modified bar and the factory produced bar and record all of the critical dimensions for a towbar sticky. Memory says that the older bar NSN ends in 6056 and the newer 7094 if.memory is engaged. I have an older bar sans collars I can measure on my next days off. FWIW, the few bars of both designs that I have had, did interchange.

This is I would guess is because both ARE old tbs , one with and one without the mwo.

 

[doghead]

I had one leg of an odd one once. I cut a little off the outer tube to make it fit all they way in with the pin.

 

[gimpyrobb]

Eastern Surplus has a pallet of the inner legs, NOS.

Listed on their site.

That was posted here too.

 

[Recovry4x4]

As far as measurements, I would think overall length and hole locations.