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Armor/AFV: Axis - WWII
Armor and ground forces of the Axis forces during World War II.
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Help with this detail - German Leaf Springs
165thspc
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Posted: Monday, July 17, 2017 - 02:05 AM UTC
German Leaf Springs

I'm always careful to clean the mold lines off the leaf springs on any WWII vehicle I might build. However, perhaps I've been overdoing it, at least on the German vehicles?

Anyone know the real story regarding these seam lines on the leaf spring under this German generator trailer? I first noticed a similar seam line on the front axle leaf spring of the FAMO that was restored by Kevin Wheatcroft in England about ten years ago.

As far as I can figure, the Germans must have run their spring stock thru some sort of rolling mandible that put a ridge/crease down the center of the individual leaves. I suspect this increased the maximum load weight the spring could handle and reduced any tendency for the leaves to work out of alignment.

Anyone have more info?

Thanks

Mike Koenig Photo

p.s. On my model FAMO I still cleaned this line off anyway b/c I feared a judge would mark me down for not properly cleaning this very visible part.
petbat
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Posted: Monday, July 17, 2017 - 02:38 AM UTC
Hi Michael

I have seen this on a Famo like you are talking about, is it this one:


However, you just can't be sure if they are original components or not.

Museums often replace parts or fabricate them, and they are not identical to the originals. Same goes for restorations. However, if you look at various clips of WW2 German Half-track vehicles dragged out of bogs, etc, once cleaned up, there are no ridges on the vehicles that I have seen.

This doesn't mean the ridge is not genuine, it could be specific to a particular manufacturer of a specific vehicle component, etc.

It would be wonderful if they were all like that though, less clean up for us.

165thspc
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Posted: Monday, July 17, 2017 - 02:40 AM UTC
Detail of Front Transverse Leaf Spring on the Wheatcroft FAMO Sd.Kfz. 9:


Photo used here for discussion only.
165thspc
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Posted: Monday, July 17, 2017 - 02:54 AM UTC
Thank you Peter, that is a FAMO alright. And if you will notice, it has the same seam line on the front leaf spring as the others.



Today they still make custom leaf springs for special heavy equipment and to restore antique vehicles. For this they use flat or curve formed spring steel leaves. If this were a modern reproduction leaf spring it would definitely not have the seam.
165thspc
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Posted: Monday, July 17, 2017 - 03:00 AM UTC
Here is a set of very used heavy Mack truck rear leaf springs. They could be 60+ years old or manufactured yesterday. The Mack design has not changed appreciably, and no seams here.



It is my suspicion that the FAMO spring is a typical example of the German tendency to over-engineer everything. A lot more manufacturing effort and complexity for a slight improvement in performance.
165thspc
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Posted: Monday, July 17, 2017 - 07:44 AM UTC
As an interesting (perhaps) contrast to the FAMO; I checked my files on the Sd. Kfz. 10, Demag D7, a small 1 ton German halftrack. For whatever reason the Demag DOES NOT have a seam on the front leaf spring.

-
Both photos copyright Michael Koenig 2004

Down through the years I have had close access to three different D7 Demags but this is the only one I photographed in such detail. This spring looks so new and perfect it COULD be a modern replacement. As to the other vehicles, unfortunately I never looked close enough to know one way or the other.
165thspc
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Posted: Tuesday, July 18, 2017 - 06:17 PM UTC
Based on the limited responses I have gotten, I guess I must have pulled a really tough question out of the old German wartime vehicle shop?
Frenchy
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Posted: Tuesday, July 18, 2017 - 06:54 PM UTC
This FAMO has them as well :





H.P.
165thspc
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Posted: Tuesday, July 18, 2017 - 07:43 PM UTC
I can understand a transverse mounted leaf spring needing something extra to keep the leaves aligned as it is subject to a lot of left/right twisting as the front axle hits uneven road bumps.

I was very surprised however to find the same design on the little generator trailer and even more surprised to find this detail missing on the front spring of the little Sd. Kfz. 10.
Frenchy
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Posted: Tuesday, July 18, 2017 - 08:22 PM UTC
It's missing on this Sdkfz 251 Ausf A as well :

http://data6.primeportal.net/apc/paul_adamson/sdkfz_251_ausf_a/images/sdkfz_251_ausf_a_04_of_66.jpg

Same on this Sdkfz 7 :

http://www.net-maquettes.com/fr/pictures/sdkfz-7-walk/?afg66_page_id=5#afg-66

and this Sdkfz 8 :

http://www.britmodeller.com/forums/index.php?/topic/235003498-sdkfz-8-sonderkraftfahrzeug-8-german-halftrack/

H.P.
m4sherman
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Posted: Tuesday, July 18, 2017 - 10:46 PM UTC

Quoted Text

I can understand a transverse mounted leaf spring needing something extra to keep the leaves aligned as it is subject to a lot of left/right twisting as the front axle hits uneven road bumps.

I was very surprised however to find the same design on the little generator trailer and even more surprised to find this detail missing on the front spring of the little Sd. Kfz. 10.


I don't have the depth of references that Frenchy has! However, after looking at all the pictures I did notice a couple things of interest.

The Famo and generator springs look like they were manufactured by the same source. All the springs are the same thickness, have rounded edges, and seem to have a slight taper to the outside, that could be an optical illusion (but I've seen the taper on other 1940's era springs).

On the 251 the springs are all thicker and flat, with rounded edges.

On the Sdkfz 7 and 8 there are thicker springs for the top few springs, typical of overload springs, with thinner springs for the rest of the leaves. Again with rounded edges and a flat surface.

Generator trailers may be small, but can also be heavy due to the engine and generator installed. I counted 10 leaves, which is about the same for my WWII Willys, which has thicker/thinner leaves like the Sdkfz's.

Perhaps the ridges are there to compensate for the thinness of the springs, and the lack of the thicker overload springs.

Who built the Famo's and did they also make other half tracks?
CReading
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Posted: Wednesday, July 19, 2017 - 04:56 AM UTC
Do the 'ridges' have corresponding 'grooves' on the underside of the spring? If so, perhaps it's purpose is for alignment? Keeping the springs from moving side to side?
Good thread and topic ! And I thought I'd seen every little detail scrutinized where German vehicles are concerned

Cheers,
C.
petbat
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Posted: Wednesday, July 19, 2017 - 05:27 AM UTC

Quoted Text

Do the 'ridges' have corresponding 'grooves' on the underside of the spring? If so, perhaps it's purpose is for alignment? Keeping the springs from moving side to side?
Good thread and topic ! And I thought I'd seen every little detail scrutinized where German vehicles are concerned

Cheers,
C.


Based on the generator trailer pic, where one leaf is bent down 90 degrees behind the retaining bracket, it is likely they were grooved, so you may be onto something - especially given the number of springs secured only in the centre.

Just when you thought it was safe to go into the water...... It just goes to show you how little we really do know about the small details. The arguments still rage about red fire extinguishers, whether the tube rear lights were green or blue etc...and now grooves on springs
bill_c
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MODEL SHIPWRIGHTS
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Posted: Thursday, July 20, 2017 - 03:39 AM UTC

Quoted Text

...and now grooves on springs

Headhunter506
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Posted: Thursday, July 20, 2017 - 04:28 AM UTC

Quoted Text

The arguments still rage about red fire extinguishers, whether the tube rear lights were green or blue etc...and now grooves on springs


The convoy light tube color debate had been settled about five years ago. It was green:

Blue tail light late war fitting - more thoughts







There are grooves on the undersides of the leaves for exactly what Charles mentioned - aligning the leaves, preventing side-to- side movement and twisting. The grooves are visible in the photos previously posted.
brekinapez
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Posted: Thursday, July 20, 2017 - 06:03 AM UTC

Quoted Text



The convoy light tube color debate had been settled about five years ago. It was green:

....

There are grooves on the undersides of the leaves for exactly what Charles mentioned - aligning the leaves, preventing side-to- side movement and twisting. The grooves are visible in the photos previously posted.


Nailed it.
DocEvan
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Posted: Thursday, July 20, 2017 - 06:14 AM UTC
The problem is that most people do NOT expect seams on things like this. But, it's YOUR model...build it the way you want!
Headhunter506
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Posted: Thursday, July 20, 2017 - 06:24 AM UTC

Quoted Text

The problem is that most people do NOT expect seams on things like this. But, it's YOUR model...build it the way you want!


Any rivet counter worth his salt would.
brekinapez
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Posted: Thursday, July 20, 2017 - 06:30 AM UTC

Quoted Text

The problem is that most people do NOT expect seams on things like this. But, it's YOUR model...build it the way you want!


Strange thing is, I've seen a few build logs and kit reviews in the past where the reviewer pointed out that the seams on some of these parts were meant to be there and not to remove them.

So maybe it is most people NOW do not expect seams.
165thspc
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Posted: Thursday, July 20, 2017 - 05:07 PM UTC
Fired off an e-mail last night to the "Spring Guru" at Detroit Eaton. We will see what kind of answer we get back from him regarding German seamed leaf springs.
165thspc
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Posted: Monday, July 24, 2017 - 09:56 PM UTC
Some "Springly Wisdom" from the Detroit Eaton "Spring Guru":

Many springs were made this way, not only the Germans. I do not know of any special name for springs made like this.

Thank You

EATON Detroit Spring, Inc.
Phone 1-313-963-3839
Fax 1-313-963-7047
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