EKII Marked KM

[Krist]

Hello,
I bought this EK2 few days ago on Ebay .
I think that these is original ,
but I find it strange that the core in some places is too small .
What do you think of it ?
Desire to conduct you comment .
Thank you .
Regards , Kris .

[gregM]

Perfectly good looking cross.
You can compare it against these----
http://dev.wehrmacht-awards.com/foru...d.php?t=263937

[Miro O]

I agree with Greg, perfectly good and quite desirable KM cross.
The fact the "core is too small" is caused by age, imo.

Miro

[saschaw]

As said, nothing wrong with this cross made by the Stuttgart state mint.

[pzrwest]

I agree with Greg, perfectly good and quite desirable KM cross.
The fact the "core is too small" is caused by age, imo.

Miro

Are you saying the core has shrunk over the years?

[Jesse]

A very nice example, thanks for showing.

Jesse

[Miro O]

Are you saying the core has shrunk over the years?

More likely vice versa - I´d say frame has deformed over the years. Different thermal behaviour of different metals (iron and silver) plays its role here, imo, but I´d rather speak about thermal expansion than about shrinking.

Miro

[Krist]

Hello ,
Thanks everyone for the replies .
Regards , Kris .

[Krist]

More likely vice versa - I´d say frame has deformed over the years. Different thermal behaviour of different metals (iron and silver) plays its role here, imo, but I´d rather speak about thermal expansion than about shrinking.

Miro

It's the first time that I hear of the expansion of the frame of a EK2 .
By what comes this then ?

[Montgomery Burns]

More likely vice versa - I´d say frame has deformed over the years. Different thermal behaviour of different metals (iron and silver) plays its role here, imo, but I´d rather speak about thermal expansion than about shrinking.

Miro

the newest DR Bunson Honeydew theory ?.








.

[SCOTT G]

Very nice KM marked cross looks to be in over all good condition, wouldn't worry about the loose fitting core as this is quite common on 1914 EK2s .What causes it can be a number of things but as it doesn't effect the cross it's not a problem.

[Miro O]

the newest DR Bunson Honeydew theory ?.








.

Hi Kai,

I was wholeheartly awaiting your opinion few days ago, when I posted Koch & Bergfeld cross with sidehooks here on WAF. I was thinking that you, as the founder and the only contributor to the "Study off Koch & Bergfelt" thread, would surely bother to spend a few words about such piece. I was wrong.

So, I am asking myself, why are you not ignoring me now and opening with such dishonest comment...

Surprising to see it from the man, who brought here many crazy theories, that lately appeared either as revolutionary or as totally stupid as well. This is always the risk of bringing theories, isn´t it...

Thermal expansion is quite well known effect that happens in large scale and in extremely small as well and apart from pressure it is the main reason of materials deformation. http://en.wikipedia.org/wiki/Thermal_expansion

Of course, gases and liquids has the biggest coefficient of thermal expansion, but this effect is noticeable also with solids. Mainly products with danger of linear expansion (pipes, rails, bridges) are designed with expansion joints - reserves for thermal expansion. Coefficient for iron at 20°C is 11,8. Silver has coefficient 18, which means silver expands more than iron at same temperature. Other thing, imo, is that frame with its thin and long shape (same as rail track) expands more linearily (and in other directions) than the core with its solid shape.

Naturally, iron cross is not bridge or rail that is able expand in tens of centimetres - and room temperature is not exterior, where the difference can be more than 60°C within a year. But we are speaking about tens of years and about changes not bigger than millimetres.

I quote wikipedia: "Precision engineering nearly always requires the engineer to pay attention to the thermal expansion of the product. For example when using a scanning electron microscope even small changes in temperature such as 1 degree can cause a sample to change its position relative to the focus point."

I´d say average storage temperature of Iron cross (or room temperature if you want) raised between 1914 and 2014 for at least 10°C.

Correct me, if I am wrong, I have no problem with it, but please try to change the style of discussion - there are enough problems with your phonetical english.

Best, Miro

[morel5000]

Hi Miro,


I don't want interfere but
when using the Thermal expansion of 11.8 and 18 um/m then at a total temperature difference of 40 degrees Celsius overtime we will get some length difference between iron and silver of:

dL=dT*(alpha_silver-alpha_iron)*L

where L the length (m), T the Temperature (K or C) and alpha the Thermal expansion coefficient in um/m

40*6.2*0.04 =10 um, micron.

So I guess that eliminates this theory, sorry.

Kind regards,
Michel

[Miro O]

Hi Michel,

Thank you for your input. I think the problem with your calculation is, that iron core and silver frame - thanks to their different shape - has different vectors of thermal expansion. Iron core, as quite thick and consistent piece of iron expands areally to all directions (of course, mainly to the four directions of arms), so the length of core is valid entry, while silver frame - as hollow and thin material behaves like a pipe, or rail track, although "bent" to "cruciform circle", so perimeter of the frame would be more valid entry than the simple length of the frame.

Miro

[morel5000]

Hi Miro,

the order of magnitude as estimated is of no significance.

Best regards,
Michel