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2 Swedish Air Force survival knives

Blade hand reground to it's original full convex blade shape on a Foss 7205 black/green silicon carbide stone used with oil, then refined on 400 grit and 1000 grit SiC wet & dry paper used with oil on glass, and the tiny burr stropped off on hard cardboard with 1.0 micron diamond paste.
The new apex measures between 20 and 22,5 degrees inclusive.
Very hard (guesstimate 64-65 HRC) and also very wear resistant steel.
Handle reassembled, now with all washers glued and pommel repolished, then treated to a few coats of warm Granger's wax.
Sheath waxed and hand restitched.





 
The second knife is a bit worse, also due to the handle's leather midsection which had rotted over time together with a pommel stuck in place.






 
Both Pontus Holmberg knives are made from iron ore from the Dannemora mine, which resulted in very pure steel due to it being rich in manganese.
In earlier centuries it was known as "oregrounds iron": https://en.wikipedia.org/wiki/Oregrounds_iron
However i don't know if that name was still being used by the time these knives were made in the late '40's or early '50's of the 20th century.

Sheffield also used a lot of this same ore to make their famous crucible cast steel from ~1740 up until ~1960.
These two Swedish knives however are noticeably harder as well as much more wear resistant when compared to the vintage English crucible steel knives that i've hand reground/sharpened over the years.
 
Currently busy with making a new leather midsection for the handle of knife # 2:



 
The new leather midsection after rough machine sanding with a cheap Parkside linisher (which i modified so it can do slack belt sanding):


 
The blade has been hand reground on the Foss 7205 combination stone (burr is partly visible), and a few refining steps on wet & dry SiC paper will follow later.
Now regrinding the swedge with 300 and 600 grit diamond files.

 
Regrinding the old jimping / notching using a cordless drill with diamond bit & WD40 oil:

 
How the blade looks after hand regrinding to full convex again on the green silicon carbide side of the Foss combination stone used with WD40 oil.
The new edge angle measures ~20 degrees inclusive.


 
Currently experimenting a bit with different grits of diamond paste on thin cardboard to see what gives both a nice blade finish as well as a good apex.

Already found that only removing the burr is not enough to get the sharpest of edges on this steel, i have to continue stropping a bit to also get the (presumed tungsten) carbides into the right shape.
I also have to tinker some more with the appearance of the blade finish (now it's a bit too shiny for my taste), but the current apex is reverse hairwhittling sharp (chest hair) @ ~20 degrees inclusive.


 
While busy with finetuning the handle the knife slipped out of my rubber coated vise and fell from a measured hight of 1.10 meter on one of the concrete sidewalk tiles which form the floor on my balcony, and landed on the belly part of the edge.
I did not try to catch the falling knife :)

To my surprise there was only slight denting in that area, no large chips, which i would have expected given the presumed high hardness in combination with the narrow edge angle.
Anyway, due to this i had to regrind the blade again on the green silicon carbide side of my Foss 7205 stone, and that is where i am now.


 
petroman zei:
Maar waarom in het Engels??
Klik om te vergroten...

Ik heb geen Engels lessen gehad net als een paar anderen op dit forum, beste @petroman en @kwakster daarom slaan we dan de Engelse berichten over of moeten het vertellen via Google vertaling, wat ook nog eens geen goed vertalingen geven.
Ik hoop dus nog meer te kunnen genieten van jullie berichtjes in het Nederlands.
Haha als jullie echt zo goed zijn in talen misschien kunnen de stukjes van als nog vertaald worden, alvast hartelijk dank daar voor.
 
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Een hele dikke compliment voor het prachtig mooi maken van de oude mes Top gedaan.
 
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