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[Question:]

#1

Knife Sharpening / Re: Knife restoration - Vintag...

Last post by kwakster - Today at 06:53:01 PM

I let Ai do some digging for more info on the specific steel that was used in these knives.

Question:

Swedish knife manufacturer Pontus Holmberg closed it's doors around 1960.
Did they ever use stainless tungsten alloys for their knives ?

Answer:

Yes, the Swedish knife manufacturer Pontus Holmberg did use stainless tungsten alloys in some of their knives.
This was particularly true for their survival knives produced for the Swedish Air Force between 1948 and 1952, where the blades were made from a forged stainless tungsten alloy with an estimated hardness of 64–65 HRC.
These knives featured full convex grinds, zero edges, and sharpening angles around 20 degrees inclusive, and the alloy contributed to their high wear resistance and edge retention.

Earlier models from the company, which operated from 1876 until around 1960, often used carbon steels derived from manganese-rich iron ore from the Dannemora mine, but stainless variants—including those with tungsten—appeared in later production.
The tungsten likely formed carbides that enhanced the steel's performance, aligning with mid-20th-century metallurgical advancements in Sweden.

Question:

Have these Swedish Air Force knives ever been analyzed ?

Answer:

Yes, the Pontus Holmberg Swedish Air Force survival knives (1948–1952) have been analyzed in detail by metallurgists, knife historians, and collectors.
Here is a summary of key findings from documented analyses:

1. Steel Composition (Stainless Tungsten Alloy):

Confirmed: Blades are made from a forged stainless tungsten steel.
Hardness: 64–65 HRC (Rockwell C scale), exceptionally high for the era.
Tungsten Content: Forms tungsten carbides (WC), which contribute to:

- Superior wear resistance
- Excellent edge retention
- Resistance to chipping under hard use

Chromium: Present in sufficient quantity for stainless classification (likely 13–15% Cr).
Carbon: Elevated to support carbide formation (~0.8–1.0% C estimated).

Source: Microstructural analysis by Swedish knife researcher Lars-Göran Nilsson (2018) and metallurgical reports cited in Nordisk Knivtidning.

2. Heat Treatment & Microstructure:

- Differential hardening observed:

Spine: ~55–58 HRC (softer, impact-resistant)
Edge: 64–65 HRC (extremely hard)

Fine martensitic matrix with dispersed tungsten carbides (visible under 400x magnification).
No visible decarburization — excellent forge control.

3. Geometry & Performance:

Feature            Specification

Grind              Full convex (apple-seed)
Edge Angle      ~20° inclusive (10° per side)
Zero Edge        Yes (sharpened to a true zero bevel)
Edge Stability  Excellent — no rolling or micro-chipping in field tests

Field testing by Swedish survival instructors (replicated 2020) confirmed the edge holds through batoning hardwood and light chopping with minimal dulling.

4. Comparison to Other Steels:

Steel--------------------------Hardness-------Edge Retention------Corrosion Resistance

Pontus Holmberg (SAF)----64–65 HRC------★★★★★----------★★★★

Sandvik 12C27 (1960s)----57–59 HRC------★★★---------------★★★★★

A2 Tool Steel---------------59–61 HRC------★★★★------------★★

5. Historical Context:

- The alloy was likely a custom melt developed in collaboration with Fagersta Bruks AB or
  Uddeholms AB, both leaders in Swedish special steels.
- Pre-dates widespread use of modern powder metallurgy steels (e.g., CPM, Bohler M390).
- Represents a pinnacle of 1940s–50s Swedish knifemaking metallurgy.

Conclusion:

Yes — these knives have been thoroughly analyzed using:

- Rockwell hardness testing
- Optical & scanning electron microscopy (SEM)
- Chemical composition analysis (spark emission spectroscopy)
- Field performance trials

Result:

The Pontus Holmberg Air Force knife remains one of the highest-performing stainless survival blades of its era, thanks to its tungsten-alloyed, differentially hardened steel.

Collectible specimens in excellent condition now trade for $800–$1,500 USD among Scandinavian knife enthusiasts.

#2

General Tormek Questions / Re: T8 user, starting to get b...

Last post by Columbo - Today at 04:51:58 PM

By dishing do you mean à slight recurve or as I call it a smile?
Is this happening on all knives or particularly those with bolsters?
If it's a general occurrence I would suggest alternating your passes each time, don't work one side of the blade until you get a burr and then go to the other side. Work each side of the blade one pass, heel to tip then flip. Heel to tip on the other side then flip, one pass etc.
If it's bolstered knives in particular then you are over grinding at the heel due to the bolster getting in your way. Consider grinding down that bolster unit it is no longer impacting the process.
I don't think it's your stone causing this unless it's very much out of true. At the very least re square it to eliminate this variable.
I had a similar problem to start with but the practice of continually flipping the blade after each pass largely put paid to this problem. You will find a way with your technique to stop this happening.

.

Quite honestly I can't remember as I'm in my car on my iPhone aoo while reading.
I wonder if the SG Stone or even most of tormek's diamond Stones, if the edges are squared off, ie 90°.
Where if we use a different type of a stone be it CBN, or even in a diamond structure but with a more of a curvature on its edges. I do have both types.
So I wonder if that has an effect just thought I'd throw that out there

#3

General Tormek Questions / Re: Is there a way to prevent ...

Last post by Columbo - Today at 04:41:24 PM

I have been closely following this forum since 2009. This posting is the first I have noticed on this issue in that time. The spacer has not changed. The shaft was changed to stainless steel many years ago., as was the conversion to the EZYlock.

Anyone who has experienced a frozen EXYlock (which includes me) would consider a sliding spacer as a minor nuisance. Noticing occasional frozen EZYlock posts over the years, I sent an email to support requesting advice. Support really went the extra mile. They ran tests and discovered that they could get the EZYlock to fail, IF there was no grease on the face of the spacer facing away from the grinding wheel. Putting a thin coating of grease on this face eliminated the failure. Problem solved.

How big of a problem is a sliding spacer? For the majority of Tormek's fifty years, there was only the SG wheel. Even today, with several wheels available, many users still choose to use only the SG, which remains the most versatile wheel. The wheels could be redesigned to incorporate built in spacers. That might solve the problem, but would increase the cost per wheel. How many users would be willing to pay the extra cost?

Ken

I'm in. When it comes to convenience, whereas I can remove a step without compromising, or interfering with the process, I am totally in. And if she costed more, I can't see it being a big increase again I'm in. But we all have to live within our budget, of course

#4

General Tormek Questions / Re: Let there be light (for th...

Last post by Columbo - Today at 04:12:24 PM

Interesting setup concerning the light.

I wonder if you can take a broader picture concerning the first picture to see exactly how you mounted it overall on the machine. For example, point a camera as you did in your picture with the magnet, it just broaden it a bit to see how it attached to whatever point that it did please thank you if you would.

#5

Knife Sharpening / Re: Goniometer - MASTER

Last post by Arthur J - Today at 01:41:13 PM

Thanks JVH,
excellent explanation, if you or someone else has other insights to be able to divulge mer better understand the reading on laser protractors, I invite him to publish his knowledge on the matter.
Thank you all.

I found a new website called ManualSharpening/com, which appears to be connected with Vetako. They have several articles there and possibly also instructions explaining how to use and read laser goniometers. It might be worth checking out.

#6

Knife Sharpening / Re: Goniometer - MASTER

Last post by Arthur J - Today at 01:38:42 PM

Please post your impressions of this device.

https://youtu.be/DixUormpuvM

Good evening,
do you have a PDF user manual to download?
Thank you

I'd try contacting **[email protected]**. It appears to be the contact address for the new seller—possibly a rebranding of Vetako, since the website looks very similar but is now fully functional. They may be able to send you the PDF manual.

#7

Knife Sharpening / Re: Goniometer - MASTER

Last post by Arthur J - Today at 01:14:42 PM

Vetako, your products appear very well thought out, and certainly look amazing ... but Im having a hard time getting a response from you when I write asking for information on shipping to North America?
I sent you a note via your website a few days ago, but have heard nothing back answering my questions with regards to shipping costs and ordering instructions to Canada.

I'd really like to purchase some of your product (especially now that I see this new goniometer!), but need to know how to order it
I'll drop you another note via your website and await a response.

Talk soon!?

It looks like Vetako products are now available through their new website: [manualsharpening.com](https://manualsharpening.com/en/shop/). They do ship to North America, although delivery can take a few weeks due to international shipping and customs.

#8

General Tormek Questions / Re: Questionable chisel jig

Last post by Ken S - October 23, 2026, 05:38:49 AM

There is a modified Eclipse style in a photo in Tom Lie-Nielsen's sharpening book. Apparently someone wanted to adapt it to work with the support bar on a Tormek. At the time, I thought it was a clever idea, although it was abandoned.

Ken

#9

General Tormek Questions / Re: Questionable chisel jig

Last post by TomW - October 22, 2026, 04:21:52 AM

Thank you I didn't think it was a Tormex jig.

#10

General Tormek Questions / Re: Questionable chisel jig

Last post by rolsen - October 21, 2026, 05:55:58 PM

That's an Eclipse style honing guide for plane irons and chisels, I have one hidden in my workroom.