Messages

@aquataur

Yes, it is clear that ordinary cutlery steel is not suited for thinning, it will not last long, but I did not want to ruin expensive Japanese knives straight away and needed some practice

That said 14C28N turned out to be much better than I expected and in the end I like it better than VG10 for instance because it does not chip easily and keeps an edge

Hi Antonio,

No, the idea is to get a "perfect V" profile without secondary bevel, so when there is one (that was the case for example of knives with scandy grind) I got ride of it, removing material that had been untouched.

For blades where the profile was more a "U" then a "V" I reshaped it entirely, basically as if it was a new blade that I had to grind from blank.

With he diamond wheel it is quite fast and since the wheel does not wear out as much as a natural or synthetic stone it is only a matter of doing the same on both sides (and this is why I count the number of passes).

So, again, when facing the machine, I place the blade pointing away from me on the circumference of the wheel (although there are diamonds on the sides of the grinding wheel I did not use them) and I go back and forth (i.e., not with the blade moving left-right parallel to the shaft, as Tormeks are normally used)

@Merlin

I continued my thinning experimentation and played with an Ikea 365+ knife, the blade is 20cm long, and the entire knife is made of X50CrMoV15 which is a "German-style" steel with HRC~56. That worked well, but the steel is too soft, and having made the cutting edge very thin means that it gets bent/wobbly very fast

So I decided to move to a santoku knife kit with a 16cm blade nearly finished (and already hardened) and wood scales for the handle. I selected this particular model because it used Sandvik 14C28N and was supposed to be HRC~59.

Then I purchased a diamond grinding wheel: what a difference that makes!

Now I can do in 20-30mn what used to take several hours on a standard SG-250 wheel, without having to true it or to worry about where the blade touches, and the result is fantastic.

The "brushed" finish is very uniform and I am tempted to leave it instead of "finishing" the blade with finer sandpapers, but the most amazing is what difference this slightly harder steel made: I never had a kitchen knife so thin before, and this thing is insanely sharp, and it kept its edge so far, a real pleasure to use.

So I can confirm it is possible to make very thin knives with a Tormek, preferably a diamond wheel (which make a beter and faster job at it), and I recommend steel with a hardness approaching 60 HRC

@Merlin

Sorry if I was not clear: I do not use the sides of the wheel but the usual circumference after having made sure it was perfectly true (using the Tormek Truing Tool TT-50)

@merlin:

I am also trying to thin knives on a Tormek at the moment

I started with knives which had a standard "scandinavian" grind (like Mora knives), in carbon steel, and did that with the blade held parallel to the wheel (i.e., not perpendicular, as when sharpening it), little by little, by hand

That sort of worked, the problem is the area close to the ricasso for which I had to rotate the blade 90 degrees, and then somehow "smooth" the transition (and finish with sandpapers)

I now plan to do something similar with a Japanese style knife which does not have a ricasso at all, so in principle it should be easier

Is it this kind of thing you have in mind Rotary tumblers ?

In the end I did not find any local machine shop willing to make the modifications, so I ended up cutting myself 2 large "washers" from a 2mm thick aluminum plate (old computer case) with a ~45mm hole saw cutting drill bit, and that works perfectly.

The stone has a very small wobble, so next I have to reshape the bore to 12mm (with epoxy?) since the original hole is ~20mm and the two bits of plastic reducers do not hold the stone firmly enough

Slow progress, but I will get there

Hi,

Finally I managed to find a natural Gotland stone barely used, close to 250mm in diameter and 50mm wide all the way (without the recess of the "modern" Tormek stones at the bore).

I tried it on a T8 and it fits, however the shaft is now flush with the surface of the stone, and there is no thread left for the EzyLock.

Is there a way to find a longer shaft?

What other solution would you suggest?

LeU

I was looking into CBN wheels also, and actually the text @JohnHancock refers to (I can only see the abstract of the article) says:

In air, CBN forms a stable layer of boron oxide that prevents further oxidation up to 1300°C. However, this layer dissolves in water, so CBN wears more rapidly when water-based fluids are used than with neat oil fluids.

This made me wonder: has anybody here used oil instead of water, even with a standard SG wheel and would there be any benefit in doing it?

Nice to see that it works

A long time ago I tried to contact the company who still makes and sells it nowadays, but they never answered

I think that I saw pictures of a version of this machine which had some kind of honing material in the form of flat disks on the sides of the stone (not on the periphery, as in your setup)

It seems that there is enough space in the water trough for a lot of stuff, but I was wondering. is the motor powerful enough? and is it noisy (with this gearbox)?

@a9cad: What do you think of the gearbox & mechanism driving the wheel of the Kiruna compared to the Tormeks?

I missed the various Tormeks which were on sale, sold too quickly

However there is a Kiruna-slipen which seems interesting (Kiruna-vatslip-275-pro-230v)

It is also a slow water cooled machine (60 revolutions per minute), with a stone which it slightly larger than the SGs (275mm x 50mm) and a smaller/faster grindíng stone instead of the honing wheel

This one is a Pro version, so exactly like the one on this picture, without any jigs but with a stand, it is quite old/dirty although has not been much used:



do you guys know anything about these machines ?

Welcome to the forum, LeU
...
Ken

Thanks Ken
I was aware of the non-stainless steel shaft on the SuperGrind, but I did not know about these T3 overheating issues
Are there other things I will have to pay attention to when buying second hand?

So, (in all seriousness), why not take advantage of what a modern stone might offer also? 

What advantage do you think an old grindstone would have?

Too sentimental I guess?
I liked sharpening knives and axes on these old stones, the feeling of it, the smell., etc.
I never found the same sensations on a bench grinder
This is why I want to have a go as a Tormek
Obviously if I cannot reuse an old stone I will switch to an SG-something, but I would like to try first

Hi Guys,

I just joined this forum because I am about to get a second hand Tormek, I do not know which model yet, since I have not see them physically, but there are several for sale in my area at the moment: SuperGrind 2000, T3, T4 and T8.

When I was much younger I used to play with an old manual grindstone, and I would be happy to retrieve something similar now, taking advantage of what a modern Tormek can provide.

I would like to know if any of you have experience using natural stones with these things, and in particular re-shaping a larger stone make it 200 or 250mm in diameter (depending on the machine)?

Is that feasible at all? will the old stone simply crumble to pieces? how would you cut it?

Looking forward to getting feedback and advice,

LeU

(this is the kind of natural stone I have in mind: https://imgur.com/a/GRDa2RO)