I am very new with the Tormek.
My Tormek T8 arrived last Friday.
curieus I am how your folk are thinning down kitchen knives with the Tormek.
Please tell me your strategy, how your people doing it.
Greetings,
Merlin
The Netherlands.
Hello Merlin,
for a start I would watch in YouTube "Common Tormek mistakes in knife sharpening" by Knife Grinders Australia and the "Tormek Live Sharpening Classes".
Have fun!
Drilon
I indeed did.
Hope to gain more information with my question above...
Merlin
One more question.
Do you know a person who successfully thinned out a kitchen knife with a Tormek?
This would be a starting point, at least.
I'm using a series of flat diamond flat whetstones for that purpose and at the end the task of providing a nice finish is due.
Unless I'm missing something I don't think it's possible to thin knives on the top of a Tormek grinding wheel : you would hollow grind it and would not be able to grind at a low enough angle if the knife is in a jig. The jig would bite into the stone.
Theoretically you could use the side of a diamond or CBN wheel but I think it would be extremely difficult, either free hand or using the MB 100(?), this would require a knife jig to hold the knife and it would still catch on the stone.
Someone else may be more enlightened than me and suggest a way to do it.
I just can't see how a Tormek can be used to thin knives.
Once I tried to flat grind a scandi knife on the side of a diamond wheel free hand. It was a disaster!
Yes that MB 100 option might be a start.
I do know that Japanese Knife grinders use water wheel with huge diameters.
https://www.youtube.com/watch?app=desktop&v=aU6u80Hyw5Y
All Right let's change the question in: Who successfully thinning kitchen knives on the Tormek ?
I just found this video on the Tormek channel.
This knifemaker seems to thin out (makes the shape) of his knives on the side freehand with diamond wheels.
Quote from: Merlin on September 13, 2023, 02:42:38 AMAll Right let's change the question in: Who successfully thinning kitchen knives on the Tormek ?
I am. Look up my recent threads.
Quote from: aquataur on September 13, 2023, 04:59:47 PMQuote from: Merlin on September 13, 2023, 02:42:38 AMAll Right let's change the question in: Who successfully thinning kitchen knives on the Tormek ?
I am. Look up my recent threads.
I will ! Thanks !
M
I also dit it for several knives where I wanted to to it very carefully. There is usually less metal to be removed for thinning down a knife than for repairing a damaged chisel, so I don't see why not.
The angle issue might arise for short (pocket ?) knives with a very low thinning angle.
As for the hollowness, even though it will be more pronounced than for the edge, I don't think it would be an issue for standard (not too thick) kitchen knives, it will even help slightly when restoring the edge with a rod. It will be for thick knives.
Plenty people have terribly cheap kitchen knives.
Very often I get some in my hands that must be ultra cheap warehouse knifes. I don´t have a picture of one of them, but they are immediately recognizable by their huge relief bevel. I suppose this is meant to give the illusion of a much higher quality Japanese style knife.
This relief bevel is hollow, maybe not as pronounced as a 200-250mm wheel would give, but still clearly hollow.
Those don´t have a bolster, but end up towards the handle with a ca. 1cm portion that is blunt.
Don´t believe that you cannot get them to a useful sharpness - you can.
Unfortunately the first time you re-sharpen them the cutting edge gets inevitably hollow near this blunt portion and you have to think about a solution for that.
So those are sharpened on the circumference of some wheel and thus hollow.
I tried this procedure on some of my knifes but the sharpening angles are so low that you very quickly run into the jig´s holding brackets.
Grinding free-hand is a desaster, because you cannot hold still enough to get a nice bevel line. At least I cannot, somebody may have mastered this.
I have seen a guy (was it schleifjunkie?) who has made a special jig for this using magnets, but I abandoned the notion in favour of face-grinding (on the side of the wheel). This works very well for me basically (despite what our quasi-standard "Wootz" encountered), but opens up another pandora´s box. I have written about that galore on my recent threads.
I still adhere to that, because on some point, particularly after repeated re-sharpening, you have to thin the knife, until further perspectives appear.
@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
@LeU
My intention is also to thin done my Japanse kitchen knife on the side of the diamond wheel.
But first q bit more research.
I sharpened for many years on bench stones that works but takes, depending on the steel at least an hour, polishing not included.
M
@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)
Quote from: LeU on September 21, 2023, 06:44:01 PM@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)
Ah I see.
Thank you for the clarification.
M
Quote from: Sir Amwell on September 13, 2023, 12:06:07 AMUnless I'm missing something I don't think it's possible to thin knives on the top of a Tormek grinding wheel : you would hollow grind it and would not be able to grind at a low enough angle if the knife is in a jig. The jig would bite into the stone.
Theoretically you could use the side of a diamond or CBN wheel but I think it would be extremely difficult, either free hand or using the MB 100(?), this would require a knife jig to hold the knife and it would still catch on the stone.
Someone else may be more enlightened than me and suggest a way to do it.
I just can't see how a Tormek can be used to thin knives.
Once I tried to flat grind a scandi knife on the side of a diamond wheel free hand. It was a disaster!
Actually this is exactly how many Japanese forged kitchen knives are shaped after forging but they generally use a larger radius wheel than the Tormek which will further reduce the hollow grinding. I have done it and it works but take care to avoid the apex of you will take out big pieces. Also rocking the blade a bit will effectively grind flat although there will be some inevitable high and low spots. This can be cleaned up on 220 grit waterstones if needed to give perfect flat or convex.
@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
Out of curiosity, what is the coarseness of the diamond wheel you used ?
Quote from: LeU on October 10, 2023, 05:23:42 PM@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
I'm curious how you did it. Did you grind a sort of Primary/Secondary bevel?
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)
The majority of cheap kitchen knives is made out of stainless steel with a composition that varies minimally from the above quoted.
An attempt to shape them like you did, LeU, is prone to fail from a start.
They are very forgiving to mistreatment however. You can make them usefully sharp and they are cheap. Perfect for the average housewife.
Hard steels inevitably are susceptible to rust and are non forgiving. So there is no clear vote for either of them.
Not everybody wants to drive and maintain a Ferrari.
@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
I have a hard steel core clad with stainless. Looks and works great and comes very thin to start with.
Best of all worlds for starters.
Unfortunately (for the part in me that is eager for the stone) it will take a looong time until this one needs some serious maintenance.🙄
Quote from: LeU on October 11, 2023, 06:13:37 PMHi 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)
That's interesting!
How is the result aesthetically? Did you consider the idea of finish everything with a fine bench stone?