Bohler's N690

P

Philip Dunn

Joined
Nov 3, 2015
Messages
5
Good day everyone

I would like to know from all who has any experience with N690. Whether you a knife maker of just a user/abuser. That includes even the haters of this steel. What are your thoughts? Prositives/negatives. All is welcome. I'll apologise in advance if this topic has been covered.
 
Last edited:
Very good stainless similar to VG10

I use it on a regular basis and users seem to love it.

To be honest what I find is actual users of custom knives who put it to use do not really care what the steel is, the just care if it performs.

Collectors who imagine the newest steels are the best steels are usually the picking ones even though the knife will probably only cut paper and shave hair and spend most of its life in a drawer.
 
Philip Dunn said:
Good day everyone

I would like to know from all who has any experience with N690. Whether you a knife maker of just a user/abuser. That includes even the haters of this steel. What are your thoughts? Prositives/negatives. All is welcome. I'll apologise in advance if this topic has been covered.
Click to expand...

Phillip welcome to Blade forums. :)

As you have no doubt discovered many of the South African makers use Bohler N690 extensively. Almost all the SA makers report excellent results with it provided it is heat treated correctly.
Fortunately here in Cape Town Bohler have an excellent facility to do this. This steel has been used in Europe for many years but is only now beginning to find favour in the US as makers like Todd Begg and others have begun using it.

You should come to the Cape Knifemakers Guild Show next Friday (the 13th of November) and you will be able to get all the advice and help you will need about N690.

Cheers

Steven
 
I just did my first batch with it, and I really like it so far. It takes a nice edge.
 
Philip, I use it for hunting knives, it is a good steel but in same price range I prefer 154CM and ATS34, I find that they are more versatile in the realization of the knife and which are sharpened more easily.

______________________-
Riccardo Mainolfi
 
Thank you everyone for your responses. Steven I will definitely go to the blade show next weekend.

Personally I like N690 as well and I do find that it takes a fine edge and there are several other reasons too. However, I also feel or suspect that you are somewhat limited with this steel (class of knife). Maybe I am wrong maybe not or maybe I'm missing something completely. In my experience, N690 tend to chip easy. Especially with very low angles. Low angles increase cutting performance. I am not a metallurgist but from what I understand is that this steel creates huge amounts of carbides, pretty much to the extent that your very edge is nearly all carbide. Carbides tear out and thus all the chipping. Higher edge angles and edge thickness makes it a lot more durable and decreases chipping. But this IMO shortens the life of the blade or it means a regrind will be more often required.

Or is all of this what I have been experiencing the results of bad heat treatment?
 
Philip Dunn said:
Thank you everyone for your responses. Steven I will definitely go to the blade show next weekend.
Click to expand...

Come and find me at the show, it will be a pleasure to meet you. My glass display case is in the one corner of the room.
 
Philip Dunn said:
Thank you everyone for your responses. Steven I will definitely go to the blade show next weekend.

Personally I like N690 as well and I do find that it takes a fine edge and there are several other reasons too. However, I also feel or suspect that you are somewhat limited with this steel (class of knife). Maybe I am wrong maybe not or maybe I'm missing something completely. In my experience, N690 tend to chip easy. Especially with very low angles. Low angles increase cutting performance. I am not a metallurgist but from what I understand is that this steel creates huge amounts of carbides, pretty much to the extent that your very edge is nearly all carbide. Carbides tear out and thus all the chipping. Higher edge angles and edge thickness makes it a lot more durable and decreases chipping. But this IMO shortens the life of the blade or it means a regrind will be more often required.

Or is all of this what I have been experiencing the results of bad heat treatment?
Click to expand...

What knife did you use in N690? What angles were you using and what were you cutting to cause edge damage?

In my experience N690 has performed well. But my experience has been with custom makers. Not a steel suited for machetes but for a knife designed for cutting it performs really well when geometry and all comes together.

N690 is a 440C class steel and total carbide volume can range generally from 10-18 percent depending on austinization, quenching and tempering cycle. The very edge is not all carbide.
 
marthinus said:
What knife did you use in N690? What angles were you using and what were you cutting to cause edge damage?

In my experience N690 has performed well. But my experience has been with custom makers. Not a steel suited for machetes but for a knife designed for cutting it performs really well when geometry and all comes together.

N690 is a 440C class steel and total carbide volume can range generally from 10-18 percent depending on austinization, quenching and tempering cycle. The very edge is not all carbide.
Click to expand...

The knives were kitchen knives and they were heat treated by bohler. Not all have had these problems. On some I've sharpened them down to as low as 10dps and it is then when I've experienced it through general kitchen use and cutting on plastic cutting board. My wife uses the knives as well but she is experienced enough with knives not to do silly stuff with them. I've resharpened to 15dps and it seemed better for a little longer but still little chip and now the knife is on 20dps. It is holding out nicely but the edge is a little on the thicker side measuring 0.48mm at the shoulder of the edge. I have 2 new large chef knives now with edge thickness prior to sharpening at 0.15 mm and 0.18 mm. I gave them a 20dps bevel and will proceed cutting with the intention to see if it'll hold up. It is that exact geometry you mentioned that I'm trying to figure out. Could you explain a bit more about the austinization, quenching and tempering please.
 
Philip Dunn said:
The knives were kitchen knives and they were heat treated by bohler. Not all have had these problems. On some I've sharpened them down to as low as 10dps and it is then when I've experienced it through general kitchen use and cutting on plastic cutting board. My wife uses the knives as well but she is experienced enough with knives not to do silly stuff with them. I've resharpened to 15dps and it seemed better for a little longer but still little chip and now the knife is on 20dps. It is holding out nicely but the edge is a little on the thicker side measuring 0.48mm at the shoulder of the edge. I have 2 new large chef knives now with edge thickness prior to sharpening at 0.15 mm and 0.18 mm. I gave them a 20dps bevel and will proceed cutting with the intention to see if it'll hold up. It is that exact geometry you mentioned that I'm trying to figure out. Could you explain a bit more about the austinization, quenching and tempering please.
Click to expand...

Phillip

I run similar angles and thickness of 0.4mm on my general use knives. No issue with chipping.

I can email you a lot of free papers on the net. Drop me an email. A lot of your questions will be answered when you meet Steven and the people he will introduce you to.

As to why you are experiencing chipping there is a lot of variables within the heat treating process. It can even come down to aspects such as where Bohler places your blade in their furnace and if you do pre heat treat grinding it can cause stress rises and since it is thinner it can cause issues with regards to holding time.

I wish I could give you more detail but I am on my phone and no computer access for some time to reply fully.

I will say this. For a kitchen knife I will rather go powdered metallurgical steel RWL34 (speak to Des Horn about it) if you want similar wear resistance and bring down the rusk of chipping. But for me who hate chipping when it comes to food I prefer a lower carbide steel such as 14C28N or 12C27 but with my own heat treat process or if I really want to push the limits Nitrobe 77 or LC200N.
 
marthinus said:
Phillip

I run similar angles and thickness of 0.4mm on my general use knives. No issue with chipping.

I can email you a lot of free papers on the net. Drop me an email. A lot of your questions will be answered when you meet Steven and the people he will introduce you to.

As to why you are experiencing chipping there is a lot of variables within the heat treating process. It can even come down to aspects such as where Bohler places your blade in their furnace and if you do pre heat treat grinding it can cause stress rises and since it is thinner it can cause issues with regards to holding time.

I wish I could give you more detail but I am on my phone and no computer access for some time to reply fully.

I will say this. For a kitchen knife I will rather go powdered metallurgical steel RWL34 (speak to Des Horn about it) if you want similar wear resistance and bring down the rusk of chipping. But for me who hate chipping when it comes to food I prefer a lower carbide steel such as 14C28N or 12C27 but with my own heat treat process or if I really want to push the limits Nitrobe 77 or LC200N.
Click to expand...

Thank you Sir.
 
You must log in or register to reply here.
Back
Top