RTAK ii 1075 now?

lobo9er

lobo9er

Joined
Jan 5, 2013
Messages
732
Rtak ii was 5160 wasn't it? If it has changed has anyone used both, any differences? Good or bad?
 
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It was being offered in 5160 and a 1095...if it went 1075, the formula if 1075 they use is made for better heavy shock work at the cost of needing a small bit of more sharpening. See Pocket Knife Jimmy (The under glass imprisoner of great knives!) thread on the 1075 switch.
 
As of November 5, 2021 Ontario shows the RATK 2 with 5160 from Instagram. I doubt the steel has changes from then to now.

 
I was responsible for the change of steel for the RTAK II from 1095 to 5160 at Ontario Knife Company, I had introduced 5160 steel to Ontario when I designed the Spec Plus Gen IIs. I had been forging and testing knives from W-1, W-2 and 1095 for years when I started working on longer blades and decided that I needed a tougher steel to survive the stresses to which a longer blade would be subjected. I consider the primary failure in a blade is breaking and wanted to focus my experimentation on preventing this failure. I made blades and tested them in 1060, 1075, 5160 and 6150 and found that they were all "tougher" than the higher carbon steels and, to my surprise, cut as well or slightly better than the higher carbon steels (tested on manila rope, hard and soft woods and a variety of flexing tests involving a vise and cheater bar). When I arrived at Ontario in 2007 I was presented with some RTAK IIs which had a variety of fractures through the blades and thumbnail fractures along the edges. The RTAK II has a wonderful blade geometry for cutting and slicing and I didn't want to change that so I suggested changing the material to 5160 with the heat treatment I developed in my shop. Some years before I had added a couple of digitally controlled kilns and built an agitated quench tank for my shop and performed and documented a series of physical tests and metallurgical examinations on each steel mentioned above and found the optimum performing microstructures for each steel. When Ontario did change the steel to 5160 the fracturing problems ended and ultimately Ontario decided to consolidate their steel uses and switched to the blade steel to 1075 (also no fracturing problems) so the RTAK IIs are currently made from 1075. I am currently working on an article which will tell the history and reveal the reasoning behind the decisions which will be available on the Ontario Knife Company website fairly soon.
 
Dan Maragni said:
I was responsible for the change of steel for the RTAK II from 1095 to 5160 at Ontario Knife Company, I had introduced 5160 steel to Ontario when I designed the Spec Plus Gen IIs. I had been forging and testing knives from W-1, W-2 and 1095 for years when I started working on longer blades and decided that I needed a tougher steel to survive the stresses to which a longer blade would be subjected. I consider the primary failure in a blade is breaking and wanted to focus my experimentation on preventing this failure. I made blades and tested them in 1060, 1075, 5160 and 6150 and found that they were all "tougher" than the higher carbon steels and, to my surprise, cut as well or slightly better than the higher carbon steels (tested on manila rope, hard and soft woods and a variety of flexing tests involving a vise and cheater bar). When I arrived at Ontario in 2007 I was presented with some RTAK IIs which had a variety of fractures through the blades and thumbnail fractures along the edges. The RTAK II has a wonderful blade geometry for cutting and slicing and I didn't want to change that so I suggested changing the material to 5160 with the heat treatment I developed in my shop. Some years before I had added a couple of digitally controlled kilns and built an agitated quench tank for my shop and performed and documented a series of physical tests and metallurgical examinations on each steel mentioned above and found the optimum performing microstructures for each steel. When Ontario did change the steel to 5160 the fracturing problems ended and ultimately Ontario decided to consolidate their steel uses and switched to the blade steel to 1075 (also no fracturing problems) so the RTAK IIs are currently made from 1075. I am currently working on an article which will tell the history and reveal the reasoning behind the decisions which will be available on the Ontario Knife Company website fairly soon.
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Fabulous! Can't wait to read your article. Dan, you are one of the demi-gods of steel! I'm glad Ontario is still active on here. For awhile now, it's been like waiting for a new star to show up in the night sky.

With the sale of Cold Steel to a big corporate conglomerate and their resulting issues, I'm hoping Ontario will take up the slack in the realm of great hard use knives. Ontario's always had very reasonable prices and they're made in USA. There's a void in the categories of big, heavy duty knives and tactical knives that Ontario could fill in.

I've used my RTAK2 in 5160 steel for about the last ten years to chop and clear thick brush and wood. It's performed extremely well and held up to abuse that would have broken a lesser knife.
 
Yes, Welcome Dan, I've heard many good things about you and your knife knowledge in the past. 👍
 
My RTAKII works horribly around here! But that's because of the type of vegetation not the knife's problem. :D
The SP-10, 51 and 53 work better on black spruce and alder brush.
:D
 
I have a Livesay RTAK, in 1095, that I bought from Newt personally nearly 20 years ago. It's seen some hard use, and is my favorite big brush knife. I've had no issues with his differential heat treatment, and consider it a good knife, within its limits. The blade is designed more for woody vegetation than hardwoods, and was favored by DEA agents for marijuana eradication. But that's neither here, nor there. There are worse steels for big knives than 1095. That said, even though I own several 1095 blades, I actually prefer 5160, or even 6150. Both take, and hold, a more than acceptable edge for my uses. This includes a couple of working tomahawks in 6150, no issues with edge-holding, sharpening, or damage that wasn't caused by stupidity on my part, and was easily remedied. 1075 should be just as tough, and capable, with a good heat treatment, I would think.

Nice to see you on board, D Dan Maragni !
 
I have posted an article on the Ontario website about the history and reasoning behind the change from 1095 to 1075 steel. Go to the website and click on the "Education" heading and then click on the somewhat psychedelic image of myself (I had nothing to do with the image) and the link to the article is there. I would be very interested in any feedback on the article.
 
That was a great write up. Thanks for that. Something else for people who are poo pooing 1075 to remember is that many, many Japanese Samurai swords are made from 1075 as well. Because of its ability to absorb shock loads during strikes.
 
I'm glad you like the article and thank you for your positive response. You are quite correct about the reasoning behind the use of steels with carbon contents of about 0.75% by the Japanese swordsmiths. Although the carbon contents were similar to 1075 it is important to remember that the bloomery steels that the Japanese (and most every other swordsmith throughout the ancient world) were very different from modern steels. Fortunately there are a fair number of blademiths today who are smelting their own steels and providing a great deal of insight about the working and performance of such steels. It is a great time to be a student of the blade arts.
 
Dan Maragni said:
I'm glad you like the article and thank you for your positive response. You are quite correct about the reasoning behind the use of steels with carbon contents of about 0.75% by the Japanese swordsmiths. Although the carbon contents were similar to 1075 it is important to remember that the bloomery steels that the Japanese (and most every other swordsmith throughout the ancient world) were very different from modern steels. Fortunately there are a fair number of blademiths today who are smelting their own steels and providing a great deal of insight about the working and performance of such steels. It is a great time to be a student of the blade arts.
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Dan, I read your article about the switch to 1075 from 1095. Maybe I missed it, but I didn't see anything about 5160. I've only been buying knives over the past 2 years, so I never got a chance to see the 5160 Spec Plus Gen ii knives. I actually didn't know they existed until today. I own both the SP10 and SP6 in 1075. I have a simple question. Do you feel the 5160 Gen ii knives were superior in terms of durability and edge retention, or are the current 1075 versions superior or equivalent? I'm asking because many Spec Plus Gen ii knives are still being sold for reasonable prices. I was thinking of picking one up. But, if my 1075 SP10 and SP6 are just as good, I won't bother. One thing I did notice is that many of the Gen ii knives have finger choils, which are absent from the current Spec Plus line. If you can't answer this question, because you're still working for OKC, I totally understand.
 
I didn't mention 5160 in the article because Ontario had already discontinued using the steel when it was decided to consolidate our steel use.

The 5160 blades are probably the toughest, most durable blades Ontario has produced but it is unlikely you would ever notice the difference in toughness between the 5160 and 1075 blades unless you really pushed them to the limit. This is a limit that is unlikely to be reached in even extreme use and which I have only reached when I am intentionally testing knives to destruction (I have done some terrible things to knives and swords). The 1075 blades would have slightly better edge retention compared to the 5160 blades and are certainly tougher than the previous 1095 blades. As you know every knife is a compromise of design and materials and it is ultimately the user who determines their priorities in their selection. This being said it is important to remember that the primary feature which determines knife performance is blade geometry with steel and heat treatment playing a supportive role.

I always include choils in the knives that I design so there is clearance for sharpening and to prevent the resharpened edge from eroding past the profile of the blade.
 
Dan Maragni said:
I didn't mention 5160 in the article because Ontario had already discontinued using the steel when it was decided to consolidate our steel use.

The 5160 blades are probably the toughest, most durable blades Ontario has produced but it is unlikely you would ever notice the difference in toughness between the 5160 and 1075 blades unless you really pushed them to the limit. This is a limit that is unlikely to be reached in even extreme use and which I have only reached when I am intentionally testing knives to destruction (I have done some terrible things to knives and swords). The 1075 blades would have slightly better edge retention compared to the 5160 blades and are certainly tougher than the previous 1095 blades. As you know every knife is a compromise of design and materials and it is ultimately the user who determines their priorities in their selection. This being said it is important to remember that the primary feature which determines knife performance is blade geometry with steel and heat treatment playing a supportive role.

I always include choils in the knives that I design so there is clearance for sharpening and to prevent the resharpened edge from eroding past the profile of the blade.
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I appreciate the detailed explanation. The SP53 is the only Spec Plus ii still available in 5160. I'll have to think it over. Edge retention is pretty important for knives, so I think I'd prefer better edge retention over extreme toughness. 1075 seems like a nice balance. I suppose if I was buying a sword, 5160 might be a better choice.
 
Another very good choice for swords is 6150 steel. I had the opportunity to study a Norman sword from the 12th century, took extensive measurements and had them reproduced in 6150 steel. I subjected them to very abusive testing including cutting into iron pipe and bar stock and was unable to break them. I was eventually able to cause the blades to take a slight set by cutting into the corner of a square bar. Since the ultimate goal of a sword smith is to make a sword that will not break (hence the traditional use of laminations, differential heat treatment, etc) I was very impressed with this steel.
 
Dan Maragni said:
I was responsible for the change of steel for the RTAK II from 1095 to 5160 at Ontario Knife Company, I had introduced 5160 steel to Ontario when I designed the Spec Plus Gen IIs. I had been forging and testing knives from W-1, W-2 and 1095 for years when I started working on longer blades and decided that I needed a tougher steel to survive the stresses to which a longer blade would be subjected. I consider the primary failure in a blade is breaking and wanted to focus my experimentation on preventing this failure. I made blades and tested them in 1060, 1075, 5160 and 6150 and found that they were all "tougher" than the higher carbon steels and, to my surprise, cut as well or slightly better than the higher carbon steels (tested on manila rope, hard and soft woods and a variety of flexing tests involving a vise and cheater bar). When I arrived at Ontario in 2007 I was presented with some RTAK IIs which had a variety of fractures through the blades and thumbnail fractures along the edges. The RTAK II has a wonderful blade geometry for cutting and slicing and I didn't want to change that so I suggested changing the material to 5160 with the heat treatment I developed in my shop. Some years before I had added a couple of digitally controlled kilns and built an agitated quench tank for my shop and performed and documented a series of physical tests and metallurgical examinations on each steel mentioned above and found the optimum performing microstructures for each steel. When Ontario did change the steel to 5160 the fracturing problems ended and ultimately Ontario decided to consolidate their steel uses and switched to the blade steel to 1075 (also no fracturing problems) so the RTAK IIs are currently made from 1075. I am currently working on an article which will tell the history and reveal the reasoning behind the decisions which will be available on the Ontario Knife Company website fairly soon.
Click to expand...
I am again interested in the RTAK 2 and began googling and stumbled on the thread I started a year ago. thank you for replying. Companies that talk to their customer base always stand out to me. I apologize for only now seeing and responding to your reply. thank you again for responding.
 
DDDYLN said:
I appreciate the detailed explanation. The SP53 is the only Spec Plus ii still available in 5160. I'll have to think it over. Edge retention is pretty important for knives, so I think I'd prefer better edge retention over extreme toughness. 1075 seems like a nice balance. I suppose if I was buying a sword, 5160 might be a better choice.
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Hi Dan, what are thoughts on SK5 which I believe is roughly equivalent to 1080, and
I therefore imagine be pretty close to 1075 if properly heat treated?

I have a cold steel bushman that lost a finger nail sized chip out of the cutting edge, and was wondering if it was just a random QC issue relating to the heat treat. The steel seemed quite granular around the chip.

Thanks for the informative articles!
 
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