Laser or Water?

[Taz]

You need to leave the edge thicker to quench so it doesnt crack or warp on you. You should not quench a fully ground and sharpened blade!!

Aebl is very warpy , so you may want to harden before grinding, but that makes grinding harder and the steel will need to be kept cool so it doesnt overheat and lost the temper. It may still warp doing a chisel grind on it too?

There are multiple ways to do things. I am not sure why you are so focused on "best way" and "definitive answer" when there are multiple good ways to do things, all with their own pros and cons.

Most custom knife makers harden the blades then grind, or partially grind, harden and finish grinding. If they forge, they may forge profile and bevels partially and then HT and grind, or grind, HT and then finish grinding. It dependsnon a capability, processes and equipment available to whomever is making these.

If it were me, I would get the profile water jet cut out, rough mill the bevels leaving .030" thick at the edge, heat treat, then finish grinding manually with a belt sander to clean up the profile and surface as well as the blade grind. Doing a hook blade can be difficult with a belt sander though if its a sharp/tight radius. Hawkbill isnt bad, but a J hook would be very hard.

 

[Killean]

You need to leave the edge thicker to quench so it doesnt crack or warp on you. You should not quench a fully ground and sharpened blade!!

Aebl is very warpy , so you may want to harden before grinding, but that makes grinding harder and the steel will need to be kept cool so it doesnt overheat and lost the temper. It may still warp doing a chisel grind on it too?

There are multiple ways to do things. I am not sure why you are so focused on "best way" and "definitive answer" when there are multiple good ways to do things, all with their own pros and cons.

Most custom knife makers harden the blades then grind, or partially grind, harden and finish grinding. If they forge, they may forge profile and bevels partially and then HT and grind, or grind, HT and then finish grinding. It dependsnon a capability, processes and equipment available to whomever is making these.

If it were me, I would get the profile water jet cut out, rough mill the bevels leaving .030" thick at the edge, heat treat, then finish grinding manually with a belt sander to clean up the profile and surface as well as the blade grind. Doing a hook blade can be difficult with a belt sander though if its a sharp/tight radius. Hawkbill isnt bad, but a J hook would be very hard.

Taz - thank you for your thoughts.

I am sure that there many ways to skin a cat, as my Father used to say. The reason that we need a definitive and fixed production method is that they must all be indentical and they will be made in runs of at least 2000, yes 2000, at a time. Each process will be done by different specialist; we are not using a knife making company - because we cannot find one in the UK who can do the job! We are not making making one off masterpieces or the odd 100s for various SF teams around the world. Like this fellow does - https://www.facebook.com/search/top?q=stuart mitchell knives His advice was useful but not for big production runs and hooked blades - he edged one for me beautifully but he said it took him nearly an hour.

You mention AEB-L and that is one of two options - the other being SF100; which makes the Made in England story complete.

Did you see the photos' link to WeTransfer?

 

[Killean]

Taz - thank you for your thoughts.

The reason we need one solution is because they will be made in runs of at least 2000 a time. We are not making one off masterpieces or the odd 100 for SF teams.
AEB-L is one of two options, the other being SF100 which completes the Made in England story.

Did you see the photos on the Wetransfer link? https://we.tl/t-ghgLhGIfmB

 

[Taz]

This is what he is trying to make:

Profile is easy. Waterjet is better for companies clean up wise and not dealing with the HAZ. That is the definitive answer. If the manufacturer is telling you that, you need to listen to them.

The curved grind is the hard part. Taking a custom maker an hour to do that grind shows the complexity. I can grind a 3" knife in hardened AEB-L, full flat grind, 1/8" stock to 400 grit belt and then scotchbrite finish in 20 minutes. Production will be able to look at that and figure out how to best CNC the shape and may want to simplify things, too.

You need to find a company that can make these and listen to their input. They know their machines and equipment and what they can/cannot do and how things are done. Asking custom knife makers how we would make this is completely different than how a manufacturer would approach this. As was said multiple times before, the HAZ from laser cutting is a PITA to deal with in a manufacturing mindset and needs extra steps to deal with where waterjet cutting does not bring those issues to the table at all. Waterjet, heat treat, machine bevel. Even for custom knife makers, making 2000 at a time, even spending a minute or 2 dealing with the HAZ adds LOTS of time to batches. 2 minutes, 2000 units, adds 66 hours to production time.

Seeing this design, I would simplify the grinding and put the blade onto a small wheel at an angle and grind just the inner curve that hits the small wheel, not the straights. If it's for seat belts/zip ties/flex cuffs, the longer flat portion will not cut anything anyway typically, so you just need the inside curve itself sharpened. Look at gut hooks for deer skinning, you are doing the same thing basically. The inner curve of the edge is sharpened, not all the way up and down typically.

Or make something that uses disposable razor blades that screw into the handle holder. Look at the Gerber Emergency Rescue Hook and the Gerber Vital Zip to get an idea of what I am talking about.

 

[J. Hoffman]

Taz - thank you for your thoughts.

The reason we need one solution is because they will be made in runs of at least 2000 a time. We are not making one off masterpieces or the odd 100 for SF teams.
AEB-L is one of two options, the other being SF100 which completes the Made in England story.

Did you see the photos on the Wetransfer link? https://we.tl/t-ghgLhGIfmB

You state this is a seatbelt cutter? Have you done much testing with the design? I've cut my share of seatbelts. We also have knives similar to that design, but they are intended for another use, and unfortunately they are less than effective. I'm not bashing your product, but I want you to make sure it works in real world applications.

 

[bladegrinder]

I think you might do better with something that accepts a fixed or replaceable razor blade in a smaller hook area. we all know what a seat belt cutter looks like, but that doesn't look like it would be good at cutting seat belts.
I've seen mangled body's in smashed cars and what's shown there looks unwieldy and might end up cutting something else while trying to hook a seat belt.

 

[Killean]

I think you might do better with something that accepts a fixed or replaceable razor blade in a smaller hook area. we all know what a seat belt cutter looks like, but that doesn't look like it would be good at cutting seat belts.
I've seen mangled body's in smashed cars and what's shown there looks unwieldy and might end up cutting something else while trying to hook a seat belt.

"Seatbelt cutter" is a euphemism. We have supplied "emergency services rescue cutters/knives" for 27 years.
We also sell these -LINK REMOVED but for every one we sell, we sell one thousand others.~
It all started in 1997 with these - LINK REMOVED which we bought in from the Hamburger Woollen Company of New York - we now have them made for us in Taiwan and buy a LOT. However we don't want to use the Far East as I said way back in this thread; that is why I have designed exactly what our main customers want and we have orders from the "early adopters".
Forgive me for not going into more detail, but I don't want "Chinese Copies" appearing around the world.

 

[J. Hoffman]

The LC1 is the exact knife we have. Real world, they don't work as intended, and someone with a real knife is usually called in to make the cut. I understand why they are sold, but they just don't work as intended.

 

[Killean]

The LC1 is the exact knife we have. Real world, they don't work as intended, and someone with a real knife is usually called in to make the cut. I understand why they are sold, but they just don't work as intended.

Indeed so, unless super sharp they can let you down. We sharpen/maintain about 7,500 every year.
These are better - but rather too savage for some of our customers: LINK REMOVED

Nice website, great knives Jess!

 

[Stacy E. Apelt - Bladesmith]

Since this has turned into a sales thread and now links to products are being posted, I am locking the thread.
Killian does not have the membership level to discuss sales and link products.

To be honest, I don't know why his company is asking us questions that they should already know since they sell many cutting products.

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