Cutting out the knife profile

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Saltlife027

Joined
Jan 11, 2019
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hello im am just beginning to make my own custom knives and I am having problems with the steel warping some when i cut out the profile. I am using an angle grinder at the moment and when i am done cutting the blank comes out somewhat warped. Im not sure if its from getting to hot in certain points and cooling which is causing the warp or something else. If anyone has any suggestions on how to prevent this problem any help would be great. Thanks
 
It is probably internal stresses in the steel. I doubt angle grinder heat could ever significantly warp steel. Have you ever taken a straight 2x10 and ripped it half and got 2 boards with a bow in them? Same kind of thing.
 
I have always used a bandsaw. Alot of guys use the harbor freight one with great success. I think they can be had for around 100 dollars. As far as the angle grinder, heat is likely your issue. Try cooling with water. Also thicker stock will be less prone to warpage. If you are even remotely serious about knifemaking a bandsaw is a must in my opinion. Good luck.
 
Yeah Im looking into getting one. And yeah im guessing its from uneven heating of the steel. You think the small 9” band saw from Harbor freight can cut steel? I dont have the money to buy a proper steel cutting one at the moment. This hobby has already cost me a lot lol.
 
Check out ekim knives on youtube. He uses that porta band and goes into detail about costs and setup. While your there watch his series on fixed blades. I think you will find his content very helpful.
 
Straightening and flattening is just a part of life when it comes to knifemaking, might as well get used to it from the start... ;)
 
Stang Bladeworks said:
Check out ekim knives on youtube. He uses that porta band and goes into detail about costs and setup. While your there watch his series on fixed blades. I think you will find his content very helpful.
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Mike offers a lot of great info on his videos. Definitely a great watch. As far as portaband saws go. They are awesome!!! A portaband and a Swag table and your set
 
Saltlife027 said:
Yeah Im looking into getting one. And yeah im guessing its from uneven heating of the steel. You think the small 9” band saw from Harbor freight can cut steel? I dont have the money to buy a proper steel cutting one at the moment. This hobby has already cost me a lot lol.
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I still use a hacksaw since I don't have a lot of extra space. In the end cutting profiles is a very small fraction of the time I spend on a project. I can actually cut very quickly with a hacksaw and fairly accurately as well.
 
No matter how you cut out the profiles, once the shape is cleaned up, you need to check for warp and twist. Correct it before starting the bevels.
Check after grinding and before HT.
Check again after HT.

This is all part of knifemaking, and everyone has to deal with it.
 
tell us more details, what type of steel is it, how thick is it ? does the metal turn blue or brown as you use the angle grinder? my warps usually come after heat treat, and i fix them by counterbending during the temper cycles.
 
What type of disk are you using on the angle grinder? I use the .045" cutting disks sometimes and they sure work good. Some along these lines: https://www.amazon.com/dp/B005B8LZCI/ Before I got those I'd always used the 1/4" thick grinding disks and never thought about cutting out with an angle grinder. These actually work pretty good. I normally use a vertical portaband with homemade table.
 
Yeah i use .045 cutting disks from sait. They cut alright but they can heat up the steel real quick. I gotta look in to getting a bandsaw eventually
 
I can confirm that even if you cut with the band saw, you have distortions, probably due to stress inside the steel. I faced this problem at the beginning of my knives making, I bought steel strips already curved ... so first I straightened the strip band, then cut the knife shape and straightened, then grind the blade, then I tempered and checked for possible distortions .... it's a process to learn is part of the game!
 
Get a portaband. Or get buff and use a hack saw. Will cut down on your warpage due to lower heat. Also buy steel from respected suppliers. Ive had a lot of issues with ebay and craigslist steel in the past
 
Kali4nia said:
Get a portaband. Or get buff and use a hack saw. Will cut down on your warpage due to lower heat. Also buy steel from respected suppliers. Ive had a lot of issues with ebay and craigslist steel in the past
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I agree. Most of my recent work has started with precision ground CPM 3V. Although I have access to a bandsaw at work, I have never bothered to use it since I'm very quick with a hacksaw. I can usually make 30" of cuts in 20 minutes or so. (of course I'm only making 1-4 pieces at a time). I've never had a detectable warp from cutting the profiles this way. The only time I was tempted to use the bandsaw was recently cutting a pommel from a mild steel block with a 3"x1.5" cross section...that was a bit of a workout.
 
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