Author Topic: Getting a uniform edge on curved knives  (Read 375 times)

Offline Adrian Lopez

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Getting a uniform edge on curved knives
« on: November 19, 2019, 06:09:40 am »
According to the Tormek manual the width of the bevel you get at the tip of a knife will depend on whether the knife jig is mounted close to the handle or close to the tip. Getting a bevel of uniform width therefore requires placing the knife on the jig at the right position.

I use black permanent marker to get an idea of where grinding will occur but I find this works better for the long, straight section of the knife edge than it does for the curved tip. It's hard for me to figure out what's going on at the tip unless I turn on the machine and do some grinding when for the straight section I can just turn the wheel by hand and see where any grinding will occur.

Are there any tips to getting a consistent bevel width other than using permanent marker like this?

Offline cbwx34

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Re: Getting a uniform edge on curved knives
« Reply #1 on: November 20, 2019, 01:57:18 pm »
According to the Tormek manual the width of the bevel you get at the tip of a knife will depend on whether the knife jig is mounted close to the handle or close to the tip. Getting a bevel of uniform width therefore requires placing the knife on the jig at the right position.

I use black permanent marker to get an idea of where grinding will occur but I find this works better for the long, straight section of the knife edge than it does for the curved tip. It's hard for me to figure out what's going on at the tip unless I turn on the machine and do some grinding when for the straight section I can just turn the wheel by hand and see where any grinding will occur.

Are there any tips to getting a consistent bevel width other than using permanent marker like this?

I think you're on the right track... what I do is mark the blade with a Sharpie (permanent marker), setup the machine at whatever angle I want to sharpen at, then turn the machine on, and make a very light pass or two... this will tell me where the marker is being removed, without taking off any significant metal.  (Good lighting helps, and maybe a small magnifier if needed, at least while learning).

"Where to clamp" depends on the shape, thickness, etc., and how you maneuver them (some you can just lift the handle, some rotate and lift, etc.).   After some practice, you'll get a pretty good idea of about where it should be clamped.  What you might want to do is take a couple of practice blades with different shapes, mark them with a Sharpie, then try clamping them in various positions, and see where the marker comes off in the various positions, so you get a basic feel of where it should be.

Another thread that may give you some ideas...Jan made a template for setting the knife in the clamp, again it depends on how you maneuver the knife (lifting vs. pivoting)... you can read it here...  https://www.tormek.com/forum/index.php?topic=2654.0

Offline Even

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Re: Getting a uniform edge on curved knives
« Reply #2 on: November 20, 2019, 02:17:09 pm »
Hello.
What I think gives a most even grinding along the entire blade is by using a "Pin Pivot Collar"
If you do a search here you will find more information about this, and wootz has also made video about this.

Even

Offline cbwx34

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Re: Getting a uniform edge on curved knives
« Reply #3 on: November 20, 2019, 02:29:38 pm »
Hello.
What I think gives a most even grinding along the entire blade is by using a "Pin Pivot Collar"
If you do a search here you will find more information about this, and wootz has also made video about this.

Even

Good point.

Here's a video showing both setups that might help...

https://youtu.be/6q5Tj48kDh4

Offline Adrian Lopez

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Re: Getting a uniform edge on curved knives
« Reply #4 on: November 24, 2019, 03:16:37 am »
Thank you all for your replies. I have found another post that looks like it might help, though I haven't tried yet:

The one change you should make to the Tormek

To the degree that the angle and shape of the bevel depend on the precise line of contact with the grinding wheel, drawing a line across the width of the wheel may provide a useful reference for positioning the knife in the jig such that the knife remains in contact with this line as one approaches the curve.
« Last Edit: November 24, 2019, 07:06:10 am by Adrian Lopez »

Offline Adrian Lopez

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Re: Getting a uniform edge on curved knives
« Reply #5 on: November 24, 2019, 07:02:10 am »
I tried the line trick described in cbwx34's "The one change you should make to the Tormek" thread and I think it worked pretty well. The bevel is a little wonky in places because of previous attempts at sharpening (this is my throwaway knife), but I like the way it came out overall.

« Last Edit: November 24, 2019, 03:59:36 pm by Adrian Lopez »