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knife won't sharpen

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Forum topic by Karda posted 12-25-2017 04:04 AM 845 views 0 times favorited 10 replies Add to Favorites Watch
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Karda

1303 posts in 728 days


12-25-2017 04:04 AM

have you ever had a knife not take a carving edge. i have a small knife I have been working on. I want a longer bevel. I got it where I want it and very sharp with coarse stones but when i got to high grits it seemed to get duller. that happens sometimes but change the angle and im good but this knife just won’t sharpen. Is there any cure other than geting another knife thanks Mike


10 replies so far

View Dave Polaschek's profile

Dave Polaschek

2703 posts in 756 days


#1 posted 12-25-2017 12:20 PM

The only time I’ve had severe problems with getting an edge is with composite blades where there’s a hard layer sandwiched by softer metal. If you’re sharpening asymmetrically (or the blade was made asymmetrically) so that the harder layer isn’t centered on the edge, you’ll have a tough time getting it to stay sharp, as the softer edge will roll over far too easily.

Otherwise the turn a wire edge (or burr), then knock it off method of sharpening should get you to a sharp edge eventually. But if you’ve greatly changed the blade profile, you may have a lot of work to get the burr at each step.

The other problem is if you’re not using a guide (or using one incorrectly) so that you’re not always sharpening at the same angle. If you’re changing angles when you don’t mean to, it’s very hard to get to a sharp edge and then stay there as you move up through the grits.

-- Dave - Minneapolis

View KenKorch's profile

KenKorch

10 posts in 342 days


#2 posted 12-25-2017 04:22 PM

Karda,

I’m certainly not an expert on sharpening blades, but I’ve had tremendous success using a Spyderco Tri-Angle Sharpmaker to sharpen knives. It is easy to use and and it is highly regarded on knife forums. I believe that today it even comes with a DVD that shows you how to use it.

The trick in my mind is to maintain a consistent angle – whatever it is – as you sharpen the blade. Also, I’ve always assumed that the fact that the Sharpmaker moves into the ceramic rods prevents the buildup of that wire edge.

https://www.spyderco.com/catalog/details/204MF/77

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Karda

1303 posts in 728 days


#3 posted 12-25-2017 04:38 PM

ok thanks

View Carloz's profile

Carloz

1147 posts in 765 days


#4 posted 12-25-2017 05:18 PM

I bet it is stainless.

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Karda

1303 posts in 728 days


#5 posted 12-25-2017 05:41 PM

that is possible is there a way to tell, the blade is not marked in any way

View LesB's profile

LesB

1838 posts in 3617 days


#6 posted 12-25-2017 07:06 PM

Good quality stainless is non magnetic but should take a good edge.
Lengthening the bevel leaves the edge highly prone to curling so careful strokes on each side our using a butchers steel to straighten the edge can help. I prefer to use a diamond coated sharpening rod which straightens the edge and also removes a small bir of metal..so it re-sharpens the edge between regular sharpening. I particularly link this for kitchen knives.

I have found that “cheap” blades are hard to put a good edge on and loose their edge quickly. Also laminated blades like Buck knives can be difficult to sharpen (the center layer is very hard) but hold their edge for a long time.
If the knife is important to you, you could thry re-tempering is and then see if it will take an edge.
Otherwise trash it or turn it into a screw driver…lol

-- Les B, Oregon

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Karda

1303 posts in 728 days


#7 posted 12-25-2017 07:12 PM

not important, picked it up on ebay when I first started carving, looks line I have a new bench knife thanks for your help

View Loren's profile

Loren

10477 posts in 3822 days


#8 posted 12-25-2017 07:31 PM

I’ve sharpened knives on stones. It can be
a little tricky. It’s easy to round the bevel
a little and then when fine honing you may not
be working the actual edge, even though the
bevel appears to be getting polished.

These days I use inexpensive ceramic hones
on knives. I have one called a SharpNEasy
I bought at Woodcraft that was cheap it works
well.

View AESamuel's profile

AESamuel

87 posts in 1397 days


#9 posted 12-26-2017 08:03 PM

Unless they messed up the heat treatment with the knife then it will most likely be a technique issue, I doubt it’s to do with the bevel being too fine as it’s easier to get a sharp edge on one. Bear in mind a long bevel will take longer to sharpen especially on higher grits due to having to remove more metal.

Make sure whatever angle you use is consistent, of you are absolutely certain it is then make sure your stones are flat. A slightly curved stone will knock the edge off quickly with a fine bevel. You mentioned using different angles, unless you’re specifically going for a micro bevel or secondary bevel then pick a bevel and stick with it, otherwise you’ll be sharpening different parts of the bevel all the time.

Fine stones generally cut slower so will take longer, don’t progress through grits too quickly, make sure your burr is very detectable on one side, then the other, before you move up a grit.

Last thing I can think of is when stopping, don’t do the stereotypical “flick” at the end of the stroke. Make sure your angle is consistent, just as on the stones. Don’t use too much pressure either or you will round off the edge, especially on a thin bevel.

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Karda

1303 posts in 728 days


#10 posted 12-27-2017 04:24 AM

thanks for the advice, I am back to my diamond cards I like them better than stones. Here is a pic of the blade, it not to good but u get the idea. I have a couple moras and realy like the long scandi grind. Is this blade to small for tha type of grind. its an inch or so long thanks

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