Jointer knife sharpening

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Bruce
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Jointer knife sharpening

Post by Bruce »

I know that the sharpening guide had been discussed before in another thread, but this is not a question about the guide itself, but about the procedure. The guide works just fine for me. Any problems I've had were my fault. Question: in the honing procedure in the manual it says to remove the burr from the back of the knife with a fine stone after honing. The procedure with the guide does not mention removing the burr after sharpening, but I assume that we should. I used an Norton 8000 grit water stone to remove the burr and noticed that the corners of the knife are "high", ie the corners were burnished by the stone, but not the middle of the knife. I know a hand chisel blade should be honed flat across the entire width of the chisel. Wouldn't it make sense to do the same thing with a jointer knife or is that going too far?
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alancooke
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Post by alancooke »

batg4 wrote:I know that the sharpening guide had been discussed before in another thread, but this is not a question about the guide itself, but about the procedure. The guide works just fine for me. Any problems I've had were my fault. Question: in the honing procedure in the manual it says to remove the burr from the back of the knife with a fine stone after honing. The procedure with the guide does not mention removing the burr after sharpening, but I assume that we should. I used an Norton 8000 grit water stone to remove the burr and noticed that the corners of the knife are "high", ie the corners were burnished by the stone, but not the middle of the knife. I know a hand chisel blade should be honed flat across the entire width of the chisel. Wouldn't it make sense to do the same thing with a jointer knife or is that going too far?
batg4, these are good questions that I'm sure will be useful to forum members! Admittedly, I don't have much experience with sharpening the SS jointer blades, but I do with plane blades, chisels, etc., so I'll throw my two cents worth in and see if others agree.

First, as far as honing goes, I think you'll find people on opposite sides until the rapture happens!;) Personally, on tools like jointer blades and turning gouges, I don't think it's needed b/c the burr will be removed as soon as the tool meets the wood. That said, I still hone:) (I just like to feel the perfect edge! After all, I do this for the enjoyment.)

Second, if I understand what you stated correctly, it sounds like the back of your jointer blades are not flat. Whenever I sharpen any tool with a single bevel (ie plane blade, chisel, etc.) I always start by grinding/honing the back of the blade to make sure it's flat. Otherwise, you'll never get a 'truly sharp' edge. I'm assuming this should be the case with SS jointer blades as well. Hopefully someone 'in the know' will chime in soon.
Alan

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Nick
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Post by Nick »

Batguy, have you lapped your water stone? The binder in water stones is very soft, consequently they don't stay flat. For this reason, they are a poor choice for flattening the backs of chisels and knives unless you lap them first. The fact that your stone is abrading the ears of the knives but not the middle seems to indicate that your stone is dished. This is a common problem with all stones; people tend to dwell in the middle of stones when sharpening. The softer stones become dished quickly; the harder stones remain flat longer but they too will dish in time. You have to lap or "dress" them to restore flatness. From my book, "Sharpening:"

"Dress water stones with ordinary wet/dry sandpaper or snading screen. Stick the sandpaper to 1/4-inch-thick plate glass with spray adhesive to hold it perfectly flat. Then rub the stone back and forth over the sandpaper. Use a generous amount of water to float away the waste...Start with a grit that's coarser than the stone and finish with a grit that's similar."

Another suggestion. Make sure your using the conical disk to sharpen your knives. You'll get a much better edge than you will with a flat disk.

With all good wishes,
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Bruce
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Post by Bruce »

Nick,
I prefer Batdude over Batguy. :) Yes, I have a silicone carbide flattening stone that I flatten my water stones with, but it turns out the flattening stone itself needs to be flattened in the manner you described. I assumed that it was flat when I bought it new, and maybe it was, but it hasn't had a lot of use so I was surprised that it was not flat when I checked it.

Also, I do use the conical disk with the sharpening guide.
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Post by charlese »

Hey there batg4 "Batdude"!
You said you have seen the previous posts re: the sharpening guide, but did you carefully check those "spring" washers? They can get in the way if not careful! I replaced mine with smaller washers and they work fine!
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Chuck in Lancaster, CA
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Bruce
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Post by Bruce »

charlese wrote:Hey there batg4 "Batdude"!
You said you have seen the previous posts re: the sharpening guide, but did you carefully check those "spring" washers? They can get in the way if not careful! I replaced mine with smaller washers and they work fine!
Yes, I checked mine and do not see how they could be a problem. Any chance my guide is of a different design then yours?
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Post by charlese »

They are probably the same design and model. Mine came with 3 spring washers that were a bit oversize. When I put in three jointer knives, I found the edge of a couple of washers protruded into the slot where the knife is supposed to fit snugly against the inside of the guide. The result was that the blade protruded a small amount too far out. I replaced the washers with 7 or 8 millimeter washers (can't remember the size right now) and the problem was no more.

Check by sighting down the slot (side view) of the guide when slowly inserting the planer blade. It is hard to get the original large washers to end up on top of the blade, not impossible, but difficult.
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james.miller
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Post by james.miller »

Have you tried turning the washers over? They may be able to catch if they are upside down, it would make the edge hang down.
Jim in Tucson
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dusty
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Re: Jointer knife sharpening

Post by dusty »

marlay wrote: Thu Dec 01, 2022 8:41 am Hi,
I have a jointer knife, it has rusted after washing it, now I want to sharpen it, how can I do it? I also want to buy a new jointer knife, where can I get good ones, can anyone tell me? I also do cutlery .I like this forum and topic very much .
Thank you.
I doubt that we will be of much help. Are there many Shopsmiths in Jakarta where this poster is from?
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Hobbyman2
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Re: Jointer knife sharpening

Post by Hobbyman2 »

If you could get your hands on a new blade just duplicate it , if that is not possible with your equipment maybe you can find something that has the properties needed . as far as in Jakarta ? if it happens not to be spam ? ebay ?? I believe they ship some products world wide and have the avenues of currency exchange . I bought a block plane from a guy in England once .
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