Sharpening Jointer Knives

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Forum topic by cmaeda posted 09-12-2008 06:16 AM 17757 views 2 times favorited 17 replies Add to Favorites Watch
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205 posts in 3755 days

09-12-2008 06:16 AM

Topic tags/keywords: jointer jointer knives sharpening

Has anyone ever tried sharpening Jointer knives?
I’ve been using my jointer a lot for the past year and its’ getting to be a hassle (not to mention expensive) to send the knives out to be sharpened.
I sharpen all my own chisels, gouges and planes so I’m thinking about purchasing a few 10” DMT diamond stones and having a go at sharpening the jointer knives myself. Has anyone ever tried this? Any tips or useful jigs? Or is it better to go with a sharpening service?

17 replies so far

View SteveKorz's profile


2139 posts in 3915 days

#1 posted 09-12-2008 06:57 AM

I usually take mine out and sharpen them by hand, running the edge over wet sandpaper thru the grits on marble. I don’t use a guide or anything, I just do it by feel. I’ve never had any complaints about doing it this way. I sharpen my planer blades the same way.

-- As iron sharpens iron, so one man sharpens another. (Proverbs 27:17) †

View marcb's profile


768 posts in 3874 days

#2 posted 09-12-2008 08:56 AM

If you want a guide, Lee Valley sells one specifically for some sizes of jointer blades,43072,43078&ap=1

You can also cobble one together out of a piece of wood, some clips and a screw.

All that said, what steve said. Just scary sharp them, even if your a stone guy (you have one wide enough for a jointer blade?)

View coloradoclimber's profile


548 posts in 4269 days

#3 posted 09-12-2008 04:07 PM

- Measure the bevel angle on your knives,
- cut a bevel on a piece of wood with that same angle,
- lay the top of the knife against the block so that the knife bevel is down,
- put the block and knife on a flat piece of sand paper or a stone,
- slide the knife back and forth.

Works pretty well to restore a sharp edge. It’s not depth referenced side to side so I dont think I’d recommend it for regrinding a bevel or taking out large dings, but for very quickly and easily touching up an edge it is super fast, cheap, and easy.

View cmaeda's profile


205 posts in 3755 days

#4 posted 09-12-2008 09:11 PM

Wow, thanks for the responses. I’ll have to try these techniques out this weekend.

View Joe Lyddon's profile

Joe Lyddon

10323 posts in 4253 days

#5 posted 10-05-2008 03:23 AM

The tricky part is getting them back into the jointer! :) :D

-- Have Fun! Joe Lyddon - Alta Loma, CA USA - Home: ... My Small Gallery:"

View Doug S.'s profile

Doug S.

295 posts in 3909 days

#6 posted 10-05-2008 01:59 PM

I’ve never done this but saw an article or something years ago not real long after buying my PM54. But somebody had a method for doing them while still in the cutter head. I cant recall what they were doing to lock the head position but I think they were adjusting the infeed table so that the knives stuck up pretty far, removed the fence, and put something thin and flat on the table to protect it, then ran a stone back and forth along the knives. Seemed like it might be a decent method and ensure the knife heights didn’t change but like I say, I never tried it.

-- Use the fence Luke

View tenontim's profile


2131 posts in 3945 days

#7 posted 10-05-2008 11:45 PM

Actually the Powermatic owners manual has a method similar to the one DougS. mentioned, except you don’t lock the cutter head, you level the infeed and outfeed tables, then turn the machine on and slide the sharpening stone across the blades. It will sharpen them, but it’s kind of scary doing it. Takes a real light touch or you’ll take the blades down to far. I have a Grizzly plane blade grinder that I use for my jointer and planer blades.

View Doug S.'s profile

Doug S.

295 posts in 3909 days

#8 posted 10-06-2008 12:03 AM

That method in the PM manual looks about as crazy as hand feeding a Great White Shark. Sounds like you’ve done it though. Does it actually do a good job of sharpening?

Wish I could remember more details of the other method or where I saw it.

-- Use the fence Luke

View cmaeda's profile


205 posts in 3755 days

#9 posted 10-06-2008 04:19 AM

Thanks again for the responses. This is what I ended up doing:
I first got a 6 1/8” x 6” piece of walnut. (the blades are 6 1/8” long)
I found the angle of the blade using an angle gauge.
I transfered the angle onto my tablesaw and set for a 1/2” cut.
The kerf of the blade is 1/8” and my blades are 1/8” thick.
I then ripped 3 lines into the walnut.
I put the blades into the 3 lines. (very snug fit)
I turn my sharpening stone upside down and run it across all three blades at once.
It works well. And since I’m doing all three blades at once, I don’t have to count the number of passes I make.

View tenontim's profile


2131 posts in 3945 days

#10 posted 10-06-2008 02:26 PM

Doug, the PM method will put an edge on the blades, but I prefer to take them out and sharpen them on the blade grinder. It will even the blade heights out, if you’re off a hair, but it’s easy to take them too far, then you’ll have to go in and reset them anyway.
Cmaeda, did you get your board edged properly?

View cmaeda's profile


205 posts in 3755 days

#11 posted 10-06-2008 08:28 PM

Yes, I did test out the jointer after sharpening it and it performed really well. There were no dips, grooves or sniping on my test board.
I forgot to add that I did swipe each one 3 times on a 600 grit diamond stone after I took each blade out of the jig.
I also coated the jig with shellac afterwards to help minimize wood movement. I don’t think this will affect the performance of the jig. I just coat all my jigs with shellac if they are made of solid wood and if I think I’ll use it more in the future.

View hasbeen99's profile


183 posts in 3740 days

#12 posted 11-23-2009 08:33 PM

Some great ideas here, guys. I’ve just run into a dull knives situation with my jointer, and going back and forth trying to decide whether to replace or sharpen. I did order a spare set of knives, and I’ve got an email out to my sharpener to see what they’d charge me, but I like cmaeda’s idea and jig. May try that.

-- "The only thing that counts is faith, expressing itself in love." --Galatians 5:6

View Joshua Howe's profile

Joshua Howe

71 posts in 3675 days

#13 posted 06-14-2012 08:44 PM

I know this is an old post but I thought it would be good to give the web address of what I think Doug S was talking about:

-- Wood,clay,metal, and stone are all just materials, until an artist's hand touches them.--TreeFormDesign

View chocked's profile


37 posts in 2238 days

#14 posted 12-06-2012 05:38 PM

Not to change the subject but- can anyone tell me what are some thickness planers with knives one can sharpen.
I sharpen everything else I have so I am looking for a thickness planer three knives I can sharpen. If anyone know of any please let me know.


-- chocked Tn.

View Gator's profile


383 posts in 3877 days

#15 posted 12-06-2012 05:50 PM


Hendrik Varju from “Passion For Wood” has recently had an article published in Fine Woodworking magazine on sharpening jointer knives while still in the machine. Jan/Feb – 2012 issue, as well as an article on their website from 2011 on building a jig to sharpen planer knives while still in the machine.


-- Master designer of precision sawdust and one of a kind slivers.

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