Planer knife sharpening jig.

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Project by SASmith posted 936 days ago 11264 views 76 times favorited 46 comments Add to Favorites Watch
Planer knife sharpening jig.
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I like to think of this jig as Tim Taylor’s(from the tv show Home Improvement) take on the Scary Sharp Method.

I made my jig out of plywood to help prevent warp.

Glue and clamp together.

Make two 45 degree rip cuts with an 1/8” thick blade, rotating the jig 180 degrees after the first cut.

Move the fence over enough to roughly center the third kerf.

Cross cut to a length 1/16”-1/8” less than the length of the planer knives. 14 7/8” in this case.

Insert the knives into the slots. Set the jig on a flat surface and while applying downward pressure screw the end caps on.

The rusty knives in the jig before starting to sharpen.

I decided I wanted the knives held more securely and added an F-clamp to apply additional pressure to the end caps.

Here you can see that having a thick jig will help to keep the jig stable while pushing the jig across the sander.
I started with a 40 grit belt and sanded until I exposed fresh metal free of nicks.

Then I coated the knives in magic marker ink and changed to an 80 grit belt and sanded until all the 40 grit scratches were removed. Then ink & 120 grit, ink & 220 grit, ink & 320 grit. This is where I stopped since they were razor sharp and would shave arm hair.

The last step is to remove the bur on the back side of the knives. I did this by dragging the knife across the 320 grit belt(sander NOT running).

The wad of steel wool looking stuff is the amount of metal shavings removed during sharpening.

This jig could also be used by hand if you don’t have a Ridgid OSS (or used as an excuse to buy a new tool)
You would need a piece of granite, glass, or your tablesaw top with PSA sandpaper applied and lots of elbow grease.

This jig is a combination (and improvement imo) of LJ Garry’s jig: and the Deulen jig Thanks to both of them for the inspiration.

Thanks for looking.

-- Scott Smith, Southern Illinois

46 comments so far

View PurpLev's profile


8476 posts in 2244 days

#1 posted 936 days ago


-- ㊍ When in doubt - There is no doubt - Go the safer route.

View Brandon's profile


4136 posts in 1547 days

#2 posted 936 days ago

Excellent. Now can I send my planer knives to you to sharpen them? :-)

-- "hold fast to that which is good"

View Bertha's profile


12951 posts in 1289 days

#3 posted 936 days ago

It doubles as a steel wool maker! I just bought jointer knives too. Drats;)

-- My dad and I built a 65 chev pick up.I killed trannys in that thing for some reason-Hog

View lanwater's profile


3072 posts in 1530 days

#4 posted 936 days ago

This is a great idea.

How do we avoid contact with the sander that is not uniform. Like more pressure here and there?


-- Abbas, Castro Valley, CA

View MasterSergeant's profile


1278 posts in 1284 days

#5 posted 936 days ago

You had me captivated!

-- Kelly, woodworker under construction

View Sodabowski's profile


2001 posts in 1429 days

#6 posted 936 days ago

Incredible how much metal you can take out of these for sharpening!

-- Holy scrap Barkman!

View Dusty56's profile


11638 posts in 2284 days

#7 posted 936 days ago

Are they all still parallel ?
I had to laugh at the Tool Time flashbacks…thank you : )

-- I'm absolutely positive that I couldn't be more uncertain!

View SASmith               's profile


1544 posts in 1583 days

#8 posted 936 days ago

I have sharpened several sets of planer knives using this method.
To make sure they are uniform black the cutting edges out with ink again and use the traditional scary sharp method with PSA sandpaper on a flat surface. The ink should be removed evenly with just a few strokes.
I have never had a problem with unevenness though it never hurts to check.

-- Scott Smith, Southern Illinois

View SASmith               's profile


1544 posts in 1583 days

#9 posted 936 days ago

@ Sodabowski:
It looks like alot of material removed but it is very fluffy.
I only removed enough to get the nicks out.
I used to measure the amount of material removed and it would range from 10-20 thou, less if they are nick-free.
I know that a “professional sharpening” will remove far more material.

-- Scott Smith, Southern Illinois

View jeth's profile


210 posts in 1434 days

#10 posted 936 days ago

Excellent jig, thanks for sharing..

View SPalm's profile (online now)


4740 posts in 2478 days

#11 posted 936 days ago

Now that is down right clever. Looks like it works great.
I did not know they made all those grits in belts. I need to look around some more.
So much to do, so little time.


-- -- I'm no rocket surgeon

View boxcarmarty's profile


8966 posts in 956 days

#12 posted 936 days ago

Just in time, I noticed this afternoon that my planer needed some attention. Looks like I have a maintenance project for tomorrow…..

-- My mind is like lighting, one brilliant flash, then its gone.....

View NormG's profile


3980 posts in 1600 days

#13 posted 936 days ago

Great idea, thanks for sharing. Its amazing how much metal is removed

-- Norman

View boldham's profile


2 posts in 936 days

#14 posted 936 days ago

Really impressive jig. I’ll give this a go over the weekend! I’m always amazed at the ingenuity of DIYers! Thanks!

View glue4you's profile


160 posts in 1076 days

#15 posted 936 days ago

I like the jig for its creative approach towards sharpening planer knives but I share the concern that knives might become uneven (talking about the thou category). I found that – talking for myself – I cannot keep an edge straight unless I use something straight to prevent me from diving into the material.

Last night when I was browsing through Steve’s links (LJname: stevinmarin) I found this jig that pretty much solves the same problem but without the OSS (which is kind of bad if you really need an excuse to buy this tool):
Video can be found here

Thanks for sharing!

-- Alex ----- Bavaria in Germany

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