What do you use to Sharpen when the tool is very out of Flat?

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    I recently bought a #5 plane off ebay, and it looks like the guy before me who was sharpening it took it to an angle grinder with little to no regard for what the word ‘flat’ meant. I’ve been trying to get the back of the iron back to flat on an Eze-Lap Coarse Diamond stone, but it’s taking forever to get down through all the dips and gouges made by the previous owner.

    What do you all use for the really rough honing when the diamond stones are taking too long? Should I go get some 150 grit sandpaper and use my granite slab, or is there a better way? I’ve heard the sandpaper can leave grooves in the iron if it’s too rough of a grit, so I’d like some input before I move towards that path.

    Thanks in advance for your valuable knowledge!

    -Tim Anderson, UT, USA


    If it is that bad, I start with 80grit on plate glass to get all the dips out. Pay some attention to keeping the bottom square with the sides. Then switch to 150grit. Then you should be able to switch back to the diamond plates.

    Every time I start a new grit, I coat the bottom of the tool with black magic marker so I can see my progress.

    You will want to vacuum off the sandpaper every once in a while also.

    Have fun…

    Located in Honeoye Falls NY USA. The Finger Lakes region of Western NY.

    "If you give me 6 hours to fell a tree, I will take the first 4 to sharpen my axe" Abe Lincoln

    david o’sullivan

    i would do the same as Brett and move up through different grits

    "we can learn what to do, by doing" Aristotle


    I also agree with Brett. I start with 180/220 wet-or-dry to see what the wear pattern looks like and if it is concave or convex. If it’s pretty bad I go to 80 grit. I recommend this paper here; it’s pretty cheap and it is silfa fa-carbide which cuts metal a bit faster than aluminum oxide. It is NOT wet-or-dry, so no water:


    As strange as it sounds, I’ve actually had better results with this stuff when I DON’T brush away the swarf. The paper cuts longer when I leave it there. From this I go to 220 then 600 then Simichrome metal polish. I went to 2500 grit the first time but then I figured what’s the point since a 1200 grit diamond plate doesn’t leave that fine a surface on the bevel anyway. I settled on 600 grit paper for the back.

    One thing I won’t do again is try to flatten a convex back. I did that on my first plane and it took FOREVER to flatten, and I still only got like the first 1mm flat all the way across. If I ever have to do that again I’m gonna do like that one dude said in his book, about taking a Dremel and grinding a slight concavity in the middle area, then flattening on paper.


    Thanks for the advice everyone. I’ll pick up some higher grit sandpaper today and work my way down, and then post some before/after photos when I get it all done.


    -Tim Anderson, UT, USA

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