# Flattening plane blade back.



## hiswillus (Jan 24, 2013)

Fellow woodworkers,

I desperately need someones help! Someone with the insight to see what I'm doing wrong.

I can't even begin to try and explain all the methods and variations I've tried to get a flat back on my plane blades, so I won't even begin to cover them all. I've tried different blades, different surfaces, different media always ending with the same result pictured below. I can tip it forward a bit (ruler trick) and get most of the cutting edge, but still miss the corners. What on earth can I be missing. I've sanded and grided for acumulated days trying to get this down (as I know how importaint a sharp blade is) to no avail.

Oh I pray someone has the insite to have a clue what I'm doing wrong here. Any help would put me in a debt of gratitude.

Thanks,

Jeff


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## chrisstef (Mar 3, 2010)

Jeff - have you tried marking the back of the blade with a sharpie to make sure that you are missing those corners. It looks like you have a little hollow on the back of that iron but I cant really tell. Also you only need to flatten a little bit of the iron so id concentrate on that 1" at the edge. Could it be that your pushing down really hard on the center of the iron and causing a bit of flex?

What grit are you using?


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## JustJoe (Oct 26, 2012)

Others may disagree with me, but in my never-humble opinion:
The back right behind the edge needs to be flat so you can form the bevel on the front, and so that you have a flat place to put the chipbreaker and get a good fit so no shavings can jam in between it and the blade. All that other space from about 1/4" from the blade all the way back to the slot is just wasted time if you're trying to flatten it. I use a stone or sandpaper and only work the 1/2" or so at the tip of the blade. Once I've got that first 1/4-1/2" flat, I'm done with it. 
If you can't get the corners flat then the blade might have been abused or over-cambered (my term, I claim copyright) You might have to grind back 1/16 to get to a flat enough area, but that should be a rare occurence.

The ruler trick is good for blades that have pitting on the back - bevel on the front and the slight back bevel means the cutting tip is from clean unpitted metal in the middle. If the back's not pitted, there's no need to back-bevel.


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## Dcase (Jul 7, 2010)

If you start flattening with a lower grit sand paper… say 80 or 120 grit, you should be able to get the back of that iron flat rather quickly. Once it is flat then you work up the grits until it is polished. I think you just need to spend some more time on it and put a little more pressure at the center of the iron.


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## hiswillus (Jan 24, 2013)

Yea, weather you like your whole back flat (OCD) or just the end I can't get either. If the blade was "over-chambered" (all copyrights respected by the owner) wouldn't it be unlikely that I get this problem on multiple blades? I get up to about 240 grit and it is a perfectly scratched surface, but seems no matter how long I grind on 320 and then on to a 1000 grit water stone I loose it somewhere in there. Maybe that's to big of a jump, but I figured most people do it with 3 steps or something don't they. I figured a fine diamond stone direct to the 1000 grit should have done the trick. So dan you can see I've seemed to have gotten it flat all the way up to 320 and still loose it somewhere so I don't know what the deal is.


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## chrisstef (Mar 3, 2010)

Looking a bit closer at your scratch marks are you moving the iron back and forth the long way? If so it could be causing your corners to dig it ever so slightly.


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## hiswillus (Jan 24, 2013)

chrisstef I thought that as well was likely the problem! It seems the larger scratches are on the outside, but this is highly likely the problem as I remember once switching grits and suing 2 fingers to "third" the blade and remember at my first check I actually had two scratch patterns where my fingers where. Couldn't believe that I cold apply that much pressure in that short of a distance and have that problem :/


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## hiswillus (Jan 24, 2013)

chrisstef I usually alternate directions every grit to make sure I have covered the whole surface completely.


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## bondogaposis (Dec 18, 2011)

You need to start w/ a coarser grit and do most of your honing at that grit until it is flat, then and only then start moving up the grits. I begin w/ 220 grit diamond stone. If you are using sandpaper use 220 or even 150 to flatten, they will cut much faster than 320 and give you the results you are looking for w/ much less effort.


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## chrisstef (Mar 3, 2010)

Sharpie the back of the iron closest to the cutting edge on the back and try running it the other way on the sandpaper or stone so that the bevel is 90* to your sharpening surface instead of head on. (I hope im making sense).

Id stick with one direction and using a magic marker on the back to make sure you're getting flat personally. I hope we got ya figured out here brother.


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## hiswillus (Jan 24, 2013)

I began with a 600 grit diamond stone and moved up the grits and seemed to keep the flat until I reached 320, so that shouldn't be the problem bondagaposis…


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## hiswillus (Jan 24, 2013)

In other words push and pull parallel to my sanding media vs. perpendicular pushing and pulling right chrisstef?


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## chrisstef (Mar 3, 2010)

Excuse my rudimentary designs here but lets pretend my notepad is your stone and the chip breaker isn't on your iron .. Follow the arrows.

Hand position also not accurate, I was just keeping it from falling off my desk.


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## hiswillus (Jan 24, 2013)

I'll go give it another go. Thank you all so much for your input as I'm desperate to use my first properly flattned plane blade. I'm sure it's going to make a world of difference. I especially appreciate your persistence in helping chrisstef


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## chrisstef (Mar 3, 2010)

Not a problem brother, im actually quite astonished that I might have actually figured something out.

Keep up posted as to your progress Jeff.


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## hiswillus (Jan 24, 2013)

Ok, clearly moving in the right direction here. I think I was applying entirely to much pressure here. I attempted to keep even steady moderate pressure focussing more on the end. However even when removing pressure in the middle and only applying pressure on each corner I still miss the corners. I think I'm going back it up a few grits and try my luck. I'm going to give it a brake though as there is blood allover my keyboard from my finger tip being sanded off :/


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## chrisstef (Mar 3, 2010)

Yea id fall all the way back to 80 or 120 grit if ya got it then proceed up from there. Luckily you will only have to do this once but it looks like youre moving in the right direction broscious. Sweet sweet shaving will be in your future.


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## Dcase (Jul 7, 2010)

600 grit diamond stone is not coarse enough… It will work but it will take a Loooong time… Starting on a really coarse sandpaper will work much faster.


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## sikrap (Mar 15, 2009)

I also think that you need to start with 80 or even 60 grit to get the back flat. I've "invented" a pretty neat gizmo for flattening. Take a piece of MDF about 3" x 6" and then drill 4 3/8" holes with a forstner bit so that you can insert 4 rare earth magnets (with epoxy). You'll and up with something that you can use like a sanding block. Not only does this stop you from sanding your fingertips, but it ensures that even pressure is applied on the blade. I know it seems like 4 itty bitty 3/8" magnets will hold the blade in place, but it does. If you use larger magnets or more of them you may not be able to get the iron off when you're done.


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## hiswillus (Jan 24, 2013)

Great idea Dave! My fingers thank you. Is this a common problem (skinning the fingers) or am I just "special"? I just get so focused on the blade I don't worry about my fingers as it doesn't feel like much at the time…till later.


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## wormil (Nov 19, 2011)

Start with 60 grit sandpaper and don't stop until it's dead flat. The other grits are only for removing marks left by previous grits. Cheap sandpaper will not cut as well as quality stuff.


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## mandatory66 (Jul 26, 2012)

I flatten the back of my irons on a Worksharp takes a few minutes . I start with 220 ,320,1000,6000. The back will shine like a mirror. I then sharpen the iron and finish the back with the ruler trick on a 8000 water stone.. I just lay the iron down on top of the spinning plate with finger pressure on the back. I was going through the same thing you are and got fed up & bought the Worksharp.


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## sikrap (Mar 15, 2009)

Sanding fingers is why I made the jig. I got tired of cleaning up blood. ) If you buy a Worksharp, get the 3000. It will allow you to do more. While it is fast, its also REAL easy to dub an edge with a Worksharp (DAMHIKT), so be careful.


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## distrbd (Sep 14, 2011)




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## TheWoodenOyster (Feb 6, 2013)

Keep hacking away at it. I remember how long I used to work on sharpening blades down and I still spend a decent amount of time on it. In the last couple of weeks I have taken 6 chisels and a spokeshave from factory grind to razor sharp, so I can definitely commiserate with your bleeding fingertips.

I guess what I have learned is that different blades act way differently and often your finger pressure is doing a lot more than you think it is. I had similar problems with the chisels I just sharpened. The edges and corners took much longer to flatten than the rest of the back. I just tried to stay patient and in the end convinced myself that a few tiny flaws were ok. Often, I think some of us forget that this is just a tool and not a fine woodworking piece itself. we get so wrapped up in the perfectly flat "mirror polish" that we waste days on honing. Don't get me wrong, I love a razor sharp edge as much as the next guy, but achieving one shouldn't keep you up at night. Good Luck.

P.S. - When you get to the end, use a strop. I repeat again for emphasis - use a strop. It will change your life


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## waho6o9 (May 6, 2011)

I see a surgical edge in your future Hiswillus, once achieved, remember

to push the surgical edge away from you at all costs.

You can charge a MDF piece with green honing compound to get

a mirror finish as well, or make a leather strop and do the same.

Excellent video, thanks Distrbd!


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## hiswillus (Jan 24, 2013)

So here is the final compromise I allowed myself to be okay with for now. Thanks again for all the input guys


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## hiswillus (Jan 24, 2013)

Ok so I figures since I have a captive audience that has some interest in this topic I thought I'd prolong this a bit 

Seemingly distorted my new DMT "mini" stones. Because of there small size and inexpensive cost I thought I could pick them up and achier them to a larger board and get away with using them to sharpen my plane blades, and see if I liked them before committing to a larger purchase.

Well used some west system epoxy with a few clams and calls to adhere these small beauties to a piece of OSB since I had purchased the 1 micron paste and figured I'd keep it al together right? Unfortunately I noticed after using the stones for a while that there was a equal hump in the centre of each of them. I popped them off the piece of OSB and cleaned them up as best as I could doing my best not to disfigure the original backing. It appears that the arch is also consistent on the backing piece, but this is hardly a reference point anymore.

My question is does anybody out there have any ideas on how I can force these things back into level. I'm thinking some piece of melamine for reference on the diamond side and some pliable pressure on the back side while being epoxied again. However I'm a little gun shy with using the epoxy again (thinking that did something with the plastic/ceramic backing. Other idea was to clean up the under sides better and trust them as a reference point and just clamp down in the centre with a dab of super glue underneath on a piece of melamine.


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## dominikmatus (Mar 4, 2013)

I think only first 5 milimeters are important flattered. Rest part do not have a big influence to making fiber.


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## stefang (Apr 9, 2009)

Twilight zone stuff. I always find flattening the back of the blade the easiest part of the honing process. I usually start with my 600 grit diamond plate and move up to 1200 grit in one step. I apply even pressure with my fingers. The whole operation takes just a few minutes to reach a near mirror finish.


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