Flattening plane irons

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Forum topic by groland posted 02-26-2011 10:13 AM 2705 views 0 times favorited 11 replies Add to Favorites Watch
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183 posts in 3435 days

02-26-2011 10:13 AM

I have been having a very good time lately fiddling with hand planes. I bought David Charlesworth’s DVDs from Lie Nielsen, and he’s wonderful to watch. I recently bought a 4 1/2 from LN, and it’s a delight to work with. On to my question.

I bought a couple of old hand planes from e-bay: a Stanley Record #5 and a Stanley Bedrock #4 that I would like to use. I believe both of these planes have irons that are not flat on the bottom. When I try to flatten the bottoms on a 1000 grit waterstone, I get a grinding pattern that is an oval shape well back from the bevel and sides of the blade. This would indicate to me, if I understand the graining pattern correctly, that the blade is curved across its width instead of flat, and I am wondering how to correct this.

It may be that trying to remove this curve by hand grinding with water stones simply is going to be far too much labor, but I wonder what, besides ordering an expensive replacement blade, my options are? Can the blade be bent back to a flat position or perhaps ground by a machine shop to a suitably flat surface? Will the latter overly thin the blade?

I am not sure what my options are.

all the best,


11 replies so far

View pmayer's profile


1028 posts in 3089 days

#1 posted 02-26-2011 02:37 PM

This is pretty common. I have never found one to be flat when I have restored a hand plane, in fact. I just lap with sandpaper placed on cast iron until it is flat. I usually start with something in the range of 320 grit, and work that until it is flat, and then work your way through the grits until you get to 1500 or 2000 and it is polished.

Or, if you want a sure bet, get yourself a Hock blade and cap iron. I just picked one up this week, and so far am quite impressed with the results.

-- PaulMayer,

View tenontim's profile


2131 posts in 3768 days

#2 posted 02-26-2011 03:52 PM

Ditto what Paul said. If you’re tuning these up to use on a regular basis, you’ll be happy with the Hock blades.
I’ve changed all of mine over and it makes a nice difference. The blades are usually thicker than the originals, so there’s less chatter. If you’re just collecting, clean the planes up and put them back together.

View bigike's profile


4052 posts in 3312 days

#3 posted 02-26-2011 04:12 PM

yea hock blades are the greatest for these planes I have a whole fleet of planes and am on my way to changing over the blades. The other thing that stopped me was getting blades from woodcraft the new pinnacle blades those work great too in the stanley and record planes next I want to try a lie nielsen blade and improved chip breaker but for this and the IBC blade and chip breaker that rob cosman endorses you need to open the mouth a little. As for your problem with the blade start with 180 grit to flatten and work up to 600 or higher depends on how much polish you want on the back which doesn’t matter your goal is to get it flat polish is just for looks I think same thing to flatten the sole of the plane too. This is just the method I use for my planes and chisels for the bevel I use of course a different method but it’s a combination of what rob cosman said and david charlesworth said in their DVDs “The great hand plane revival” & “Hand tool techniques 1-2 plus “prep of chisels”. All in all someone can offer is a method that works for them which don’t work for all. GOOD LUCK!

-- Ike, Big Daddies Woodshop,

View CharlieM1958's profile


16275 posts in 4242 days

#4 posted 02-26-2011 04:56 PM

I’m going to ask a really stupid rookie planing question here…

If the cutting edge of the blade is honed properly it should be perfectly flat where edge meets wood. Does it really matter if the rest of the iron, behind the cutting edge, is not 100% flat? I can see where WAY out of flat might be a problem, but I’m not understanding why a few thousandths would make a difference.

-- Charlie M. "Woodworking - patience = firewood"

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17423 posts in 3030 days

#5 posted 02-26-2011 05:35 PM


If the iron is pretty well out of shape you cant start at a much coarser grit. I have had a few where the angle was seriously incorrect and had to regrind it to an acceptable angle. I started with 150 grit on plate glass and worked up to 2000 grit. It takes a while no doubt about it. I also wrote in sharpie on the back of the iron as to the angle i sharpened it at, which helps me when using a honing guide. I feel that if you take it to a machien shop and have the grind it flat you will lose some strength by making it thinner depending on how much material they have to remove. Id also stay away from bending them … im not sure if irons are tempered or not, but bending a tempered piece of steel may cause stress cracks.


I think your idea about the plane iron only really needing to be flat where it meets the wood is correct. It hsould also be close to flat where it mates with the frog. My assumption being that if its not flat against the frog you might create some chatter. I know during my last round of sharpening i really concentrated on the area closest to the edge. So far my refurbished planes are working the best I have ever used, which isn’t a lot, but im getting some really nice shavings.

-- Its not a crack, its a casting imperfection.

View David Kirtley's profile

David Kirtley

1286 posts in 3021 days

#6 posted 02-26-2011 05:49 PM


It really doesn’t make any difference—except If the iron does not fit up against the chip breaker and gives it some room to vibrate or let shavings slip between the iron and chip breaker.


Yes, you will be there forever trying to flatten with a 1000 grit waterstone. The trick is to go through the grits like Ike mentions. Coarse grits for shaping, fine grits for polishing. That said, I doubt that that is really your problem. As it is showing up on more than one iron, It is more likely that your stone is not flat and a bit of crowning of the stone is causing the problem. Waterstones need to be flattened regularly. It doesn’t take that much to see a difference.

I love the blades that Ron Hock makes for other reasons but I can’t say that I would toss out a perfectly good blade to upgrade. I would pay the premium price to replace a bad blade over a standard replacement blade. It is a once in a lifetime replacement for the plane.

-- Woodworking shouldn't cost a fortune:

View Francisco Luna's profile

Francisco Luna

943 posts in 3417 days

#7 posted 02-26-2011 05:59 PM

Avoid Stones for that process. Stones do not stay flat. Sand Paper on a flat surface – 1/2” thick glass or a Granite Slab, woodcraft sales one- is the right way to go. Those Stanley blades are so thin, lots of chattering when planning…..I know hock irons are spensive, but perhaps you can do your own ones…’s not rocket science!

-- Nature is my manifestation of God. I go to nature every day for inspiration in the day's work. I follow in building the principles which nature has used in its domain" Frank Lloyd Wright

View groland's profile


183 posts in 3435 days

#8 posted 02-26-2011 08:41 PM

Thanks to all respondents.

Charlie, I think the blade has to be dead flat on the surface under discussion here because, if it is not, the chipbreaker will not be tight against it and the chipbreaker will not function as it should as shavings will get caught in it.

I do flatten my waterstones religiously with a coarse diamond plate so I am not inclined to believe my waterstones are not flat enough.

I am getting a little sick of flattening, so I think replacement blades and chipbreakers are probably the way to go here. Has anyone got an opinion on replacement blades and chipbreakers from Hock vs. Lie Nielsen? Prices seem about the same for A2 replacements?


View swirt's profile


2773 posts in 2995 days

#9 posted 02-26-2011 09:17 PM

Doesn’t Charlesworth show his ruler trick in his DVD? Its his trick, I would have thought it would be on his DVD. Use his ruler trick to flatten and hone the non beveled side of the blade just 1/16” behind the edge. Unless the blade is dramatically misformed, it will give you enough to make perfect shavings and save you a ton of time in the process.

-- Galootish log blog,

View swirt's profile


2773 posts in 2995 days

#10 posted 02-26-2011 09:20 PM

View groland's profile


183 posts in 3435 days

#11 posted 02-26-2011 10:30 PM

Dear Swirt,

Thanks for your good council on this aspect of plane sharpening. You are correct that the DVD s show the ruler trick—quite a bit in fact, and if that were all that was involved I’d do what you suggest—may do so anyway until the new blades get here. Chatsworth’s care about flattening the back of the blade is partly about getting a good fit with the chip breaker. If the blade back isn’t flat and the chip breaker doesn’t fit it precisely, there can develop problems. He covers fitting chip breakers with care and mentions that many problems people have with hand planes are due to ill-fitting chip breakers.

Fascinating stuff this.



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