Flattening Plane Irons

[Steve H Graham]

I have bought 4 planes in the last month, if spokeshaves count. I am getting very familiar with flattening the backs of plane irons.

Yesterday I put in about two hours on a new Stanley spokeshave iron. I was not too happy about it. I used a DMT extra-coarse stone part of the time, but I eventually put 100 grit paper over the stone and used that. Still pretty slow. I am not really content with the results. I believe there is a small area I should continue to work on.

Is there something faster out there, that either stays flat like a diamond stone or is easily trued up?

[Pete Taran]

The easiest way to flatten this kind of stuff is on the side of a wet water wheel. I have 2 tormek grinders. One has the stock 220 grit stone in it, the other the 6000 grit waterstone. You just hold the iron on the side of the stone for 15 to 20 seconds at a time, and it's flat in no time. When done with the 220 grit, switch to the 6000 grit. The whole process takes 5 minutes. It's crazy fast and takes ALL the grunt work out of the process. it cuts fast because the water is constantly removing the debris from the wheel. Short of a surface grinder, this is your fastest route.

I was always skeptical about the utility of those Tormek grinders. They cost a lot and the gizmosity factor is off the charts. However, after buying one, it is the Dog Diggity of sharpening contraptions. Anyone who loves to work wood but hates to sharpen should own one. I was so impressed, I bought another one just so I didn't have to change wheels.

[Steve H Graham]

It's weird that big companies that could do this job for their customers so easily and cheaply shoot their irons out the door with big dips in them.

[Archie England]

Pete T: Please explain a little more about how you hold the blade to the Tormek wheel's side. I've done that a few times to hasten the grinding process but sometimes I get less than satisfactory results.

Steve G: (Don't we all love sharpening threads!!!) I get inconsistent results with sandpaper but still consider the lower grits a great way to remove metal on dished blade backs. However, for consistent results I use very coarse water stones (Cerax 320 and Sigma 400). For me, synthetic water stones, being significantly faster than oil stones, are adequate and somewhat equal to sandpaper in speed (though that's not always true when compared to 80 grit or less sandpaper). I've used up diamond plates a little to quickly, so I'm less willing to use that medium on blade backs now.

However, in watching a Paul Sellers video on rehabbing an old plane, he significantly shortened my sharpening time when he gave a convex blade back a single blow on a flat surface. This actually worked for me because it removed the belly back that would have taken forever to grind down. However, to all those who do this differently, I intend no offense to the numerous other good ways of arriving at the goal. If it works; it must be good.

[Allen Jordan]

The hammering technique is interesting, sounds like it would work well. I sometimes purposefully grind a hollow into older blades to make lapping easier.

[Robert Hazelwood]

The best thing I have found is to get a flat granite plate and stick on some 60 or 80 grit PSA sandpaper. Woodcraft sells a 4"x 18" granite plate for pretty cheap, which makes a nice long sanding block.

I've tried coarse waterstones, diamond stones, oil stones, etc. but nothing cuts faster than a fresh sheet of coarse sandpaper. Just remember to keep the paper fresh, as it seems to remove as much material in the first minute or two of use as it does in the next 10.

Once the back is even on the 80 grit, I can bring it over to the coarse DMT and then the Shapton 1000 to finish the flattening, which doesn't take too long. Then it is ready to move onto the normal sharpening routine.

[Andrew Hughes]

Here's a method that I use when I need to remove a lot of steel.Thats a Finck blade under my right hand A2 steel.I can really bear down with a stick across the back.

[Steve H Graham]

I am going to look into the hammering thing. I don't think it will help me with the iron I'm working now, because it's nearly done. I assume that straightening an iron with one side which has already been partially flattened will make things worse.

Someone just suggested putting a small bevel on the flat side of the iron.

[Allen Jordan]

I am going to look into the hammering thing. I don't think it will help me with the iron I'm working now, because it's nearly done. I assume that straightening an iron with one side which has already been partially flattened will make things worse.

Someone just suggested putting a small bevel on the flat side of the iron.

The ruler trick will pretty much always work, though it's less traditional.

[Steve H Graham]

You know what? I'm going to get some coarse sandpaper. I am seeing some interesting ideas which I may try later, but I feel like getting the two irons I have in front of me fixed today.

The Tormek idea sounds foolproof, but I think an even better idea is to make a friend who has a Tormek and save money.

[Patrick Chase]

I have bought 4 planes in the last month, if spokeshaves count. I am getting very familiar with flattening the backs of plane irons.

Yesterday I put in about two hours on a new Stanley spokeshave iron. I was not too happy about it. I used a DMT extra-coarse stone part of the time, but I eventually put 100 grit paper over the stone and used that. Still pretty slow. I am not really content with the results. I believe there is a small area I should continue to work on.

Is there something faster out there, that either stays flat like a diamond stone or is easily trued up?

I use diamond paste starting at 60 um grit size on cast iron and/or mild steel plates. I have a set of 8" by 4" precision-ground 1018 plates that are particularly nice for flattening. They stay pretty flat, and in my experience it's by far the fastest hand-powered flattening method. It isn't cheap, but neither are sandpaper or DMT plates.

I also have a Tormek, and as Pete says that's a very efficient option with some practice. You have to be very careful not to "rock" the iron on the side of the wheel, but other than that it isn't very demanding.

[Allen Jordan]

Wouldn't the tormek wheel side distort with use? Seems like a flat grinder like a worksharp might work better.

[Pete Taran]

Foley used to make a scissors sharpener which had a cast iron plate and you used grinding compound on it. It worked pretty well, but I sold it when the Tormek came along. A lot faster and less mess. You have to be smart about how you do it. Keep the blade moving along the side of the wheel and press it dead flat. The stone is pretty hard, so it can take the abuse. I haven't noticed any dishing in quite a bit of plane iron work. Works for chisels or whatever else you have that needs sharpened.

[Pat Barry]

I have bought 4 planes in the last month, if spokeshaves count. I am getting very familiar with flattening the backs of plane irons.

Yesterday I put in about two hours on a new Stanley spokeshave iron. I was not too happy about it. I used a DMT extra-coarse stone part of the time, but I eventually put 100 grit paper over the stone and used that. Still pretty slow. I am not really content with the results. I believe there is a small area I should continue to work on.

Is there something faster out there, that either stays flat like a diamond stone or is easily trued up?

When you say back side, which side do you mean exactly? Is that the cap iron side?
How much if the are you trying to flatten? The whole thing or just a portion?

[Martin Shupe]

Here's a method that I use when I need to remove a lot of steel.Thats a Finck blade under my right hand A2 steel.I can really bear down with a stick across the back.

What is the brand of the flattening plate you are using?