Flattening Plane Irons

[Andrew Hughes]

That would be a Shapton DLRP.Its very expensive but it does have too sides one for stones and one for steel.Its also bronze and very solid.
The stone side looks like this.

[steven c newman]

I will start out with the hammer, IF needed. I will then use the side of my grinder's wheel. Does not take much time at all. While I am using an upside-down beltsander and a MK1 honing guide to work on a new bevel....I will hold the back onto the belt.

At each stage after that ( oil stones, W&D Paper) I will work the back a few times as well.
Water? I do keep a large cup of water nearby.....

[Archie England]

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.

Okay, that's what I was asking Pete about in an earlier post. Any slight lift of the blade tend to score the blade (or the stone), and it's a little tricky (well, the way I've done it).

[Patrick Chase]

That would be a Shapton DLRP.Its very expensive but it does have too sides one for stones and one for steel.Its also bronze and very solid.
The stone side looks like this.

You do not want to use the diamond ("stones") side for anything but fairly fine waterstones. Shapton's diamond plates are incredibly flat and uniform (none of the "rogue diamonds" that plague DMT), but they're made by resin-bonding the diamonds to the substrate instead of nickel electroplating. If you take steel or a very coarse stone to them you'll strip the diamonds.

Also, when Andrew says "very expensive" he means $550. If you have to ask, you can't afford it.

This is basically the same idea but less exorbitant: http://www.leevalley.com/us/wood/pag...52&cat=1,43072

I use commodity precision-ground 1018 plate from McMaster-Carr, which is cheaper still.

[Steve H Graham]

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?

I am trying to flatten the cap iron side. Just a little strip near the cutting edge.

[Andrew Hughes]

What stones or steel did you use that stripped off the diamonds?
I do remember Stanley mentioning not to try and flatin a Hard Arkansas because it wouldn't be good for the stone side.
I also have the diamond on glass and I like it better because it's light.
Thanks for the heads up.

[Matthew Hutchinson477]

I feel your pain, Steve. I too have no suitable power tools for flattening metal. I've restored more than a few hand planes and chisels using only non-powered hand tools. For plane blades, a diamond stone worked better for me than sandpaper. I tried silicon carbide grit before, too, but that requires a suitable surface like a dead flat piece of steel or a piece of plate glass you don't mind destroying. I tried using a beltsander once to at least get a couple blades close while getting rid of the pitting but the blades always ended up slightly convex rather than flat, which is about the worst shape you can have. Once a plane blade is rounded like that getting it flat is very difficult no matter what method you use.

So, onto the hammer method. I can attest to it and honestly it's been the fastest, easiest method I've found short of power tools. I think I saw it originally in a Paul Sellers video. It does work but make sure you use a hammer with a big, slightly convex face. A lot of metalworking hammers, like planishing hammers, have faces that are slightly rounded like this. If the face is completely flat you'll either have to hit the blade dead on (which is very difficult to do) or you'll end up putting a dent in it with the edge of the hammer face. Though I think a good metalworking hammer would be ideal, I've done it with a plastic faced hammer before and it worked well enough. If you don't have a dead flat metal surface like an anvil, a dead flat piece of hard wood can work but make sure you hit the blade far enough back from the cutting edge because you will likely end up with a hollow. That was my experience using a hard piece of wood rather than an anvil, at least.

[Steve H Graham]

The 60-grit paper I bought today definitely works faster than the 100-grit I was using yesterday, but on the whole, I wish I had a surface grinder.

I have to check out that Sellers video.

[Patrick Chase]

What stones or steel did you use that stripped off the diamonds?
I do remember Stanley mentioning not to try and flatin a Hard Arkansas because it wouldn't be good for the stone side.
I also have the diamond on glass and I like it better because it's light.
Thanks for the heads up.

There are many acciynts of worn out Shapton plates out there, for example from Chris Schwarz. I have the single-sided version and haven't yet managed to strip any significant # of diamonds, though. I've also never disobeyed the instructions, which say:

• Never use it on steel
• Never use it on any waterstone more coarse than the 500# Glass stone.

Inspection under a microscope revealed that the diamonds are bonded instead of nickel-electroplated, and my experience as an engineer leads me to believe that that's why Shapton imposes the constraints they do. Shapton offers to strip and recoat the plate if you wear it out, but it isn't cheap (a couple/few hundred IIRC).

Even the "best" nickel-based plates are no guarantee BTW. I once stripped most of the diamonds from a Dia-Flat (the plate whose durability Schwarz proclaims) by "enthusiastically" flattening a Sigma Select II #240 with it.

[Patrick Chase]

So, onto the hammer method. I can attest to it and honestly it's been the fastest, easiest method I've found short of power tools. I think I saw it originally in a Paul Sellers video. It does work but make sure you use a hammer with a big, slightly convex face. A lot of metalworking hammers, like planishing hammers, have faces that are slightly rounded like this. If the face is completely flat you'll either have to hit the blade dead on (which is very difficult to do) or you'll end up putting a dent in it with the edge of the hammer face. Though I think a good metalworking hammer would be ideal, I've done it with a plastic faced hammer before and it worked well enough. If you don't have a dead flat metal surface like an anvil, a dead flat piece of hard wood can work but make sure you hit the blade far enough back from the cutting edge because you will likely end up with a hollow. That was my experience using a hard piece of wood rather than an anvil, at least.

I'd be careful about doing that with any really hard plane iron. It's pretty easy to do damage that way. Hardened steel sometimes doesn't take very well to being beaten on with a metalworking hammer.

[Matthew Hutchinson477]

I'd be careful about doing that with any really hard plane iron. It's pretty easy to do damage that way. Hardened steel sometimes doesn't take very well to being beaten on with a metalworking hammer.

Ah, yes, I forgot to mention the importance of tapping gently. With the plastic faced hammer I gave the blades a solid hit but with the planishing hammer it was a lot more light taps. I'm no expert on the subject by any means so please correct me if the metalworking hammer is just a bad idea entirely. It did, however, work for me when I tried it.

[Patrick Chase]

Ah, yes, I forgot to mention the importance of tapping gently. With the plastic faced hammer I gave the blades a solid hit but with the planishing hammer it was a lot more light taps. I'm no expert on the subject by any means so please correct me if the metalworking hammer is just a bad idea entirely. It did, however, work for me when I tried it.

Depends how hard the piece your hammering on is. For typical plane irons at, say, Rc60 light tapping should be fine.

Be sure to wear goggles if you ever do that to a fully-hardened tool like some files though :-)

[steven c newman]

I seem to get a few irons through the Dungeon Rehab Center ....not only do I have to flatten the back, I also have to straighten the bowed iron along it's length...

Ball pean Hammer, and set the bad spot right over the leg of my bench. Same goes for a few chipbreakers. Rather than trying to sandpaper a cb flat enough to mate the iron's back, I wind up using than same ball pean hammer. Then it doesn't take so much removal of metalto fettle the chipbreaker.

2+ hours to flatten an iron's back? You have got to be joking. Takes me MAYBE ten minutes. haven't time to waste on such things. 2 hours? I am glad I am not paying that person by the hour....used to call that kind of worker a Milkman, because he was "milking" the job.

[Archie England]

2+ hours to flatten an iron's back? You have got to be joking. Takes me MAYBE ten minutes.

Steven, I've had a few rehabs that took over an hour for back flattening (and a few more that I just gave up on and used the ruler trick). I've got one Sigma stone that I will no longer put on chisel or plane back because it leaves such deep scratches. This stone is a metal hogger and is fine for cutting and reshaping bevels; but it's way to coarse for a blade back that needs to get relatively flat and free of grooves.

[Patrick Chase]

Steven, I've had a few rehabs that took over an hour for back flattening (and a few more that I just gave up on and used the ruler trick). I've got one Sigma stone that I will no longer put on chisel or plane back because it leaves such deep scratches. This stone is a metal hogger and is fine for cutting and reshaping bevels; but it's way to coarse for a blade back that needs to get relatively flat and free of grooves.

Sounds like the Power #120? In addition to being coarse that stone is also made up of SiC, which adds to its aggressiveness.

With that said it all depends on how far out of flat the tool is. #120 is ~1/10 mm particle size, so if the tool is out of flat by more than a few times that then it can still be faster overall to start with that stone. Put another way, you'll spend much less time on the next stone up to remove 1/10 mm deep scratches than you would flattening a tool that's a few tenths out. A good straightedge and some shim stock are helpful to figure out where to start.