Advice with a cutting iron

[Florin]

I have this old plane that I wanted to try so I sharpened the iron. I didn't noticed anything stranged while sharpening but the iron had like a grove specific to the tools sharpened on grinding wheel. A tiny mark like a scratch came up when polishing so I tought is just a scratch. But when I tried the plane on a piece of wood it become.a crack. And also the cutting edge gone. So my conclusion is that the blade was overheated on the wheel and now is to hard.
Anyone had same problem? And most important, how do I sort it out, please?
Many thanks.

 

[Jacob]

Looks like a laminated blade perhaps? They sometimes come apart.
I'd just ignore it and carry on sharpening until it is usable, but avoid overheating. Worst of all for this is small diameter grind wheel so you have to keep on dipping in water.

 

[Florin]

Looks like a laminated blade perhaps? They sometimes come apart.
I'd just ignore it and carry on sharpening until it is usable, but avoid overheating. Worst of all for this is small diameter grind wheel so you have to keep on dipping in water.

It would`d be a major problem but is a Norris iron and I thought this cannot be right if it happens. I will sharpen it again. I use diamond stones so I should finish to take of that crack in few days

 

[D_W]

I have this old plane that I wanted to try so I sharpened the iron. I didn't noticed anything stranged while sharpening but the iron had like a grove specific to the tools sharpened on grinding wheel. A tiny mark like a scratch came up when polishing so I tought is just a scratch. But when I tried the plane on a piece of wood it become.a crack. And also the cutting edge gone. So my conclusion is that the blade was overheated on the wheel and now is to hard.
Anyone had same problem? And most important, how do I sort it out, please?
Many thanks.

This isn't a sign of overheating - overheating would make the steel soft and the edge would roll.

I can't say for sure why you have a crack, but look carefully at the other side of the iron and see if it goes longer than just the bevel - you may be able to polish the back further and see it - coarse work on the back of the iron may temporarily obscure it. It may be an artifact from original manufacture or it could be impact from the grinder - I've never seen that happen, though - it would have to be a very large somehow fixed-to-the-wheel large particle.

None of the old laminated irons other than perhaps the revilo irons will air harden, but many of the older irons could develop a crack in heat treatment. You'll find out through use if the crack remains after it's subsequently reground and honed for a while. You can use the iron, but the edge will always chip on both sides of the crack and leave lines on work - if the crack is significant and remains.

 

[D_W]

Looks like a laminated blade perhaps? They sometimes come apart.
I'd just ignore it and carry on sharpening until it is usable, but avoid overheating. Worst of all for this is small diameter grind wheel so you have to keep on dipping in water.

This is inaccurate other than avoiding overheating as general advice.

 

[spanner48]

That's what happens when you resharpen to a single bevel on a powered wheel.

I was taught to grind to a 15º bevel on a treadle-powered wet wheelstone, then finish to 25º by hand on an oilstone, spending more time on making sure the reverse face was completelty flat, than on on the sharpening bevel.

Do that, and you'll not have any troubles.

 

[D_W]

This isn't a matter of grinding to a single bevel on a powered wheel. The iron is cracked either from impact or from too fast of a transition in heat treatment.

But the broken bits at the edge make it look like impact. There won't be anything that big on a grinder unless the iron is somehow caught.

Separating the grinding and final honing angle is good policy, though. Spending adequate time on the back side is also good policy - I haven't seen that done too often when people send me tools to fix or fit.