handplane blade are chipping. Please and thank you.

[Vladimir]

Perhaps this is a little off topic, so I hope you don't mind and can help me with this. I suspect I know the answer but need a little feedback.
I made my own handplane blades from A2 tool steel, hardened to Rc 59 and 61 with a 25 degree bevel. The bevel and the blade (flat) was ground on a grinder from a machine shop (this may be my problem). When I plane an oak board I get minute chipping along the cutting surface almost immediately. Is my grinder creating too much heat and hardening/softening the cutting edge? Should I slow down the feed rate? Do I have to avoid the grinder? What grinding speed and wheel do you recommend?

What are your recommendations. Thank you.

Vlad

 

[Mike Conner]

Were the blades tempered or drawn back after heat treat? If not they are to brittle and are prone to chip on the edge as you are describing.
Mike

 

[Nikk]

I also got some A2 for plane irons but I haven't made any yet. I would appreciate hearing more about what you've learned. How did you harden and temper the blade? I wonder about the standard instructions to soak A2 at high temp. for several hours. Isn't this bad for edge tools?

 

[Matt Shade]

Are you honing the blades after you grind them? It sounds like you have the right hardness, A2 is pretty tough. I would try taking a hard arkansas stone or a ceramic stone and honing the the edge at a 30 degree angle after you grind it. That will smooth out the edge and eliminate any microscopic teeth that are left after grinding.They can make a blade seem sharp, but break off as soon as you start cutting. Honing at a steeper angle gives you a very fine secondary bevel that will make the edge stronger without hurting its cutting ability.

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I may not be the sharpest knife in the drawer... but I've got the sharpest knife in the room.

 

[Vladimir]

Thanks to all.

I hope I can answer some of your questions. The blades were professionally heat treated. A2 is not soaked in oil it is air cooled, if I'm not mistaken. I put on a secondary bevel of 27 degrees. I'll try a secondary bevel of 30 degrees and report back tomorrow. These blades were manufactured by my brother who is doing me a favour. If you have any further questions please email me directly.

Regards,

Vlad (Canada)