On 19 June, 19:24, "dennis@home"
wrote:


You are probably overheating it if you are using a grinder to sharpen it.

Which is the reason why it preferable to use a low speed wheel to
sharpen a wood chisel or plane iron before honing it on an Arkansas
stone or similar. Once overheated it is almost impossible for the
average DIYer to restore the correct temper to the chisel/iron.