Mortise Chisel Sharpening

I have a number of antique mortise chisels from ebay etc, all of which had a good bit of use before I bought them. I was interested to see that they generally had just the sort of macro camber (Paul’s term) that Paul recommends for all chisels. That is, they had the gentle curve (with no primary or secondary bevel) that Paul teaches us to create when hand sharpening. I did buy one rather expensive new mortise chisel by Ray Iles. Nice, but probably not worth the money. It came with a long, narrow primary evil of about 20 degrees. According to Tools for Working Wood, where I bought the chisel, that is historically accurate and is there so the chisel can be driven deeply. But it does leave a very fragile edge. So they recommend adding a secondary bevel of 35 degrees to strengthen the weak edge. (Oh, keep in mind that if you put that 20 degree primary bevel on with a wheel, the tip will turn out less than 20 degrees, even if the over all bevel is 20 degrees. That is very weak indeed.) I myself just hand sharpened it in Paul’s fashion and in short order it came to have that macro camber. Hope this helps.