So I've taken on the task of getting a set of 6 Irwin brand chisels in work= ing order for a friend of mine. These must be the former Marples, as they'= re pretty much identical. But not totally. I have a 10 year old set of Ma= rples, and I don't recall the factory grind being quite so poor, especially= the primary bevel. It's practically toothed. Not so sure about steel qua= lity. The backs aren't flat really either, but this I recall was the same = with the Marples. The 1.25" took some fairly serious effort even with fres= h 120 on a granite surface plate.
Just as an aside, I wouldn't say I'm a big fan of my Marples. They're quit= e top heavy, and I actually drilled out a bunch of holes in the handle of m= y 1" to improve balance. And they are also in reality metric, not imperial= . Which is not the system we use at work. And since I've been acquiring g= ood quality antique chisels I've noticed that I'm not real impressed with t= he edge retention. =20
Just my two cents. JP