Bill Tindall, E.Tn.
I ordered a 1/2" Narex mortise chisel for evaluation.
If you are not embarrassed by having a $20 chisel in you bag this chisel is an acceptable candidate for a mortise chisel.
As received: It appeared nicely made. It arrived with an oval handle with a nice unvarnished grip. Blade was finely ground with sharp edges and flat where it should be. Blade is tapered just enough to release in a deep mortise. Blade was lacquered with something that was not hard to remove by abrasion. (It was insoluble in anything I had on hand.) Bevel was ground at a surprising 25 degrees.
Tuning it up: It took about 20 min to flatten the back and bevel, remove an annoying ding on the corner and sharpen. I added a small additional bevel at 30 degrees. It sharpened like the steel is as abrasion resistant as our typical blade steels. It is certainly harder to grind than Sorby or the Blue handled affairs.
In use: The oval handle enabled it to steer well when chopping. It penetrated well. The tapered blade released easily. Edges of the mortise were shaved sufficiently smoothly by the sharp blade edges. I would prefer a bigger striking area on the top. I suspect I will cut off the ring. To test its robustness I whacked it harder than typical, chopping a 1 1/8" deep mortise in this poplar. It felt up to the task prying out chips, again stressing it more than typical. If it was going to fail I wanted it to fail sooner than later. It held up.
Post evaluation: After the mortise chop I examined the edge with 10X magnification. There was no chipping. There was some deformation which was cured by a quick trip to a 1 micron diamond plate. I may increase the microbevel up past 30 degree for the next trial.