Frederick,
I've had all three for some years now. I use them constantly. I use the curved ones more, especially for curved surfaces on woodturnings. The first photo shows the two rounded ones with another curved scraper I made myself, the second has one in action, the third shows all three:
scrapers_platter2_IMG_20171111_161724_603.jpg _scrapers_IMG_7499_e.jpg SCRAPERS_StewMac_IMG_20171019_081858_098.jpg
I don't use the one with the straight sides as much. I'm experimenting with rounding the corners so they won't dig in. Unlike conventional cabinet scrapers, you don't bend these in use which lifts the corners slightly off the surface. I'll probably round three of the four corners, leaving the lower right to get into tight corners.
scraper_ground.jpg
I sharpen them on a 600 grit CBN wheel at 90 degrees. Yes, they are trivial to sharpen IF you set the platform to the right angle the first time. To aid in setting the platform at precisely 90 degrees at the point of grinding I devised a plexiglas gage. I make these for a variety of grind angles for turning tools and NRS; the white paint on the back of the plastic makes them easier to find read the markings. Look at the difference.
_scrapers_IMG_7809.jpg hand_scraper_setup_IMG_7898.jpg
I think they are well worth the cost and should last a lifetime. I use many rounded scrapers and the StewMac are sometimes more useful in certain situations.
I forgot to mentioned that I love the way they are shaped, with the central area (which they color black) machined concave. This makes them far easier to hold in the hands. Each has a nice hole for hanging on a nail.
I asked them once if they had considered selling the set of three for a discount and they said “no”.
I bought some 1/8” thick O1 oil hardening tool steel with intentions of cutting some additional curved shapes but haven’t found the time yet. (I haven’t forgotten you, Richard D.!)
BTW, they answer to Stewart MacDonald as well as StewMac. Years ago their web site was full of the two-word name but it looks like they shortened it to a catchier and more easily remembered name presumably for branding recognition. However, they still use Stewart MacDonald on some of their products, such as:
https://www.stewmac.com/luthier-tool...cdonald-epoxy/
JKJ