Review on 🔧 S12M SDUCR07 SDJCR1212H07 Carbide Turning tool with DCMT21 51 insert by Joseph Hall

Like many other tools made in China, the boring bar and tool holder are very well made. They are hardened (I haven't measured the hardness yet), have a gloss black oxide coating and the insert fits snugly in the pocket. I don't use them for precision turning, so I can't comment on the repeatability of the insert seats. The biggest surprises were the included inserts; I've never heard of this brand, but have since ordered a few different types of them because they look (and work) like inserts that cost over $10 each. They are double coated, the sides are ground and the bottom is lapped. I measured the length and thickness of all 10 and they were all within 0.0002 inches of each other. The way I see it I got a good discount on some good inserts and got the tool holders for free.