Review on E-Z Lok EK51210 Metric Helical Threaded Insert Kit, High-Quality 304 Stainless Steel, M16-1.5 Thread Size, 16 mm Installed Length (Pack of 5) by Demetrius Patsion

I've used the smaller EZ-Lok kits (smaller threads) successfully, but this larger 14MX1.5 kit had a poorly made tap that wouldn't start even with the right one Oil drain hole in the Crankcase of my VW. Upon closer inspection, the initial threads on the flutes of the tap appeared dull. I tested it on a 3/8 piece of aluminum and was able to run the faucet but it gouged the hole pretty hard. If I had continued I would have ruined the crankcase. I had to return the set but did not receive another one for fear of an inferior faucet. I am a retired engineer with skills in machining parts on milling and turning machines.