10 Inch Forstner Bit Extension for 3/8″ Round Shank, Hole Saw Extension Chuck, for Adding Over 8-3/4 inches of Drilling Depth

Not all carbon steel is equal. A crude test I use, and certainly not a perfect indicator, is to judge a tool’s robustness by its heft. This extension is a remarkably hefty 6.2 ozs (without wrench or packaging). That heft and the fine machining and smooth finish lead to me judge this bit very high quality and deserving of five stars in the light of the $11.84 price tag. This kind of quality in my view justifies that price for a mere extension bit, because it’s a heavy duty bit suitable for use in high torque drills and difficult materials.That said is it possible an overtorque situation could break this? I think it’s possible but not likely, but I also think with *any* of my other extension bits with their narrower shanks, that breaking those shanks is far more likely. Of course careful drilling should mean never overtorqueing your tool, but we all get tired at the end of a frustrating day and push our tools.This is by far the best extension bit I’ve got, but I do wish the collar had been welded to the beefy shank not just inside the collar but outside as well. I doubt the welds will break but I’d feel more peace of mind if they’d have taken the extra step to double weld. I’d also prefer a stainless steel set screw to the black one provided (presumably carbon steel). I keep extra set screws on hand because they tend to eventually fail so if this one fails I’ll be alright, but it’s annoying for such a high quality bit to have a typical set screw subject to rusting.The other drawback of this bit is that it only accepts 3/8″ shanks. A shame. I wish they would provide an insert for it so it could accept narrower shanks as well. I do have hole saws with narrower shanks and sometimes I need to use them in deep holes requiring an extension.This is a tough product to rate given the very high quality but with noted drawbacks. I’d say overall it’s a 4.5 and round up to five.