Metric Screw Checker - Large

This (and its smaller brethren) are among the most vital tools that I own. Because UTS machine screw thread pitch is expressed in threads-per-inch, whereas ISO screws go by millimeters-per-thread, you can't determine the true identity of an unknown machine screw without accurately defining shaft diameter and thread pitch. This is what you need for the larger (= 8mm) sized ISO screws.

Like the smaller gauge, this one is also excellent and heavy duty. Again, what more can I say, other than it's made in the U.S.A. which makes me happy.

Now own all models sold by Thread Tool. Dont use them every day but when the need arizes I cherish the day I decided to purchase these tools. LOVE THEM Thank you Thread Tool for these wonderfull time savers. Rob Marquis

As with the Metric Screw Checker: Small, this is a very well made tool. It has a good variety of thread pitch for each size screw or bolt. I highly recommend this tool.

Wasn't raised on metric. This is a necessary tool.