Thread checking

[mklotz]

I suppose this is more a hint than a tool but it's still a useful device that should be valuable to novice machinists.

In modelmaking one makes a lot of threaded parts and, as a consequence, acquires a large collection of taps and dies. Whenever I encounter a new thread and need to buy threading tackle, I buy two taps and a die for the required size. I use the tap to make a nut and then adjust the die to make a stud that is a smooth running fit in the nut. These test pieces go in a pill vial, along with the taps and dies. The cap of the vial is Sharpie-marked (black for inferial and red for metric) with the thread designation, and tap drill for 65% thread depth (makes threading easier and reduces tap breakage). A large 'LH' in green is added for left-hand taps and dies.

If one encounters an unidentified thread, there are numerous ways to identify it. If it's a male bolt/screw, thread checker plates, e.g.,

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can work but they often don't cover the smaller or seldom-used sizes and, more importantly, are impossible to use if the threaded stud is attached to machinery that blocks the rotation of the checker. Nut and bolt checkers, e.g.,

Nut & Bolt Thread Checker (Inch & Metric) - Tap And Die Sets - Amazon.com

suffer similarly in size coverage.

I could dig my test pieces out of their vials and use them as checks but that's too tedious for me. So I put together a plate with a nut and bolt sample of all the sizes I encounter...

In the case of bolts not in my collection (e.g., the very uncommon 5-44), I simply make another set of checkers using the tap and die in my collection. Since I have a fairly large fastener collection, this happens very infrequently.

A personalized set like this covers several points. Any nut or bolt can be removed and taken to the questioned thread for checking plus its presence in the set proves that I have the necessary threading tackle to make whatever is required, male or female.

Make yourself one of these; it will save you both time and aggravation.