Here's what seems to be a neat device shown in Production Machining magazine.
New Vista Corporation has developed a hand-held thread verification unit for the rapid inspection of internal or external threads in production parts. The TVU-HH powers a thread gage into and out of (or onto and off of) the part. The unit reverses automatically when the correct thread depth is reached. ?Go? gaging, ?no go? gaging, and combination gaging are all possible. Three models will inspect thread sizes M3 to M50.
The unit is designed for applications where there can be a variety of part types and thread sizes. Threads are checked successively using a variable speed motor, which is powered by a battery pack; most all thread inspections take no more than 3 seconds. Gage changes are accomplished by using a quick-change toolholder. ======================================================
You'd probably have to check a LOT of threads to make this puppy pay for itself. But it might come in handy for those aerospace jobs that require a 100% inspection of EVERY part.