Shopsmith Forums

Apparently all thread depths are not created equal. I usually have no issues with that in the automotive repair industry.

I usually avoid using a tap or die to determine thread size and pitch. I have a really good tap & die set and even those bind a little at the point the tapered threads become non-tapered. I think it's just the nature of the beast. I'd be willing to bet if you drill and tap a hole, a bolt will slide into it like glass.


You may indeed have a defective tap, but nothing stated so far makes me think so.

To properly determine if a thread meets dimensional specifications requires not one, but two precision gages, commonly known as go/no-go gauges. The "go" gauge must go on freely to full depth. The "no-go" gauge must not go on more than a specified amount, maybe 1/2 turn if memory serves. A good thread is one that passes both tests.

Taps, bolts, etc, can determine if you are in the ballpark, but are not definitive.