Contact

Corrections are the most useful thing you can send. If a number here disagrees with a chart you trust, I want to know.

[email protected]

What to include

If you are reporting a wrong number, these four things make it quick to check:

• The page, or the thread size.
• The field: tap drill, percent of thread, clearance hole, and so on.
• What the site says, and what you believe it should say.
• Your source, if you have one. A tap maker's chart settles most of it.

Other things worth writing about

• A thread series you need that is not here yet.
• A chart that does not print cleanly on your paper size.
• Anything that reads as confusing or ambiguous.
• Accessibility problems. Those get fixed first.

There is no form

This is a static site with no backend, no database and nowhere to store a message, which is also why it sets no cookies of its own. Email is the only channel. See the privacy policy for what that means for your data.