I am looking for a comprehensive tap and drill chart that covers both US and metric. I ran into a situation at work where a part was purchased that had a metric thread pitch that none of the crappy charts showed. Looking further into this, I realized there are a lot more thread pitches for metric sizes than I previously knew about.
If you have any internet resources or books that have this, please let me know.
Thanks for any pointers.
Stephen R.
Pick up a copy of _Machinery's Handbook_. It will have all kinds of threads, including some of the hybrid ones like "BA" (a UK standard which uses metric pitches and inch diameters, IIRC. :-)
Good Luck, DoN.
Here's comprehensive for you.
Tap drill = diameter minus pitch
Cheers Trevor Jones
If you need to know the size to drill for a metric cutting tap, simply subtract the pitch from the diameter. ie M10x1.25 would be 10 - 1.25 = 8.75.
michael
Actually, I was surprised to discover that my Machinery's Handbook (26th Ed) is missing quite a few metric thread diameter pitch combinations in its tables. Moltrecht's "Machine Shop Practice" lists a number of metric threads that are not in Machinery's Handbook, but the tech data is not given (e.g., pitch diameter, min/max minor diameter, min/max major diameter, etc.). Fortunately, all the equations and reference tables are available in Machinery's Handbook to calculate any desired metric thread. But it would have been nice if the look-up tables were more complete.
- Michael
Thanks for all the info.. Very helpful.
Stephen R.
Look at this free program:
Thanks Mike,
That is a pretty good piece of freeware.
Stephen R.
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