tap, die charts

[chris mcnicollParticipant @chrismcnicoll83540]

[chris mcnicollParticipant @chrismcnicoll83540]

hi has anyone got a link to a chart that shows drill sizes for metric threads and also pipe/bar sizes for cutting external threads with a die please?

thanks

chris

[Thor 🇳🇴Participant @thor]

Hi Chris,

Does this help for metric threads?

 Here's another. Harold Hall has a page  with tapping drills giving various thread depths.

Thor

 

Edited By Thor on 28/07/2016 15:00:42

[John Stevenson 1Participant @johnstevenson1]

You don’t need charts for metric. The tapping size is the diameter less the pitch so a M6 x 1 is drilled 6-1=5mm

[Martin ConnellyParticipant @martinconnelly55370]

Tapping size for metric is nominal size minus pitch. eg M6x1 is Ø5mm. In reality Ø5.1 will be ok as well but easier to tap.

Martin

Beaten by one second!

Edited By Martin Connelly on 28/07/2016 15:03:18

[chris mcnicollParticipant @chrismcnicoll83540]

So if I'm wanting to cut M12x1.75 thread on some rod, what size do I need to turn the rod down to in the lathe?

Thanks

[Thor 🇳🇴Participant @thor]

Turn the rod down to 12mm or may be 0.1mm or so under size.

Thor

[Martin ConnellyParticipant @martinconnelly55370]

The British Standard for metric threads has a deviation from nominal for class e fit (the sloppiest fit) for a pitch of 1.75mm of -71 micrometers so not far off Thor's 0.1mm figure.

Martin

[Howard LewisParticipant @howardlewis46836]

For a tapped hole drill to 10.25mm, (12 – 1.75), probably 10.3mm will be the nearest easily available.

For many other sizes there are charts available from folk like Chronos, The Tap and Die Co., Tracy Tools and possibly the most comprehensive, if you can find a copy, the Model Engineer Data Sheets. (These cover BSW, BSF, UNC, UNF, BA, Metric Coarse, and the Model Engineer 32 and 40 tpi series).

If you find yourself ever needing to screwcut some thread with an oddball pitch , read off the thread depth form one of charts for that pitch and apply it to the one that you are making, even if the diameter does not correspond to that of the thread chart that you have consulted. This is what you would do if cutting a thread to fit onto a lathe mandrel, of say 8 or 12 tpi Whit form.

Howard

[roy entwistleParticipant @royentwistle24699]

Is the Zeus booklet still available ?

Roy

[Michael GilliganParticipant @michaelgilligan61133]

Posted by roy entwistle on 28/07/2016 18:08:04:

Is the Zeus booklet still available ?

.

Yes

Try putting "zeus engineering tables" into google search.

MichaelG.

Edited By Michael Gilligan on 28/07/2016 18:26:53

[speelwerkParticipant @speelwerk]

Here is another **LINK** direct from the continent so should be OK. At the bottom of the page you find a link to metric fine threads.

I must add that below 10 mm diameter I still use the 0.8 x diameter formula which I learned many years ago, it works fine for me.

Till recently you could still buy drill sets in steps of 0.5 mm but with 3.2 and 4.8 mm added as extra. Niko.

Edited By speelwerk on 28/07/2016 19:01:55

[Ian S CParticipant @iansc]

Neil could probably put a chart in MEW every two or three years, I'v got one from years ago hanging in the workshop next to the lathe.

Ian S C

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