tapping drill size

[steve williams 3Participant @stevewilliams3]

[steve williams 3Participant @stevewilliams3]

could anyone please tell me the tapping drill size for a 1/4 32 tpi thread

cheers steve

[NJHParticipant @njh]

Hi Steve

 

5.7mm in my book

 

Cheers

 

Norman

[steve williams 3Participant @stevewilliams3]

cheers norman

its now in my book

steve

[TerrydParticipant @terryd72465]

Hi Steve,

 

You might like to download Alan Munday’s Model Engineers Utilities which has a wealth of information and data such as thread details (tapping drills etc) which are invaluable.

 

Download here

 

Terry

[TerrydParticipant @terryd72465]

Hi Steve,

 

You might like to download Alan Munday’s Model Engineers Utilities which has a wealth of information and data such as thread details (tapping drills etc) which are invaluable.

 

Download here

 

Terry

[TerrydParticipant @terryd72465]

Hi Steve,

 

You might like to download Alan Munday’s Model Engineers Utilities which has a wealth of information and data such as thread details (tapping drills etc) which are invaluable.

 

Download here

 

Terry

[NobbyParticipant @nobby]

Hi

How about a Zeus book Metris addition

Regards Nobby

[John Stevenson 1Participant @johnstevenson1]

Has he written three utilities terry ?

 

Sorry couldn’t resist 

 

I must agree with terry though in that there is some very good information in these utilities, well worth having loaded on a shop computer.

 

John S.

[TerrydParticipant @terryd72465]

Hi John S,

 

Unfortunately no, only one set as far as I know.  It was just one of those days when the website gives an error message after posting so one sends it again, I’ve learned my lesson now.  

 

Seriously with these utilities one needs a reference book as much as one needs a slide rule nowadays, as long as you have a workshop computer or old, bashed up laptop limping along.

 

Best regards

 

Terry.

[JasonBModerator @jasonb]

NJH are you sure its 5.7mm. In my books thats the size for 1/4×40, for 32tpi you want 5.3mm.

 

Didn’t think Zeuz had ME sizes in it.

 

J

 

Edit just realised this is 6months old, why bring up an old post?

Edited By JasonB on 15/01/2011 11:04:05

[KWILParticipant @kwil]

Hang on Jason, Nobby has to get his forum post numbers up somehow!

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Jason, no, Zeus dosen’t have ME in my copy. However, MEW data cards say 5.7mm, and on the back of Tracy Tools catalogue it has No 3 drill which is 5.4mm. So there seems to be some differance of opinion.

 

Regards Nick.

[Chris TriceParticipant @christrice43267]

Tubal Cain quotes 5.5mm for 85% thread engagement to 5.75mm for 60% engagement. The recommended is 5.65mm although I’d drop it to 5.6mm without fear of overstressing the tap. Remember Zeus tables assume a perfectly rigid commercial set up with new cutters and excess torque safety features. If you read the WPS book on the subject, the reasons for drilling very slightly larger than the Zeus figures becomes apparent and valid. Neither does it appreciably weaken the resulting thread but you’ll break far fewer taps.

[MICHAEL WILLIAMSParticipant @michaelwilliams41215]

The tapping size for any normal Whitworth form thread is given by :

 

       Diameter  less ( 1/TPI ) for an average 80% engagement ..  

 

So for 1/4-32     :    1/4 less (1/32) = 7/32 inch or if you prefer 5,56 MM

 

[TerrydParticipant @terryd72465]

Hi Michael,

 

That is as near as dammit as given on Alan Munday’s utilities (5.54mm).

 

T

[JasonBModerator @jasonb]

My tracy says 5.3mm, thats what was to hand this morning. Just looked at the table I use down in the workshop and that has 5.6mm, didn’t think my threads were that sloppy

 

J

Edited By JasonB on 15/01/2011 13:31:49

[Chris TriceParticipant @christrice43267]

If you guys can find a 5.54mm or 5.56mm drill……

 

Go for 5.6mm.

 

I think there’s a good chance of locking the tap up at 5.3mm. Remember there’s an element of extrusion when tapping a thread, not just a clean cut. That’s why you can drill something, tap it but then find you can’t pass the original drill bit through the tapped hole.

 

Edited By Chris Trice on 15/01/2011 16:34:25

[NobbyParticipant @nobby]

Hi

Whoops

Nobby

[WeldsolParticipant @weldsol]

I don’t know how they worked it out but GLR site give 6.4 as a tapping drill size.

Double Whoops

Paul

[Alexander13Participant @alexander13]

I bought a steel ruler from toolstation and it had tap and drill sizes marked on the back.

[Dougie SwanParticipant @dougieswan43463]

A long time ago we were promised a reprint of the old ME data wallchart, with all of this info

Still waiting

Dougie

[KWILParticipant @kwil]

All this Data is available handily on laminated Workshop Wallchart from Myford, pick one up at a show for a couple of £.

[David Clark 13Participant @davidclark13]

Hi There

We reprinted all of these in Model Engineers’ Workshop about 2 1/2 years ago.

regards David

[Dougie SwanParticipant @dougieswan43463]

Hi David,

In may 2009 you said that the ME wallchart would be uploaded to this site so that it could be printed off, I havent been able to find it so far.

If they were repinted in MEW that dosent help those of us who only get ME

Regards

Dougie

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