ALUX Posted August 14, 2014 Share Posted August 14, 2014 I am not sure what size tap hole I should use for a 9/32 clearance hole. Can anyone tell me what tap hole size I should use? I would also appreciate any recommendations on a good website to learn more about Tapping & Clearance Hole Information. Thank you in advance. Quote Link to comment Share on other sites More sharing options...
ReMark Posted August 14, 2014 Share Posted August 14, 2014 Maybe this is what you are looking for? http://www.csgnetwork.com/screwfracmachtable.html I'd think a machinist's handbook would be most useful to you. Quote Link to comment Share on other sites More sharing options...
Patrick Hughes Posted August 15, 2014 Share Posted August 15, 2014 As a rule of thumb I've always considered a clearance of 1/32 for screws from 1/4 up to 7/16. 1/16 for larger. BTW you reference a "Tap hole size" so I'm merely stating screw size. The tap drill is dependent upon the thread pitch along with other factors. So if your clearance hole is 9/32 then that would work well for a 1/4 screw. Quote Link to comment Share on other sites More sharing options...
nukecad Posted August 16, 2014 Share Posted August 16, 2014 This is an invaluable little reference booklet for tapping/clearance hole sizes along with other workshop data. http://www.stationaryengineparts.com/Zeus-Precision-Data-Charts-and-Reference-Tables.html Don't worry that it says metric edition on the cover, there is imperial thread data (anf, anc, bsf, bsw,etc) in there as well. Every draughtsman I have ever worked with has his own copy. P.S. Check your local bookstore, they may have it at a lower price. Quote Link to comment Share on other sites More sharing options...
SuperCAD Posted August 18, 2014 Share Posted August 18, 2014 A tapped hole and clearance hole are two entirely different things. A tapped hole is one that is large enough for the screw shaft diameter to fit through but small enough to have enough thread engagement when tapped. What is the thread specification that you're trying to use. Quote Link to comment Share on other sites More sharing options...
zaphod Posted August 18, 2014 Share Posted August 18, 2014 A "Machinery's Handbook" is a good thing to have, even an old one. I own at least 3 but the one I keep at my desk is the cleanest, printed in 1959. here is a link I often use, as more and more threads are being "roll formed" http://www.fastenersinc.com/Images/fasteners_tap_drill_chart.pdf Quote Link to comment Share on other sites More sharing options...
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