size of bit

ArloInt · Aug 29, 2011

Is there a chart that gives the size of bit to use for drilling a hole for a giver size bolt. example for a 8-32, or 6-32, or even larger sizes. would like to be able to take a know size bolt and find the proper bit to have it fit right the first time. guess I'm tired of guessing. Thanks

Gun guru · Aug 29, 2011

The chart you are referring to is a Tap drill chart. Google it and you should find one. Or look for the Machinery handbook online.

Or go on the Starrett website and see if they have a tap drill chart.

2 Cyl partsinfo · Aug 29, 2011

http://www.efunda.com/designstandards/screws/tapdrill.cfm

I just typed in tap drill sizes and this came up. Should answer your questions.
Quality hardware stores often have tap drill charts printed on plastic and often give them away if you buy something.

Anonymous-0 · Aug 29, 2011

The diameter of a "number" screw or "bolt" is .013 X the number plus .060 . Fractional bolts should be no problem All you have to do is add a clearance factor of your choosing. Usually 1/64.

HTH

Areo

JMS./MN · Aug 29, 2011

In a machine shop setting, if the print says "X" "clearance" hole, it is typically 1/64 larger.

bob15 · Aug 30, 2011

see attached
Machine Screw table

teddy52food · Aug 30, 2011

If you have a drill bit index, just try the bolt in the holes & use the next bigger bit.

ArloInt · Aug 30, 2011

I like the info that I have reeived, Printed in out and now have it in my shop. Is going to be handy. Thanks again.

size of bit

ArloInt

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Gun guru

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2 Cyl partsinfo

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Anonymous-0

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JMS./MN

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bob15

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teddy52food

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ArloInt

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