Ads
related to: 5mm drill bit to fraction
Search results
Results From The WOW.Com Content Network
Drill bit sizes are written as irreducible fractions. So, instead of 78/64 inch, or 1 14/64 inch, the size is noted as 1 7/32 inch. Below is a chart providing the decimal-fraction equivalents that are most relevant to fractional-inch drill bit sizes (that is, 0 to 1 by 64ths).
Example (inch, fine): For 7 ⁄ 16-20 (same diameter as the previous example, but this time with 20 threads per inch, which is considered fine), 0.437 in × 0.90 = 0.393 in (i.e., if the threads are to be fine, then a slightly larger diameter drill bit should be used before tapping the hole for the screw).
where is the tap drill size, is the major diameter of the tap (e.g., 10 mm for a M10×1.5 tap), and pitch is the pitch of the thread (1.5 mm in the case of a standard M10 tap) and so the correct drill size is 8.5 mm. This works for both fine and coarse pitches, and also produces an approximate 75% thread.
The clearance sizes need to be left as drill nomenclature (3/64, 6.5 mm, #37) rather than converting to decimal dimensions since having that dimension you have to chase down the table to find the actual drill that it represents. I believe I can come up with a column arrangement that's easier to understand.
A 10.5 mm brad point drill bit. The brad point drill bit (also known as lip and spur drill bit, and dowel drill bit) is a variation of the twist drill bit which is optimized for drilling in wood. Conventional twist drill bits tend to wander when presented to a flat workpiece.
Exmples (approximate dimensions, for masonry drills: 6 - about 4mm, No. 8 about 3/16 inch or 4.5mm, No.9 about 5mm, No.10 about 5.5mm etc. I cannot find any discussion of this scheme for giving the sizes of drills but it should at least be mentioned as a historical system, in use at least until the 1990s. Thank you.