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• #DRILL SIZE FOR 5MM TAP SERIES#

Metric dimensioning is routinely used for drill bits of all types, although the details of BS 328 apply only to twist drill bits.

#DRILL SIZE FOR 5MM TAP SERIES#

There are also Renard series sequences of preferred metric drill bits: This subsetting of standard sizes is in contrast to general practice with number gauge drill bits, where it is rare to find a set on the market which does not contain every gauge. Drill bits of the less routinely used sizes, such as 2.55 mm, would have to be ordered from a specialist drill bit supplier. Sets are not commonly available in smaller size increments, except for drill bits below 1 mm diameter. In 0.1 mm increments, any engineers' store. In 0.5 mm increments, any hardware store.

Sets of bits in 1 mm increments might be found on a market stall. Bits at size increments of 1 mm are most commonly available, and lowest price. The price and availability of particular size bits does not change uniformly across the size range.

This reflects both the smaller drilled hole diameter tolerance possible on smaller holes and the wishes of designers to have drill bit sizes available within at most 10% of an arbitrary hole size. In smaller sizes, bits are available in smaller diameter increments. For example, British Standard BS 328 defines 230 sizes from 0.2 mm to 25.0 mm.įrom 0.2 through 0.98 mm, sizes are defined as follows, where N is an integer from 2 through 9:įrom 1.0 through 2.95 mm, sizes are defined as follows, where N is an integer from 10 through 29:įrom 3.0 through 13.9 mm, sizes are defined as follows, where N is an integer from 30 through 139:įrom 14.0 through 25.0 mm, sizes are defined as follows, where M is an integer from 14 through 25: Standards organizations define sets of sizes that are conventionally manufactured and stocked. Metric drill bit sizes define the diameter of the bit in terms of standard metric lengths. The case that holds them in an indexed order (by size), via a graduated series of holes, is called a drill index. Metric drill set, 1.0–6.0 mm by 0.1 mm, jobber length.