What Is Actually in a 13, 19, 25 and 99-Piece Drill Bit Set

A drill index is sold on its piece count and judged on its sizes. Nineteen pieces sounds better than thirteen until the customer discovers the set stops at 10 mm and the job needs 12. Worse, almost no standard set contains 4.2, 5.1, 6.8 or 8.5 mm — the four tap drills that get used more than anything else on the rack. Here is exactly what is in each standard configuration, and what that means for anyone buying them by the carton.

The standard metric sets, size by size

The 13-piece is a household set. The 19-piece is the volume seller worldwide and the right default for a hardware counter. The 25-piece is the one workshops buy, because 10.5–13.0 mm is where hand-drilled bracket and clearance holes live. The 99-piece is a quantity set, not a range set — its value is that the 2–3.5 mm bits, which snap most often, come several deep.

From our range

Industrial 19-Piece HSS M2 Twist Drill Bit Set (Bright Finish, 1-10mm)

19-piece M2 HSS, 1–10 mm bright finish — the configuration that moves fastest at retail.

From our range

Industrial 25-Piece HSS Twist Drill Bit Set (1.0-13.0mm, Index Case) – OEM

25-piece 1.0–13.0 mm in an index case — the workshop set, covering the sizes the 19-piece stops short of.

Imperial index sets: 29, 60 and 115 piece

The 115-piece index is the complete imperial system in one case, and outside a toolroom it is mostly ornamental — most of its 115 holes never get emptied. In India, Pakistan and the Gulf a metric set plus six loose gauge sizes covers the same work for a fraction of the shelf space and the tied-up cash.

Which sizes run out first

Watch any index case in a working shop and the same holes are empty. Three groups, for three different reasons:

• 2.0, 2.5, 3.0, 3.5 mm — breakage. Small bits snap when the drill is levered or the workpiece moves. Nothing to do with quality; it is leverage and a thin core.
• 4.2, 5.1, 6.8, 8.5, 10.2 mm — consumption. These are the tap drills for M5, 1/4-20, M8, M10, M12. Every threaded hole in the shop passes through one, and none of them is in a half-millimetre set.
• 5.0, 6.0, 7.0, 10.0 mm — masonry crossover. Customers reach for the twist drill sizes that match wall plug colours even when they should be using a masonry bit, and blunt them on brick.

That list is a stocking plan. Sell sets, but keep the nine sizes above as loose singles beside the till, and the replacement business follows the set sale instead of walking to the next shop. It is the highest-margin shelf in the drill section for exactly this reason.

What separates a good index from a returned one

• Shank tolerance (h8). Bits that will not seat properly in a keyless chuck slip under load. This is the single most common cause of "the bit is bad" complaints, and it is a shank problem, not an edge problem.
• A case that closes after use. Sounds trivial; it is the top return reason on cheap sets. Bits go back in warm and slightly bent; a tight moulded case then will not shut and the customer blames the set.
• Size marked on the shank, not only on the case. Once the bits leave the case, unmarked ones are guesswork — and unmarked bits get put back in the wrong hole, which makes the whole index unreliable.
• 135° split point on anything above 5 mm. A 118° point needs centre punching; a split point starts on the mark. On a retail counter this is the demonstrable difference between two sets that look identical.
• Consistent finish. Mixed bright and black bits in one case reads as a repacked assortment, whether it is or not.

From our range

Industrial 99-Piece Titanium HSS Drill Bit Master Set (Metal Case) – OEM

99-piece titanium master set in a metal case — the presentation-grade index for counters where the case does the selling.

Buying sets for retail versus for a workshop

These are two different products that happen to share a name. A retail set is judged on the case, the piece count on the label and the price point; it will be opened in a shop by someone who wants it to look like value. A workshop set is judged on whether 10.5 to 13.0 mm are there, whether the shanks run true, and whether singles can be reordered when four sizes empty.

A distributor stocking one and selling it as the other loses either way — the workshop customer returns the retail set as incomplete, the retail customer finds the workshop set expensive and plain. The split that works: 19-piece bright HSS for retail, 25-piece with a 135° split point for trade, M35 cobalt 13-piece for anyone naming stainless, plus the nine loose sizes above. That is four SKUs covering nearly the whole drill counter.

We build sets to that split, in your own case and branding if you want it — mixed cartons of sets and loose singles ship in one consolidated container, so the reorder sizes arrive with the sets instead of six weeks later. Send the mix and we will quote it in 24 hours.