Cutting Tool Selection Guide

Modular Drills: How Replaceable-Head Drilling Lowers Cost per Hole

Modular drills D12–32 mm: replaceable heads, interference-fit assembly and TiAlN coating — how distributors cut cost per hole in batch steel, alloy and cast-iron drilling.

The problem with a solid drill in batch work
A solid carbide drill is efficient — until it wears. Then the whole tool is reground or replaced, the machine waits, and a distributor has to stock a separate drill for every diameter. In batch drilling of steel, alloy steel and cast iron, that is where cost per hole starts to climb. A modular drill changes the unit that wears: the steel body stays in the spindle and only the carbide head is replaced.
How a modular drill is built: interference fit + angular plane location CutStars' modular drill range covers D12–D32 mm for malleable steel, alloy steel and cast iron. Three construction details from the product table are what a buyer should check first:
  • Interference-fit assembly with angular plane location. The head seats on an interference fit, located by an angular plane. That is the detail that decides whether a replaceable-head drill holds dimensional accuracy and cutting safety — a loose or poorly located head shows up immediately as hole-size drift.
  • Ultra-fine grain carbide with a TiAlN-based PVD coating. The fine grain structure and the thermally stable TiAlN coating are specified for higher cutting speeds, which is the point of the system: the head is a wear part, so it is built to cut fast and be changed fast.
  • Excellent chip control and high wear resistance. Chip control is listed as a feature in its own right, not an afterthought — in a D12–D32 hole, a packed flute stops a batch line just as surely as a worn edge does.
Longer and larger: the second variant The range is not one size fits all. A second modular drill entry in the same table covers longer and larger specifications for a wider range of working conditions, with high-feed capability to improve efficiency, a strong, rigid connection seat, and easy insert/head replacement. For a distributor, that is the batch-production argument: the same body system covers standard holes and the longer, larger holes that would otherwise need a separate solid drill — and the head change, not a full tool change, is what the operator does between jobs.
When to recommend a modular drill — and when not to Recommend a modular drill when several of these are true:
  • Hole diameters in the D12–D32 mm range, in malleable steel, alloy steel or cast iron.
  • Batch or repeat production, where head changes happen often enough that changeover time matters.
  • The customer is already buying solid drills by the dozen for the same diameter range — the stocked item becomes heads, not whole drills, so inventory gets simpler.
  • Higher cutting speeds are wanted without giving up hole accuracy. Do not recommend it as a straight replacement for a small solid drill: below D12 mm, the solid carbide drill range (D3.0–D20.0, 3D/5D) is the matching product, and for holes deeper than the modular range's intended depth, the U-drill or crown drill is the deep-hole answer. A distributor who knows that boundary will not oversell the modular drill into a job it was not built for.
Cost per hole, in plain terms The saving is not in the price of one head. It is in three places a buyer can check on their own shop floor: the body is not thrown away when the edge wears; the head change is quicker than a full tool change and reset; and the stockroom holds heads for several diameters instead of a complete drill for each one. No single percentage is claimed here — the user has not confirmed a cost-per-hole figure for this range — but those three are the mechanics, and they are the questions to ask a customer who is comparing a modular drill with a solid drill on price alone.
A short selection checklist for a quote Ask the customer for these five facts and the modular-drill choice narrows quickly:
  1. Hole diameter (D12–D32 mm) and depth — and whether a longer/larger variant is needed.
  1. Workpiece material: malleable steel, alloy steel or cast iron.
  1. Batch size and how often the head will be changed.
  1. Machine and spindle — and whether high-feed drilling is part of the cycle.
  1. What they use today: solid drills, U-drills, or another replaceable-head system — and what wears first, the edge or the body. With those five, CutStars can confirm the head, the body and the connection seat for the job.
What to ask CutStars for Distributors and importers can request the modular drill catalogue and parameter table, the D12–D32 head range, and the longer/larger variants for high-feed batch work. Enquiries are accepted by WhatsApp, the website form and email (info@cutstars.com).