Why Do Drill Bits Create Costs Beyond Their Purchase Price?

The price of a new drill bit is only one part of its total cost of use. A dull tool can extend drilling time, reduce hole quality, increase rework and make the operator’s task more difficult. When the required size is unavailable at the right time, downtime or the use of an unsuitable substitute can add further cost.

The impact is often more noticeable with larger-diameter drills, HSS-Co drills, special tools or drill bits used in serial work. Not every worn drill should be sharpened, but many still have sufficient usable length and material condition to return to service after proper reconditioning.

• the cost of buying new drill bits;
• time spent finding a replacement or waiting for delivery;
• workstation downtime;
• the cost of poor holes, burrs and rework;
• higher machine load when a worn tool is used;
• tool waste from discarding bits that could still be restored.

What Is a Drill Sharpener?

A drill sharpener is a machine used to restore the geometry of a drill bit’s cutting end. Depending on the model, it may guide the tool in a holder, set a suitable point angle, restore relief surfaces and, in selected designs, enable web thinning or split-point geometry.

A good sharpener does more than simply grind the tip. It should help preserve the symmetry of both cutting edges, correct geometry and concentricity. These parameters determine whether the sharpened drill will run stably and produce a hole that meets process expectations.

The application range depends on the machine. Some sharpeners handle standard HSS twist drills, others can also be suitable for cobalt drills, while solid-carbide tools may require a dedicated sharpener and the correct grinding wheel.

How Can a Drill Sharpener Reduce Costs?

1. Longer useful tool life

When a drill is merely dull and has no cracks, excessive loss of length or damaged shank, its geometry can often be restored. This can allow the tool to be used for more than one service cycle and reduce the frequency of new-tool purchases.

2. Less downtime

An in-house sharpener allows a rapid response when a tool stops performing correctly. An operator or designated employee can prepare a drill on site instead of waiting for a delivery, external sharpening service or a change in the production schedule.

3. Better drilling quality

A correctly sharpened drill can improve entry stability, hole-surface quality and chip evacuation. This may reduce the risk of burrs, overheating and dimensional errors, although final results also depend on the machine, workholding, feed, coolant and workpiece material.

4. Lower process load

A dull drill usually requires greater feed force and can generate more heat at the cutting zone. Regular tool inspection and reconditioning help maintain a more predictable process and reduce the risk of workpiece damage.

5. Less tool waste

Reconditioning drill bits that still qualify for use supports more rational material use. It does not eliminate the need for replacement tools, but it can reduce cases where a bit is discarded solely because it has become dull.

How to Assess Investment Value

The payback from a drill sharpener depends on each company’s operating conditions. Compare the machine cost with the realistic number of drill bits that can be safely and correctly reconditioned during a given period. Do not assume that every tool is suitable for sharpening or that every bit can be restored an unlimited number of times.

A simple calculation can help:

Monthly net benefit = avoided cost of new drill bits + value of reduced downtime − labour cost − grinding-wheel and consumable cost − service cost.

Then compare the sharpener purchase cost with the monthly net benefit. The greater the number of correctly reconditioned drills and the higher their unit value, the shorter the potential payback period may be. Include training, setup time and quality checks in the calculation.

When Does an In-House Sharpener Make the Most Sense?

A drill sharpener is particularly worth considering where drilling is a regular operation and the company uses a repeatable range of tools. This includes metalworking shops, production departments, maintenance teams, repair businesses, toolrooms and service workstations.

The greatest potential benefits may arise where:

• drill bits wear regularly and the same sizes recur frequently;
• the plant uses larger-diameter or higher-value drill bits;
• tool-delivery lead time affects job completion dates;
• specific sizes need to be available quickly;
• an employee can be trained to set and inspect sharpening correctly;
• the application uses standard geometries supported by the selected machine.

Where drills are used only occasionally, have unusual geometries or require highly specialised precision, outsourcing or purchasing new tools may be the better solution. The decision should follow process analysis, not the sharpener price alone.

How to Choose a Drill Sharpener

The selected machine should match the drill types used in the business. Maximum diameter and purchase price matter, but so do geometry range, drill material and repeatability of setup.

Diameter range

Check the minimum and maximum drill diameter supported by the sharpener. Compare the range with the tools used most frequently, not only with the largest drill stored in the toolroom.

Types of drills to be reconditioned

Confirm whether the machine is intended for HSS, HSS-Co, solid-carbide drills or only certain tool types. Solid-carbide drills require suitable grinding technology and wheels.

Supported angles and geometries

A typical drill-point angle does not suit every application. Different materials and processes may need different angles and geometries. Verify whether the machine provides adjustment and symmetrical sharpening of both cutting edges.

Grinding wheel and consumables

Select the grinding-wheel type for the drill material in line with the sharpener manufacturer’s instructions. Availability, cost, replacement method and quality consistency over repeated cycles are all important.

Setup and quality inspection

The machine should support repeatable tool positioning. Clear settings, compatible collets or holders and quick verification of the sharpening result matter in daily work.

Safety, service and training

Check guards, grinding-dust control, availability of consumables and service support. Operators should be trained in machine use, geometry selection and recognising when a drill must be removed from service instead of sharpened.

Common Drill-Reconditioning Mistakes

• Sharpening every worn drill without selection: cracked, excessively shortened or shank-damaged tools should be withdrawn according to the company procedure.
• Uneven cutting edges: this can cause runout, uneven holes and excessive load on one edge.
• Wrong point angle or relief: this reduces cutting performance and tool life.
• Using an unsuitable grinding wheel: this can lower sharpening quality and damage the tool.
• Skipping post-sharpening inspection: assess geometry, cutting-edge condition and trial drilling in representative material.
• Working without protection or dust extraction: grinding requires appropriate protective measures and workstation rules.

FAQ

Can every drill bit be sharpened?

No. Reconditioning depends on the drill material, design, condition and the sharpener’s capability. Cracked, heavily damaged or too-short drill bits should be replaced.

How many times can a drill be sharpened?

There is no single number. It depends on usable flute length, wear level, required geometry and the quality of previous sharpening. After every cycle, assess whether the tool still meets process requirements.

Can a sharpener be used for cobalt drills?

That depends on the model and grinding wheel. Confirm the drill materials supported by the machine in the manufacturer documentation before purchase.

Does sharpening replace the need to buy new tools?

Not completely. Sharpening extends the usable life of some tools, but it does not remove the need for new drills where there is damage, unusual geometry or very high precision requirements.

How can I check whether the investment will pay off?

Compare monthly drill consumption, tool costs, reconditioning potential, labour and consumable costs, plus the cost of downtime. This produces a more reliable assessment than comparing the sharpener price with the price of a single drill bit.

Summary

A drill sharpener can be a highly valuable item of equipment where drilling is a regular process and the business uses tools with recurring diameters and meaningful unit value. It can help reduce new-drill purchases, shorten downtime and support drilling quality.

Payback is not automatic. It depends on consumption scale, sharpening quality, operating cost and correct machine selection. The best results come from combining a suitable sharpener, trained personnel, geometry control and clear rules for withdrawing tools that should not remain in service.