Drill bits are essential tools in workshops, production facilities and maintenance departments. With regular use, they naturally wear out, and replacing them incurs not only the cost of purchase but also downtime, operator time and the risk of task delays.
Drill bits are essential tools in workshops, production facilities and maintenance departments. With regular drilling, they naturally wear out, and replacing them incurs not only the cost of purchase but also downtime, operator time and the risk of task delays.
A drill bit sharpener enables the correct geometry to be restored to selected drill bits directly on-site. Its cost-effectiveness depends on the number of tools reconditioned, their value, the type of production and the quality of the sharpening carried out. In facilities where drill bits wear out regularly, a well-chosen machine can significantly reduce running costs.
Why do drill bits generate more costs than their purchase price?
The cost of a new drill bit is only one element of its total cost of ownership. A blunt tool can prolong the drilling cycle, reduce the quality of the hole, increase the number of reworks and make the operator’s job more difficult. When the correct size is not available at the right time, there is also the cost of downtime or the need to use a substitute tool.
The costs are often most noticeable in the case of larger-diameter drill bits made from HSS-Co, special-purpose drill bits or tools used in mass production. Not every worn drill bit needs to be resharpened, but many of them still have sufficient length and material integrity to be returned to service following proper reconditioning.
- the cost of purchasing new drill bits;
- the time spent finding a replacement or waiting for delivery;
- workstation downtime;
- the cost of defective holes, burrs and rework;
- increased strain on the machine when working with a worn tool;
- waste resulting from the premature disposal of tools that could be reconditioned.
What is a drill bit sharpener?
A drill bit sharpener is a device that restores the geometry of a drill bit’s cutting edge. Depending on the model, it can guide the tool in the chuck, set the correct point angle, correct the contact surface and – in certain designs – enable the core to be tapered or a split-point geometry to be created.
A good drill bit sharpener does more than simply grind down the tip. Its purpose is to maintain the symmetry of both cutting edges, the correct geometry and concentricity. It is precisely these parameters that determine whether the drill bit, after sharpening, will drill steadily and produce a hole that meets expectations.
The scope of application depends on the specific machine. Some sharpeners handle standard HSS twist drills, whilst others are also designed for cobalt drills; carbide tools may require a suitable grinding wheel and a sharpener designed for their reconditioning.
How can a drill bit sharpener reduce costs?
1. Extended tool life
If a drill bit is merely blunt and has no cracks, excessive loss of length or a damaged shank, its geometry can be restored. This allows the tool to be used for more than one life cycle and reduces the number of new drill bits that need to be purchased.
2. Less downtime
Having your own drill bit sharpener allows you to react immediately when a tool stops working properly. The operator or a designated person can prepare the drill bit on site, rather than waiting for a delivery, an external sharpening service or a change to the schedule.
3. Improved drilling quality
A properly sharpened drill bit can improve stability on entry into the material, the surface quality of the hole and chip evacuation. This reduces the risk of burrs, overheating and dimensional errors, although the final result also depends on the machine, clamping, feed rate, cooling and the properties of the material being machined.
4. Reduced process load
A blunt drill bit usually requires greater feed force and can generate more heat in the cutting zone. Regular inspection and reconditioning of tools help to maintain a more predictable process and minimise the risk of workpiece damage.
5. Less tool waste
Regenerating drills that are still fit for use promotes a more efficient use of material. It does not eliminate the need to replace tools, but it reduces the number of instances where a drill is discarded solely because it has become blunt.
How can you assess the return on investment?
The return on investment in a drill sharpener depends on the individual circumstances of the company. It is worth comparing the cost of the machine with the actual number of drill bits that can be safely and correctly reconditioned over a given period. One should not assume that every drill bit will be suitable for sharpening or that every drill bit can be reconditioned an unlimited number of times.
A simple calculation model is helpful:
Monthly net benefit = savings on the purchase of new drill bits + value of reduced downtime − labour costs − cost of grinding wheels and consumables − service costs.
You can then compare the cost of purchasing a sharpener with the monthly net benefit. The greater the number of successfully reconditioned drill bits and the higher the value of the tools, the shorter the payback period may be. The calculation should also take into account the training of the operator and the time required for quality control.
| Elements of the calculation | What to take into account? |
|---|---|
| Drill bit wear | Number of drill bits taken out of service per month, broken down by diameter and type |
| Reconditioning potential | How many tools are merely blunt and meet the criteria for reuse |
| Alternative cost | The price of a new drill bit, the cost of an external service and the waiting time |
| Labour cost | Time taken for set-up, sharpening, geometry checks and tool marking |
| Operating costs | Grinding wheels, sleeves, holders, cleaning and periodic servicing of the machine |
| Impact on production | Reduction in downtime, number of reworks, availability of the correct sizes |
When does it make the most sense to have your own drill bit sharpener?
A drill bit sharpener is particularly worth considering for businesses that carry out drilling on a regular basis and have a consistent set of tools. This includes, amongst others, metalworking workshops, metal fabrication, maintenance departments, renovation firms, tool shops and service centres.
The greatest benefits can be realised when:
- drill bits wear out regularly and their sizes are often the same;
- the workshop uses drill bits with larger diameters or a higher unit cost;
- waiting times for tool deliveries affect lead times;
- there is a need for rapid availability of specific diameters;
- the company has a member of staff who can be trained in the correct setting and inspection of sharpening;
- the application allows for the use of standard geometries supported by the selected sharpener model.
If drill bits are used only occasionally, have an unusual geometry or require a very high level of specialist precision, it may be more advantageous to use an external service or purchase new tools. The decision should be based on an analysis of the process, rather than solely on the price of the sharpener itself.
How to choose a drill sharpener?
The choice of machine should correspond to the types of drill bits used in the workshop. Not only the maximum diameter and price are important, but also the range of geometries, the tool material and the repeatability of settings.
Diameter range
Check the minimum and maximum diameters supported by the sharpener. Compare these with the tools used most frequently, rather than just the single largest drill bit in stock.
Type of drills to be re-sharpened
Determine whether the machine is designed for HSS, HSS-Co, solid carbide drill bits or only for specific types of tools. Solid carbide drill bits require appropriate sharpening technology and grinding wheels.
Supported angles and geometries
A typical drill point angle does not always suit every application. Depending on the material and technology, different angles and geometries may be required. It is worth checking whether the sharpener allows for adjustment and whether it ensures symmetrical finishing of both cutting edges.
Grinding wheel and consumables
Select the type of grinding wheel to suit the drill material in accordance with the sharpener manufacturer’s instructions. Important factors include the availability of grinding wheels, their cost, the method of replacement, and the ability to maintain consistent quality across successive sharpening cycles.
Ease of setup and quality control
The machine should facilitate repeatable tool positioning. In day-to-day work, clear settings, compatible sleeves or holders, and the ability to quickly check the sharpening result are key.
Safety, servicing and training
Check the guards, the method of grinding dust extraction, and the availability of consumables and servicing. The operator should be trained in the operation of the machine, the correct selection of geometry, and how to assess when a drill bit needs sharpening and when it must be taken out of service.
The most common mistakes when reconditioning drill bits
- Sharpening every worn drill bit without selection: cracked, excessively shortened or damaged-shank tools must be taken out of service in accordance with the plant’s procedure.
- Lack of blade symmetry: this can cause runout, an uneven bore and excessive stress on one edge.
- Incorrect angle or contact surface: this impairs cutting performance and reduces tool life.
- Selection of an unsuitable grinding wheel: may reduce the quality of the sharpening and damage the tool.
- Failure to carry out post-sharpening checks: it is advisable to assess the geometry, the condition of the cutting edges and to carry out a test drill in representative material.
- Working without protective equipment and dust extraction: the grinding process requires the use of protective equipment and compliance with the rules specified for the workstation.
FAQ – frequently asked questions
Can any drill bit be sharpened?
No. Whether a drill bit can be re-sharpened depends on the material, design, condition of the tool and the capabilities of the sharpening machine. Cracked, severely damaged or excessively short drill bits must be replaced.
How many times can a drill bit be sharpened?
There is no single figure. It depends on the length of the cutting edge, the degree of wear, the required geometry and the quality of previous sharpening. After each cycle, you should assess whether the tool still meets the process requirements.
Will the sharpening machine work with cobalt drill bits?
This depends on the model and the grinding wheel used. Before purchasing, check the manufacturer’s documentation to confirm which drill materials the machine is compatible with.
Does sharpening drill bits replace the need to buy new tools?
Not entirely. Sharpening extends the service life of some tools, but it does not eliminate the need to purchase new drill bits, particularly in the case of damage, unusual geometry or high-precision requirements.
How can you check whether the investment will be cost-effective?
Calculate the number of drill bits used per month, their cost, the feasibility of reconditioning, the cost of labour and consumables, and the cost of downtime. Such an analysis provides a far more reliable result than simply comparing the price of the sharpening machine with the price of a single drill bit.
Summary
A drill bit sharpener can be a very cost-effective piece of equipment where drilling is a regular process and the workshop uses tools of consistent diameters and a suitable value. It helps to reduce the need to purchase new drill bits, minimise downtime and improve drilling quality.
However, a return on investment is not automatic. It depends on the rate of wear, the quality of the reconditioning, running costs and the correct choice of machine. The best results are achieved through a combination of a good sharpening machine, a trained operator, geometry checks and clear guidelines for taking tools out of service when they are no longer fit for use.
