How can you cool a drill?
The ideal way to cool
In most drilling operations using carbide
drills,
coolant is supplied through the machine spindle, respectively, through the spindle clamping equipment and the internal channels of the carbide
drill
.
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Why are lubricants needed when drilling metals?
Strong heating during drilling is a serious problem. At the point of contact between the tool and the workpiece, the temperature reaches hundreds of degrees Celsius.
When overheated, materials begin to burn or melt. This applies to both drills and processed metals.
- The steel from which the tool is made loses its hardness when heated strongly. As a result, the cutting edges wear out quickly. This leads to a significant increase in friction force. Because of this, processing efficiency decreases and drills quickly fail. It is necessary to use cutting fluid (coolant) even when using carbide drills.
- Strong heating, if the part begins to melt, will affect the quality and geometry of the hole. This is unacceptable in many cases.
- Another side effect of drilling metal without lubrication is rapid wear of the drilling machine motors. Constant overload leads to it. The result is expensive repairs.
It is these problems that cutting fluids solve.
Note! For cooling, in no case should you use unsuitable means at hand (water, solvents, anti-freeze, alcohol, glass washing liquid, etc.). For example, the use of water instead of the recommended coolants leads to corrosive destruction of workpieces, as well as the working beds of machine tools.
Video description
Lubricating the hammer drill chuck.
When choosing a substance, you need to take into account that, for example, what you use to lubricate a hammer drill is not always suitable for processing a gearbox. For each of the nodes, it is necessary to use the substance recommended specifically for this node.
Applying lubricant to the drill Source srbu.ru
In modern instruments, plastic parts may be used in some cases. Here you cannot use the same means as for metal parts. For this, silicone grease is used.
For tail nozzles, thicker mixtures are used. This is caused by the significant loads that this part of the tool experiences. Usually the packaging indicates whether it is suitable for processing drills. The technician must carefully choose which lubricant to use for the hammer drill.
Detailed diagram of the hammer drill Source burforum.ru
The most popular products for the purposes under consideration are the products of the following manufacturers:
- Makita lubricants are designed to care for drill bits.
- Turmgrease mixtures have universal use.
- Bosch products are suitable for both gearboxes and tail parts of attachments.
- Lubcon Thermoplex lubricants are designed for gearboxes.
- Nanotek products are well suited for lubricating the drill tail.
- The mixture from Kress is used for drills.
The use of branded products must be in accordance with the instructions supplied with them.
The drill shank experiences significant loads during operation. Source zuzako.com
How can I replace coolant?
It is impossible to prepare exact analogues of modern emulsions for machine tools with your own hands, but it is quite possible to replace a number of them using this table:
Here, on a five-point scale, dry cutting is 1 point. If the use of a coolant substitute provides an improvement/deterioration compared to dry machining, points are added/subtracted.
If you decide to replace the emulsion in the machine with a homemade equivalent, thoroughly rinse and disinfect the tank and feed system. This is necessary to avoid problems due to the compatibility of the compositions, to destroy bacteria, fungi and mold. For this procedure, you can use Oilcool XR system cleaners.
Some “home Kulibins” consider brake fluid and anti-freeze to be analogues of coolant. These fluids do have excellent cooling and lubricating properties, but contain substances (methanol, ethylene glycol, propylene glycol) that can cause severe poisoning, disability and even death. Therefore, they cannot replace the emulsion for the machine.
Technology and methodology for drilling stainless steel
The first and most important thing to remember: drill stainless steel only using cooling lubricant and special drills. As for the thickness of the material being processed, the technology provides the following:
- Stainless steel, the thickness of which is within 1–2 millimeters, can be drilled with ordinary metal drills. In this case, the sharpening angle of the tool should correspond to 120 degrees, and the revolutions of the electric drill should not exceed 100 per minute.
- It is better to drill a millimeter-thick or thinner layer of stainless steel using step-type equipment. It provides a smooth channel with no burrs or burrs on the edge.
- It is best to produce holes in stainless steel with a thickness of more than 6 mm using specialized cutters in two stages. First, you need to drill the metal with thin equipment with a diameter of 2–3 mm, and then bring it to the desired diameter with a finishing drill.
If stainless steel shavings begin to acquire dark shades and become small, this indicates that the cutting edges are dull and overheating. It is impossible to work in this mode.
Which is better: prepare coolant yourself or buy factory-made
Hobby metalworkers persistently develop their own recipes for making emulsions for machine tools for various reasons: someone wants to create an analogue of imported coolant, which has disappeared from sale, someone simply likes to achieve the desired results themselves.
Do-it-yourself coolants are cheaper than factory ones, but they are inferior in terms of performance characteristics and service life, and some homemade compositions are also very dangerous to health.
Today, Russian enterprises produce complete analogues of coolant from world brands and publish interchangeability tables, with the help of which you can choose a high-quality and inexpensive emulsion for a lathe. Therefore, you should not conduct risky home experiments with making formulations according to recipes from the Internet.
How to make your own oil-based coolant
To prepare an oil-based emulsion with your own hands, just thoroughly mix three components - oil, water and surfactant (surfactant).
Metalworking forums also offer more complex recipes for making homemade coolant for lathes. For example:
- mix one faceted glass of flavored liquid soap, unrefined sunflower oil, kerosene and soda ash + half a stack of laundry bleach + a quarter stack of Fairy, add warm water to a volume of 10 liters and heat to 90 ° with continuous stirring. Dilute the resulting concentrate with water in a ratio of 1:3.
- 65 liters of water + 7 liters of diesel fuel + 1 piece of grated 60% laundry soap + 1 pack of Pemos Automatic washing powder + 200g of Feri dishwashing liquid (Fairy) + 2 tablespoons of soda ash. After pouring into the coolant tank, run the pump for 10 minutes - and the homemade emulsion is ready.
Industrial oil is often found in recipes for homemade emulsions. It can be replaced with a motor one.
Economic feasibility of using cutting fluids
The use of recommended cutting fluids is completely justified from an economic point of view. This is proven by the results of various tests.
An excellent example is data from the Karnasch plant (Germany). A test was carried out on it in which two core drills were used to make holes with a diameter of 25 mm in steel 10 mm thick. When drilling with the first drill, a 7% emulsion solution was used, and when processing the material with the second tool, water was used. In the first case, it was possible to drill 1,500 holes, and in the second, 835. This is 45% less.
On average, if we take into account the cost of coolant, the economic costs of metalworking are reduced by 15%. At the same time, the service life of the machine is extended. This fact is also worth taking into account.
Popular models of core drilling machines
At MOSSklad you can buy magnetic drilling machines from the best manufacturers in a wide price range for drilling holes with a max. diameter from 25 to 200 mm.
Rotation speed: 650 rpm Max. d-drilling: 16 mm In stock and in the demo room
RUB 37,400
Rotation speed: 400 (775 no load) rpm Max. d-drilling: 6-14 mm Coming soon
RUB 50,688
Rotation speed: 250/450 rpm Max. d-drilling: 16 mm In stock and in the demo room
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Rotation speed: 60-140 and 200-470 rpm Max. d-drilling: 32 mm In stock and in the demo room
Which drill is better to use
List of drills for stainless steel that are definitely suitable for drilling metal:
- Any tool that contains cobalt in its alloy. The higher the percentage of this component, the better. Cobalt products differ from ordinary ones in a yellowish tint. Do not confuse the cobalt alloy with the application of this metal only to the outer part of the drill by electroplating. In the latter case, it will not be possible to drill through stainless steel.
- Expensive specialized tool. Such pobedit drills can drill through stainless steel, not just concrete. They have a certain sharpening angle.
- For thin stainless steel, you can use a feather-shaped drill bit for ceramic tiles. This is not the best option, but it will help to drill the workpiece once.
Application of cobalt drill
Of the old Soviet drills for stainless steel, the most suitable tool would be the one with the brand R6M5K5. This type of equipment contains up to 5% cobalt in the alloy. Due to this element, the tool acquires high strength, and the heating temperature can reach 135 degrees Celsius, which does not entail destruction of the material. Products of this quality can only be found in markets where old Soviet equipment is sold, and even then not always. An alternative to a domestically produced cobalt drill is a foreign analogue under the HSS-Co brand.
To drill stainless steel with a cobalt drill, you should also use lubricants and do not use high speed power tools.
