Magnetic chucks are tools specially designed to hold metal, iron, or ferro-metallic workpieces. These tools must be kept in perfect condition, to perform an ideal job. That is why it is necessary to know in detail how to grind a magnetic chuck.
The basic function of these magnetized tools is to act as fastening systems in work areas related to machining, mold factories, and machinery factories, among others.
This kind of magnetic tool is used to hold workpieces for cutting, grinding, milling, or lapping.
Structure of magnetic chucks
The structure or constitution of a magnetic chuck consists of several components.
On the one hand, these tools have a magnet face, which in addition to being permanent, is precisely centered. On the other hand, they have pole pieces or fixed plates located in a casing, which make contact with permanent magnets or electromagnets. Usually, these pole pieces are flush with the housing surface.
The workpiece that is held with the chuck is responsible for closing the loop or magnetic path on the fixed plates, which provides a completely safe anchor on the said piece.
The magnetic clamping system of these tools can considerably optimize the grip of magnetic steel materials.
Why grind a magnetic chuck?
Although many times the rectification of a magnetic chuck is overlooked, it is an essential task, if you want to obtain adequate results when using the chuck.
Regardless of the type of magnetic chuck you use, you must ensure that it has a perfectly flat surface. It depends on this that the workpieces lie ideally flat.
If your chuck is deformed or has arcs in some areas of its surface, it will be impossible for you to obtain perfectly flat pieces.
Due to all this, it is necessary to know how to grind a magnetic chuck, and how to do it in the best way. For this, you need to take into account the instructions that come with the chuck and know how to operate a precision surface grinder.
It is also important to keep in mind, that the surface grinding process is exact and it should not be improvised. Failure to follow the steps necessary to perform the task correctly can lead to more work or incorrect results when using the magnetic chuck.
How to grind a magnetic chuck on a surface grinder
As we already mentioned, it is important to follow the instructions to carry out the grinding process, especially when working with a surface grinder.
Failure to follow instructions can result in loss of work and time. In addition, it can lead to frustration by not getting the desired result.
On the other hand, you should know that this work requires a lot of patience on your part since it must be done meticulously, and with great care.
Preparations for grinding a magnetic chuck
• Locate a wheel of wide thickness with an open structure. It can be a 46 H or G grain aluminum wheel, whose structure is open. Coarser grit wheels are available but are rare on the market.
• Place the preparation diamond on the left side of the wheel. This will ensure that you are using a sharp face of the diamond, and not a dull or round side. By applying the sharp side of the diamond, you can get sharp particles on the grinding wheel, to cut the magnetic chuck.
• Coats wheel quickly for a coarse finish. This process is known in the industry as an "open dress."
How to use coolant in the grinding process
This is another step that you must know as part of the process of how to grind a magnetic chuck.
Because magnetic chucks are made of steel and aluminum, it is best to use a flood coolant if using a wet grinder. You must open the valve so that the refrigerant flows freely and there are no heating problems.
If you use a dry grinder, the most recommended is to use a kerosene-based oil. Kerosene is perfect for non-ferrous metals, such as those that are part of a chuck. Apply the oil over the entire surface of the chuck with a brush, or with a spray bottle. You should do this every time you run the grinder over the surface of the magnetized tool. Otherwise, the wheel may burn the chuck due to direct friction.
Although it may seem like a complicated job, grinding a magnetic chuck can be done in approximately two hours or less. This is possible by following the steps indicated and taking into account all the recommendations.
Starting the magnetic chuck grinding process
Once you have prepared everything you need to carry out the rectification work, you can proceed with it.
• Before applying the kerosene or the coolant, lines must be drawn with a marker in the areas of the mandrel that present unevenness or concavities.
• Next, the magnet should be turned on. This step is essential; otherwise, the grinding job will not work.
• You must remove the rear rail from the chuck.
• You can then start grinding from the back of the chuck, right in the area below the back rail. This applies in case you leave a chop when raising the wheel, after overhauls.
• Important: No attempt should be made to remove more than 0.0001 inches with each grinder application. Otherwise, you will need to do a lot more work and it will take longer to grind your magnetic chuck.
• Continue with these steps until you have a completely flat mandrel.
Another aspect that you must take into account is that you will have to coat the wheel several times since aluminum clogs the pores over time.
By following these steps and taking into account the advice indicated, you will be able to rectify a magnetic chuck without any inconvenience.
Rectification test
To validate that you have properly learned how to grind a magnetic chuck, you can validate the process with this simple test.
• Get five identical small pieces of steel, and make sure they are the same thickness.
• Place one piece in each corner of the chuck, and one in the center of the tool.
• Carefully grind down each side and check on the faceplate using a dial indicator.
• Mark each of the pieces to know where they were on the tool.
• This way you can validate how flat your magnetic chuck is.
• If it does not have the appropriate rectification, you must rectify it again.
Types of magnetic chuck
Magnetic clamping instruments can be classified according to their shape, configuration, and application. However, no matter which type you use, it is essential that you know how to grind a magnetic chuck.
The type of these tools are the follows:
Circular magnetic chucks
These chucks feature ceramic magnets to provide high-level clamping as well as the easy release of the workpiece.
Units are usually composed of steel and brass top plates. They also feature a concentric ring that provides maximum coolant resistance as well as excellent accuracy when centering workpieces in the chuck. This composition guarantees a long useful life for the magnetic tool, even if it is frequently re-sharpened.
On the other hand, the circular magnetic chucks also include removable handles. This type of mandrel can be obtained in the market configured in standard post mode, or fine mode.
In our online store, you can find out in detail the Circular Lifting Electromagnets for Steel Scraps model, and all its capabilities.
Regarding their application or use, they are mainly used to hold workpieces in internal, rotary, or cylindrical grinding machines, and lathes. They are best suited for holding thin ring-shaped objects, which may be subject to radial distortion.
There are also extra top plates, which can be placed on the chuck, to be machined and adapted to a specific workpiece.
Rectangular Magnetic Chucks
Like all models of magnetized chucks, the rectangular ones have been created to provide high performance in the execution of work, and of course, regarding their holding capacity.
This type of chuck, like the circular ones, has upper plates of steel and brass, to have resistance to coolant. The magnets used by these models of chucks are made of ceramic since these provide greater grip and great ease when releasing the workpiece.
At GME we offer you the General Rectangular Electro-Magnetic Chuck, a highly resistant and effective model.
You can get them in standard poster presentations, or fine posters.
Rotating or rotating magnetic chucks
This type of chuck is made up of posts that are externalized from the edge of the tool. They operate in the same way as rectangular-type chucks.
The top plates of this tool are made of brazed magnetic steel and non-magnetic stainless steel. Both pins and screws can be inserted into its top plate, to resist the high torque used in grinders, lathes, and other machinery with heavy lathe cutting.
On the other hand, the upper plates of the chuck can be machined to carry out special jobs. An auxiliary plate can also be added or removed, leaving the original plate intact, to perform other jobs.
Post mandrels
These types of chucks come in two types: the transverse pole chuck and the longitudinal pole chuck.
In the transversal model, the posts go from side to side of the mandrel, crossing it. The space between the poles is different between one chuck and another. In other words, the space is minimum in mandrels of small dimensions, and maximum in mandrels of large size.
In the longitudinal post model, the posts go from one end to the other, drawing a path along the chuck. In addition, the top plates of the two chucks are furnace welded, thus converting the magnetic and non-magnetic steel into a solid, hermetic unit.
Permanent magnetic chucks
For the manufacture of the standard pole permanent magnetic chucks, high-power ceramic magnets are used.
In addition, magnetic and non-magnetic stainless steel is furnace-welded to obtain a high-strength, single-unit constitution. On the other hand, the magnets can be drilled to the depth that is required.
It is between the poles or any other location on the top where the machining or drilling takes place. There are no magnets on the top plates. Permanent magnetic chucks have removable handles.
Regarding the application of these mandrels, they are used to cut metals. They are usually working instruments in machining centers, and grinding machines, and are used in conjunction with milling and engraving machines, in drilling, iron cutting, and other mechanical processing equipment.
As one of the most requested chuck models in our store, we have the Permanent Magnetic Chucks For Milling Machine Chuck.
Some models of this type of chuck have really strong holding power, and their magnetic force can overlap. Its magnetism increases as the workpiece approaches the chuck.
On the other hand, there are also permanent magnetic chucks whose rigidity and stability are high. Some do not generate heat or deformation due to use, which allows for high-level precision.
Likewise, other designs of this chuck have a simple and mechanical switch, to avoid depending on an electrical power source. In this way, any type of accident due to an unexpected power failure is avoided.
One of the most notable features of some models is that they allow you to quickly and easily replace the clamped workpiece, significantly optimizing the effectiveness and efficiency of the task.
Fine Pole Precision Permanent Magnetic Chuck
Regarding this type of magnetic chuck, there is the possibility of having optional pole steps, which can be:
• Fine pole pitch (0.5 + 1.5 mm),
• Normal pole pitch (1 + 3 mm) or
• Ultra-fine pole pitch (1 + 0.5 mm).
Through the handle of the tool, you can have total and easy control of the clamping and releasing of the workpieces or objects.
This chuck can be used in various grinding machines, line cutting, EDM, bench drills, tapping, and other processes.
Electro permanent Magnetic Chucks
This type of chuck includes all the features and benefits of permanent magnetic chucks.
It consists of a work device that can be classified as new, whose design and development combine the properties of permanent magnets and electromagnets.
In addition, they have an electronic on-and-off system, to activate and deactivate the tool, and to have control over its magnetic power. This minimizes heat buildup and distortion of the workpieces.
Thanks to on/off electrical pulses, the tool requires less than a second to clamp or release. It is an extremely safe and reliable work instrument. If there is no electricity supply, the magnetic power of the chuck will be maintained indefinitely.
Electropermanent magnetic chucks are the perfect alternative for grinding workpieces, both large and small, and can be used for milling small, carving, and medium-sized jobs.
Among the wide variety of magnetic chucks that we have, we offer you the Electro Permanent Magnet Chucks for The Milling Machine, a model of high resistance and versatility.
Thanks to its power, control, and ease in the execution of work, these chucks are constantly used in mechanical processing, plastic processing, mold processing, shipbuilding, and automobile manufacturing, among others.
In the area of machine tools, their uses are also diverse and can be used in machining centers, vertical lathes, injection molding machines, mold clamping machines, engraving machines, milling machines, and other machine tools.
Regarding the applicable processing methods, the electro-permanent magnetic chuck can be used inside drilling, end milling, round bar end milling, multi-part combi milling, slotting, face machining, pocket machining, through-hole machining, contour machining, horizontal milling, boring, three-position die machining, angle and reverse angle milling, welding processing, irregular workpiece processing, and much more.
Electromagnetic chuck for surface grinding machine
Electromagnetic chucks are the most common clamping tools on a surface grinder, thanks to the excellent properties of steel that minimize precision changes during work.
It is important to note that some models of this type of chuck have a waterproof treatment that guarantees the safe use of undercutting fluid for an extended period.
On the other hand, in most of these chucks, the magnetic pole space can be configured taking into account the requirements of the work, to obtain a precise grinding of objects.
Magnetic Chuck for Lathe
This tool is specially designed to fix the work object in a lathe and make it rotate around an axis of rotation to perform various operations such as turning, grinding, cutting, deforming, drilling, and trimming.
There are various models of this type of chuck on the market, designed to perform specific tasks on a lathe. Some are great for polishing; others are perfect for grinding, and some for cutting. They also vary according to the shape or size of the work pieces.
All of these types of magnetic chucks are specially designed for specific tasks. Each one must be properly cared for, so you must properly learn how to grind a magnetic chuck.