How to Change the Drill Attachment

In electric drills, a special device called a chuck is used to securely fix the drills. In household drills, the most commonly used cam chucks. If used intensively, they may fail and require replacement or repair. During these operations, problems often arise. So how do you remove the cartridge from the drill shaft, disassemble it into component parts and change it to a new one?

How to Change the Drill Attachment

The role of the chuck in securing the drill

Clamping chucks for household drills are available in three versions:

The body of the key cam cartridge is made in the form of a hollow hardened cylindrical sleeve (collet), on the outer surface of which a rotating adjusting clip is installed. On one side, the cylinder is mounted on the drive shaft of the drill, and on the other hand there are cams (petals) for attaching the cutting tool (drills, taps, reamers, etc.). When the adjusting ring is rotated, steel cams move along the guides with the help of a special thread. If they come closer to each other. The drill is clamped. If they diverge from each other, the tool is released. The approach and distance of the cams depends on the direction of rotation of the cage. Reliable fixation of the drill is ensured by tightening the cartridge holder with great effort. To do this, use a special key or keyless. On keyless chucks. A coupling.

The key helps to tighten the drill bit and easily unscrew the adjusting clip. Drills of various diameters with a cylindrical shank are fixed in cam clamping chucks. Most often, chucks for household electric drills are designed for drills with a diameter of 0.8 to 10 mm or 1.5 to 13 mm.

Why and when do I need to change?

The clamping device must ensure drilling holes with acceptable accuracy. But over time, the seats on the shaft and the cams wear out, the cartridge begins to beat. That is, the working area of ​​the drill begins to rotate from side to side during rotation, and the hole is drilled with deviations both in place and in diameter. The wear on the cams does not allow the drill bits to be firmly fixed, and they stop under load. There is only one way out. To change a worn cartridge to a new one.

How to replace the drill cartridge with your own hands?

A threaded connection or Morse taper is used to attach the cartridge to the drive shaft of the drill. Visual inspection of an electric drill will not always help to suggest a method of securing a drill chuck. The marking on the cartridge can inform about this: it is knocked out on its surface.

Replacing the cone of a part

The size of the Morse cone (according to GOST 9953–82) consists of 9 values: from B7 to B45. The larger the number after the letter B, the larger the diameter of the cone.

Thus, having found the marking “B” on the surface of the cartridge, we can conclude that this is a device with a conical mounting base. With this nozzle method, the cartridge is easily removed. It is enough to use a punch and a bench hammer.

Video: how to remove a cartridge with a cone from an electric drill?

Replacing reverse threaded chuck

To fix the drilling clamping device on an electric household drill using a threaded joint, two types of thread are used:

  • Inch (for foreign models);
  • Metric (from Russian manufacturers).

On the surface of the housing of the clamping threaded cartridge, the following markings are applied: 1.5–13 1/2. 20unf or 1.5–13 M12x1.25.

The reverse threaded chuck for fixing has a left-hand screw. This nuance you need to know when removing a broken cartridge. In order to get to the screw head, it is necessary to completely drown the cams in the collet. As soon as the screw head is visible, you need to unscrew it with a hardened Phillips screwdriver clockwise to the right. Then hold the hex key in the cams and hit it sharply in a counterclockwise direction. After the cartridge is ripped off, it will easily loosen.

Video: how to remove a cartridge from a reverse drill or screwdriver?

On other models, there are other options for attaching the cartridge to the thread. In some cases, the cartridge is twisted entirely from the threaded end of the shaft. In other cases, the screw can be fixed with a special thin key using a narrow groove. The main difficulty is to unload the cartridge when turning off. This is sometimes very difficult to do. In any case, to remove the cartridge you need: a locksmith tool, the necessary skill and patience.

Dismantling the cam chuck of the drill with quick-release nut

To clean the cams, lubricate the moving parts and threads of the cartridge, it must be disassembled. Dismantling is necessary for the repair and replacement of failed parts. Here is a short list and sequence of operations for disassembling the cam cartridge:

  1. The removed cartridge with the conical part up, lined with wooden gaskets, is clamped in a vice by the coupling.
  2. The nut with the notches is carefully unscrewed with a gas wrench.
  3. The bearing is pulled out. He gets the puck.
  4. The cartridge is removed from a vice.
  5. The adjustment sleeve is twisted from the base by hand. If it does not give in (jammed), then the cartridge flips over and again is squeezed behind the clutch in a vice. A little engine oil is poured onto the threaded part of the coupling and base. Then, with a gas wrench, the base is skillfully twisted out of the coupling.
  6. If there is a snap ring or nut below, they are removed.
  7. The cams are pulled out of the guide rings and removed from the base cone.
  8. All parts of the drill chuck are carefully inspected. If worn, deformed, or broken parts are detected, they are discarded and replaced.
  9. The cam cartridge is assembled in the reverse order. At the same time, all moving parts are lubricated with special grease. It is best to use the grease recommended by the manufacturer.

The procedure for disassembling cartridges of other models may be different. It depends on the type of cartridge, its design and the manufacturer of the drill. To independently disassemble the drill chuck, three conditions must be met:

  • Have the necessary set of tools;
  • Have locksmith skills;
  • To be a person with a stable, balanced psyche.

Possible problems with the chuck when operating the drill: causes, description and ways to solve them

To prevent problems with the drill, you need to be able to work on it correctly. A drill is a universal tool, with its help you can drill wood and metal, plastic and tile, stone and glass, concrete and brick. In everyday life, an average power impact rotary drill is usually used. It is equipped with an SDS system cartridge, which was invented by BOSH. The SDS chuck is not particularly accurate, but is ideal for drilling concrete, stone, and brick. That is, those building materials where drilling is needed with a punch.

For more accurate drilling of metal and wooden parts, it has a special adapter for attaching a clamping cam key or keyless chuck. Drills cannot be used for milling. The drill chuck is not designed for lateral loading and will quickly fail. Of great importance is:

  • The right choice of drill;
  • Correct sharpening of the cutting part of the drill;
  • Mandatory marking of the center of the holes with a core.

It is necessary to skillfully use the choice of the desired speed, feed, operating mode, depending on the material of the workpiece. All these factors directly affect the reliable operation of the drill chuck.

Detail flies

Does the cartridge fly off? This problem is quite common even on new drills when tapering the cam chuck when a deep hole is being drilled. It is necessary to raise the drill to free it from the chips, and at this moment the cartridge flies off the cone. Correct the situation by increasing the interference fit in the cone pair. To do this, the cartridge is heated in oil or oven to a temperature of 110 degrees and sits on a cold drill mandrel.

Clamping jams

Drill work always occurs in dirty conditions. This is dust, dirt, shavings, sawdust and other small debris. If trapped inside the cartridge, this debris can seize threaded joints, in particular on cams. There is only one way out. It requires disassembling the cartridge, cleaning and washing the moving parts. Before assembly, all moving parts are lubricated with lithol. Especially a lot of waste is poured into the cartridge when drilling ceiling surfaces. Here you can think about protecting the cartridge with half a small rubber ball.


Runout of a cartridge can be caused by various reasons. For example, the Morse landing cone is worn out. This can be checked with paint. A uniform layer is applied to the cone, a cartridge is inserted. Then the trace that he left on the cone is removed and studied. Another cause may be uneven cam wear. In this case, they need to be changed. But more often they change a broken cartridge to a new clamping device.

In skillful hands, a household drill works wonders. With its help, holes are drilled in strong and soft materials. The chuck is an important part of a drilling machine. It is he who provides the reliability of fastening the drill and the accuracy of drilling. Therefore, it is very important for a home master to be able to independently provide minor repairs and replace this part of the device.