Replacing the screwdriver chuck: features of the screwdriver procedure, its structure and possible malfunctions. Three-jaw chuck and its design. Fastening methods. Thread and tool taper. Dismantling instructions. Disassembly and breakdown options.
Most screwdriver models use three-jaw chucks. The chuck carries the bulk of the load during tool operation. This can lead to frequent malfunctions. The most common problems are:
- Cam play;
- Misalignment of the cam and the clamped element relative to the axis of rotation;
- Uneven tightening torque;
To carry out repairs, it is necessary to find out the cause of the breakdown. To do this, you must first remove the cartridge. Before doing this, you should find out the fastening method. There are two options:
- The tool cone is the simplest and safest method of fastening. This type of connection allows a high torque to be transmitted without the risk of damaging the shaft or chuck bore.
- Threads are easier to manufacture, but less reliable under constant heavy load operation. If the torque is exceeded or the tool is jammed in the drilling mode, the thread can be cut.
To determine the type of fastening, you should carefully study the marking. Typically, the fixing method is indicated immediately behind the shank diameters range:
- In household power tools, for compactness, shortened versions of the tool cones are used, marked with the letter B and a number showing the diameter of the thickest part of the cone in millimeters. Detailed information about the designation contains GOST 995382. This designation will be required in case of purchasing a new cartridge.
- In the case of using a threaded fastener, there will be a metric or inch thread designation.
Device and malfunctions
All screwdrivers have approximately the same device. Certain varieties may include a number of additional nodes. But any model is equipped with the following mandatory elements:
- DC motor;
- Planetary reductor;
- Load limiter;
The most common malfunction is a broken battery. The easiest way is to replace a non-working battery with a new one. If the model is old and the required batteries are not on sale, you can try to adapt the filling from another by placing it in the case from the old one. Care should be taken to ensure that the electrical characteristics of the batteries used for replacement are correct.
Nickel-cadmium batteries have a memory effect. Sometimes, to restore their normal operation, it is enough to carry out several cycles of full discharge and charge. This will restore the battery to its original capacity.
The question of how to unscrew the chuck on a screwdriver is relevant only for threaded fasteners. The removal method in the case of tapered fixation is fundamentally different. It will be necessary to apply shock loads to the cartridge itself, but the plastic case cannot withstand this, therefore, the tapered mount in screwdrivers is extremely rare.
If you had to deal with tapered fixation, you can use the following techniques:
- If there is a gap between the tool body and the chuck, insert a suitable wrench. The horns of the key rest against the base of the cartridge and strike the handle. The tool body can be gently clamped in a vice through a soft gasket.
- If the gap is absent or minimal, you need to find a metal wedge and carefully hammer it between the chuck and the body. Sometimes a special wedge is supplied with the device for this purpose.
If the chuck attached to the cone has a locking screw screwed in from the jaw side, this can aid disassembly. Do not remove the screw completely. After unscrewing it a few turns, you can try to knock on the head. This will require a piece of metal bar and a hammer. With an impact screwdriver, the task becomes even easier, since the blows can be applied directly to the handle.
How to remove and change the cartridge
If you are faced with replacing the cartridge, initially, you should figure out how to mount it. To carry out the procedure with a minimum of effort, experts do not recommend overloading the screwdriver in everyday use. If you operate the tool for fifteen minutes without interruption, the rotating parts may overheat and lock firmly into the socket. Then it will be more difficult to carry out the replacement. Experts recommend the tried and tested methods for removing the cartridge, described below:
- Unscrew the threaded fastener with an L-shaped hexagon, which is sure to be found in every owner. Next, insert the hexagon (size 10 mm), place the short edge into the chuck and squeeze tightly in the jaws. After that, start and immediately turn off the device at low speed so that the free edge hits the table slightly, thus the thread will weaken and the chuck can be unscrewed.
- If the chuck is threaded with a locking screw, then:
- Unscrew the left-hand screw clockwise.
- Then insert the hexagon into the cams, and with a quick movement of the hand or hammer, turn the free edge against the clockwise movement. Now you can unscrew the cartridge.
- If both methods didn’t work:
- We take out the shaft from the open housing, on which the gearbox and the cartridge are located. Use a pipe wrench to remove the cartridge.
- To remove and change a chuck with a Morse taper, you need to have a hammer with you, with which the shank will be released from the housing socket.
Chuck Removal: Makita Screwdriver
Typically, Makita brand power tools are equipped with a threaded fastener with an auxiliary retention using a left-hand screw.
A number of actions should be followed:
- Unscrew the retaining screw (clockwise).
- Activate the spindle stop button.
- Wrap the body with a thick cloth and squeeze in a vice.
- Clamp the hexagon in the cams.
- Striking with a hammer on the free plane of the key, the chuck is scrolled and then removed from the shaft.
How to determine the method of fastening on a screwdriver
The fastening method is easy to recognize if you carefully examine the details. The cartridge of the Morse cone variety will have the following inscription: 1-6 B10. This means that in the chuck, it is permissible to fix nozzles with a shank diameter of 1-6 mm, and B10 is an indicator of the size of the Morse taper.
The cartridge, fixed with a threaded fastener, is marked:
- Metric thread (domestic products) 1.0-11 М12х1.25
- Inch thread (foreign made) 2-13 mm ½-20 UNF
What is the method of clamping
drill chuck is better
In household drills and screwdrivers, one of the types is usually installed according to the method of clamping the working tool of the cartridges, this is with a key and quick-clamping. Key jaw chucks have been around for a long time and are well known to any home craftsman. Keyless chucks have recently come into use and quickly gained a lot of popularity.
In the photo on the left you can see a keyless chuck, and on the right a key with a key. There is an opinion that the key chuck grips drills better, but from many years of experience in operating both the key chuck and the key chuck, I dare to say that there is no difference. Both types of cartridges are clamped with equal success. Only the convenience and speed of changing drills in a drill with a keyless chuck is undeniable. You do not need a key, which is always lost during work, if it is not attached to the drill or tied to it on a rope, you need to use two hands to clamp the drill.
The way the chuck is clamped is not related to the way it is attached to the drill shaft, so if you change the chuck with a key clamping method, I advise you to install a chuck with a quick-clamping method for fixing the drills instead.
How is it fixed
drill chuck on tool
An external examination of the power tool, it is often not possible to determine in what way the drill chuck is fixed. But if you know the markings, then the mounting method will be determined even with a cursory glance at the cartridge.
How to unscrew the chuck from the shaft of a drill or screwdriver
To remove the chuck from the tool, you need to fix the shaft and, grasping the chuck by the housing, unscrew it, turning it counterclockwise when viewed from the side of the cams. The main thing is to rip the cartridge off the ground, then it is usually easily unscrewed.
I was lucky, as there were chamfers on the round base of the chuck, which could be well hooked with an open-end wrench # 19. There were no such samples in the replacement cartridge.
After gripping the chuck with an open-end wrench and one sharp blow on the key with a hammer, even without fixing the shaft, as in the photo, the chuck moved from its place. But it turned off tight, and there was a reason for this. I had to continue twisting it with light blows on the key with a hammer.
Looking inside the cartridge, I did not notice the fixing screw because the hole in the head for the star-shaped bit was clogged with dirt, which just had to be removed. Therefore, unscrewing the cartridge, I simultaneously tore off the thread of the fixing screw, it is strange that it did not break off.
If there are no chamfers on the base of the chuck, then you need to clamp a hex bar or an M10-12 bolt with a hex head in its jaws, onto which you put a key and hit it with a hammer. If you cannot screw the cartridge in this way, then you will have to disassemble the drill, remove the shaft with the cartridge, clamp it in a vice and twist it. Instead of an open-end wrench, you can use a pipe wrench by grabbing the chuck by the outside of the housing.