Low cost belt grinding machine
Tools and MaterialsTools:
- Angle grinder with cutting discs.
- Drill and drills.
- Wrenches for 11, 12 and 19.
- Electric motor (minimum 6 A, or recommended 12 A).
- Different bearings.
- Nuts, bolts, washers, locking washers of various sizes.
- Metal corner.
- Sanding belt 20 cm.
- 10 cm pulleys.
- Powerful spring.
- Became 4 x 20 cm wide strip.
- 2.5 x 10 x 10 cm timber from wood or MDF.
Electric motor for machine toolI had a choice of several motors, but the electric motor that stood on the tile-cutting machine had a more suitable casing. To some extent, the work on the machine was like an experiment, because I was not sure about the sufficient power of the motor. Therefore, I settled on a modular solution with a frame for a tape mechanism as a single element that can be removed and rearranged to a more powerful basis. The rotational speed of the motor was fine with me, but I was worried that 6 A would give poor power. After a small test, I saw that this motor was suitable for simple work, but for more intensive work, you need to choose something more powerful. When designing your machine, pay attention to this moment. As I mentioned, the casing of the electric motor was very suitable, as it allowed you to create a vertical machine that would be easy to move. First you need to release it by removing the desktop, saw, protection, water tray, leaving only the electric motor. Another advantage of using this motor was a threaded core and a nut for fixing the saw, which made it possible to install a pulley without using a key (what is a key,I will explain later.) Since I had a too wide pulley, I decided to use large clamping washers, which usually fix the saw, turning one back side so that there is a wedge-shaped groove between them. I found that the space between them was too narrow, and, in order to expand it, I put a lock washer between them. The advantage of this method is that the clamping washers have a flat edge, which is fixed with a flat edge for simultaneous rotation with the core.
BeltI used a 7 x drive belt 500 mm. You can use the standard 12 mm, but the thinner is more flexible, and it will load the motor less. He doesn’t need to rotate the grinding wheel.
Belt grinding machine
Determining the type of driveThe main issue was to rotate the main pulley directly by an electric motor or by using an additional pulley and drive belt. First of all, I chose a belt drive because I wanted to allow me to replace the engine with a more powerful one, however, there was another reason. When you do intensive metal processing, there is a risk of facing some problems. The belt drive in such cases will slip, while the direct drive will create big problems. With the belt, the device will be more secure.
Making the frame and installing itIt is important to mentionthat the use of a metal corner as a frame can have both advantages and disadvantages. The obvious advantage is that it is convenient to assemble it, as a designer in childhood. But the main drawback - it is strong only in two directions, but weak when twisting. So, it is necessary to take into account this weakness and calculate what torque can be transmitted from the pulleys to the frame, and compensate it with the help of additional jumpers. Cutting: You can cut the corner use a hacksaw, but an angle grinder with a cutting disc will make things faster. After cutting all the elements, I would recommend polishing all their sharp edges so as not to cut themselves during assembly. Holes can be drilled using a conventional drill and coolant.
Main movieThe main roller is the most important part of the project, as it receives torque from the motor and transfers it to the belt. I used an old bushing to fasten it, but I recommend using a bearing instead. The bushings do their job, but they constantly overheat and require regular lubrication. Moreover, they can spread dirty grease, which is annoying during work. Shaft: There are threads on the sides of the shaft with different directions so that the fixing bolts do not twist while rotating. If you cut one side with the thread, as I did, leave the one that goes counter-clockwise, otherwise you'll have to make a safety bolt (I'll describe how to do it later) and a cotter pin. The main pulley will be put on the cut edge. Pulley: Continuing the theme of reuse, I found an old pulley from another project. Unfortunately, I prepared him under the threaded pin, on which he was supposed to hold, but, in fact, this is not a problem.In this pulley I made a rectangular cut. Then, using an angle grinder, I cut a groove at the end of the shaft. I placed the key in the hole formed by the shaft slot and the rectangular cutout of the pulley, I securely fixed them relative to each other.
Making the rollers for the grinding machineI made rollers from several pieces of hard wood 2.5 cm thick, but you can use MDF, plywood or other material.When laying the layers you need to make the fibers perpendicular, this will give the rollers extra strength and layers will not crack. It is necessary to make tr roller: main roller, upper roller and tension roller. The main roller is made of two 13 x 13 cm pieces 2.5 cm thick. The top and tension rollers are made of two pieces of wood measuring 10 x 10 cm. Process: Start by gluing pairs of 13 cm and 10 cm pieces of wood, clamping them with clamps. After the glue dries, cut the corners with a miter saw, then find the center of each part. Secure them in the lathe and process until their dimensions become 5 x 10 cm and 5 x 8 cm. Upper and tension rollers: Next, you need to install the bearings in the rollers 5 x 8 cm in size. Choose a crown or first drill, and in the center drill a recess to the width of the bearing.The inner ring of the bearing should rotate freely, so you need to drill a hole that passes through the roller through the inner ring of the bearing. This will allow the bolt to go through with a minimum hole. Main movie: This part is done a little differently. There are no bearings on it, however if the shaft leaves the roller less than 5 cm, it will be necessary to grind the roller in width. Measure the diameter of the shaft and in the center of the roller you need to drill the same hole. Try to insert the shaft, it must hold tight, otherwise the roller will shake.
Bolt the rollersNext, fasten the two halves of the rollers with bolts, do not rely only on glue. Remember that the bolt heads must be drowned in the tree as the roller spins in close proximity to the frame.
The tension leverThe lever is made of a metal strip of 10 x 30 x 200 mm in size with rounded edges. It is necessary to drill quite large holes in it, so I recommend using a drilling machine and a lot of lubrication for this. Just need 4 holes. The first is at the point of rotation. It is not in the center of the plank, but 8 cm from its edge. The second hole will be located on the edge closest to the point of rotation. It will serve to mount the spring. Drill two additional holes at the opposite end, approximately 5 cm apart. They should be slightly wider in diameter, as they will be used for adjustment, which I will discuss next. When all the holes are made, you can fix the shoulder on the vertical corner between the upper roller and the base. The end on which the spring will be mounted is directed towards the main roller. It should rotate freely, so I recommend using two nuts for fastening, the main twisting is not fully completed,and using the second as a lock nut.
Installing rollersThe upper roller is fixed statically and must be clearly aligned in the same plane with the tension roller and the main roller. You can do everything by sight, but I recommend to check everything well by level. To align the roller, you can add a washer, or, if there is not enough of it, a bolt. They are inserted between the frame and the roller. You do not need to completely install the tension roller. We still need to make a stabilizing device.
Ribbon StabilizationRolling debris or uneven surface can lead to the fact that during the work the abrasive belt will gradually come down from them. The stabilizing device is a device on a tension roller, which allows it to be at an angle that keeps the abrasive tape in the center. Its device is much simpler than it looks, and consists of a fixing bolt, a little free play of the tension roller and a control bolt. Drilling holes in bolts: For this purpose I manufactured device, in the form of a wedge-shaped notch in the board, which will help at the time of drilling to hold the bolt in place. You can do this manually, too, but I do not recommend it.
Fixing boltThe fixing bolt is a simple bolt with a hole drilled in it, and which is installed on the bar through a wide hole,which is closer to the point of rotation of the lever. Since it is located between the lever and the roller, its head must be grinded so that the roller does not cling to it. The bolt must be fixed as shown in the figure.
The bolt on which the roller is attachedIt needs to be loosened a bit so that the tensioning roller has a slight play. But so that it does not unwind, you need to make a crown nut. To do this, you just need to make cuts on the edges of a normal nut, so that it looks like a crown. There will be two drilled holes in the bolt itself: one for the adjusting bolt, and it will be aligned with the fixing bolt hole, and the other for fixing the castle nut with a cotter pin. Adjustment bolt: After the tensioning roller is in place, you can install the adjustment bolt, which will pass through the holes of the fixing bolt and the bolt on which the tensioning roller rotates. The system works when you tighten the adjusting bolt, forcing the axis of rotation of the tension roller to shift the angle of rotation outward, thus forcing the tape to move closer to the mechanism. A spring from the other end of the lever adjusts the tension in the opposite direction.I recommend fixing the adjusting bolt with a lock nut, since vibrations can weaken it. Note: You can add a spring on the back of the tensioning pulley, but I haven’t found any reason why it is worth doing. A small advantage is that in this way the roller will have a smaller backlash. But I’ll add that I didn’t do this, and I didn’t have any problems.
Completing the work on making the machine yourselfWhen done, you need to check all the bolts again and make sure that the stabilization mechanism is assembled correctly. Then you need to turn on the device for the first time, which can be scary. As if driving a car where the steering wheel and transmission do not work.I recommend switching the motor on and off for a very short time so that the machine does not rotate at full power. In fact, for me, the most difficult part was the adjustment of the spring. If it is too tight, the tape will not be able to rotate ... Too weak - and it can not be held, it flies, which in itself is dangerous. Done! That's it. You should have a decent average-capacity belt grinder that can be converted into a more powerful one if you wish. I hope you enjoyed this master class. Thank you for your attention.
Date: 09.10.2018, 08:52 / Views: 71565
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