Obtaining a hole by the method of drilling, the walls of which would be perfectly smooth, is obtained not in every case, even if high-quality drills and drills are used. In addition, the diameter of the hole may differ from the required by several tenths of a millimeter. For gaps to be perfect, you need a manual sweep. These are metal cutting tools specially designed for finishing holes after drilling and countersinking operations. Let's look at what this tool is, how it works, why it is needed and how to apply it.
Characteristic
Sweep is a cutting tool for metal processing. By processing the hole with this device, you can increase its diameter, as well as significantly improve the surface cleanliness and size accuracy. Reamers are used for both finishing and preprocessing. There is a standard according to which manual scanning is regulated - GOST 7722-77. Hand tools are considered to be intended for processing holes with a diameter in the range from 3 to 60 mm (pitch - 1 mm).
Using these tools, you can get sizes whose accuracy will correspond to the second and third class. As for the surface cleanliness, it can be from Rz 10 to Rz 6.3. Drilling of such purity is impossible to achieve.
Sweep principle
Using a tool for processing holes, it is possible to achieve high accuracy and surface quality - this is already mentioned above. Manual sweep works on a small scale. It is possible to correct the holes with such accuracy because the tool is equipped with several cutting edges. So, a manual scan - depending on the type - can have from 4 to 14 cutting edges. It is due to this that the smallest bites are removed.
The tool works as follows. The reamer must be inserted into the hole, then, if it is manual, put on a special knob and rotate the tool with it. The device will work not only with rotational movements, but also while moving down or up along the axis. The tool is capable of removing thin layers of metal - from a few tenths to hundredths of a millimeter.
It is possible to process in this way not only traditional cylindrical openings, but also conic. For this, a conical scan is used. There are several types of this cutting tool. In the article we will consider each of these types.
What does a scan look like?
And the device looks as follows. This is a cylindrical or conical rod, which has longitudinal grooves on the working part. The other part is smooth and can be equipped at the end with a square or tapered shank.
The working side of the tool is represented by several departments. The front is conical and short. Then comes the direct cutting, after - the guide part and, finally, the rear worker.
This is what the scan looks like. The tool, despite such a large number of working parts, directly cuts metal only with the receiving or working part. The short backside is called gauge. Between the cutting teeth, grooves form. They are designed for chip evacuation during tool operation. Cutting edges are located around the entire circumference of the shaft.
Classification
As you know, reamers are designed for finishing finishing holes. In direct proportion to technological requirements, using these tools get holes in different tolerance ranges - from the fourth grade to the first. The accuracy of its operation depends on the design, as well as on the quality of the tool. For different holes, different manual sweeps are used - we will consider the main types.
As for the characteristics of the tool, here is not the only factor that plays a role:
- Cutting modes.
- Values for deployment allowances.
- Tool sharpening level.
- The geometry of the cutting edge, as well as many other factors.
Reamers are distinguished by the type of hole for which they are intended. The shape of the cutting teeth and the material to be processed are also important.
In operation, to carry out the main part of locksmith operations, the following are used: a cylindrical scan, adjustable tools, and conical ones. Along with manual ones, there are also machine ones. These tools can be of different types. There are cylindrical, conical, with interchangeable teeth, with carbide cutting inserts.
The conical reamer includes a large group of tools - for conical pins, for machining conical threads, under Morse cone, under metric cone. Particularly widely used in plumbing is a cylindrical fine-grained tool.
Cylindrical
Such a reamer is designed to handle cylindrical holes.
Manual sweep can be used both with a winch and with an electric drill at low speeds. This tool can be performed in one piece or with the ability to adjust the working diameter.
Conical
Such a tool is designed to work with conical shaped holes.
They can also be used for traditional cylindrical holes.
Draft, intermediate, finishing
If you need to expand the size of the hole in serious limits, then you can not do without a set of tools of different purity. Conical development, like all others, is divided into draft, intermediate, and finishing.
The first tool is distinguished by teeth, steps located along the entire line. Such a tool works as follows. Narrow chips are cut using the cutting edge of each step. Moreover, if the hole was cylindrical, then after such a treatment it turns into a stepped conical.
Intermediate sweeps for metal can cut chips of significantly smaller thickness. The cutting part is distinguished by special channels for chip separation. Fine tools cut metal all over the work surface. Thus, a cylindrical or conical hole of the desired size is formed. As you can see, the principle of operation is quite simple.
Adjustable
A modern cutting tool of this type can be of various designs. In the market you can find expandable and sliding models. Both types work on the basis of one principle - when moving up or down, the diameter of the hole can decrease or increase. The adjustable sweep of these two types differs in how the tightening is carried out, as well as in the size range.
So, in the expandable design there is an upper and lower nut. The size can be changed in the range from 0.25 to 3 millimeters. In sliding reamers, the diameter changes by tightening the screw. The latter forces a special ball to move in the housing, which unclenches the cutting parts. Adjustable adjustable sweep is considered more accurate, and you can maximize the diameter from 0.15 to 0.5 millimeters.
As for the latter type, the tool is structurally similar to all other sweeps. It is a body made of inexpensive steel and insert cutting parts. Knives are made more often in the form of thin plates. The material used is tool steel. The plates are removable, sharpenable and replaceable.
Such a scan for metal makes it possible to change the diameter of the hole by tenths and hundredths of a millimeter. Unlike whole, they are more economical. In case of wear, the knives can be easily replaced.
What do you need to know about hole deployment?
The hole boring process is best done using two classes of tool - rough reamer and finish. The former are often made from old and worn materials. Before deploying the hole, its end part is grinded. This is done so that the scan can work effectively with each of its teeth. This is true for parts made of cast iron. If you neglect such pre-processing, there is a risk of blunting the scan.
In the process of working with a scan, it is better not to rush once again. The feed must be uniform. The slower the tool feeds into the hole, the better the final result. The deployment process does not include work at high speeds, as is the case with a drill. Experienced locksmiths recommend setting aside an electric drill, and instead take a handle. In this case, the control over the process will be much higher.