The easiest way to mark the center holes is with a compass, one of the legs of which is bent inward. Having spread the legs of the compass so that the distance between them is approximately equal to the radius of the marked workpiece, and taking the compass right hand, press the end of the bent leg with the thumb of the left hand to the side surface of the part (Fig. 43, a) fixed in a vice. After that, with a sharp leg of the compass, four risks are applied to the end of the part (Fig. 43, b, c)
If the distance between the legs of the compass was set to be greater than the radius of the part, these risks will have the form shown in Fig. 43b; if it was less than the radius of the part, the risks will have the form shown in Fig. 43, c. The center of the detail in both cases lies within these marks and can be easily marked by eye.
Rice. 43. Marking the center hole with a compass (a) and the position of the resulting risks (b, c)
The marking of workpieces from precision rolled products, especially if the machining allowance is small, as well as machined parts in which for some reason there are no center holes, should be done using a marking square (Fig. 44, a). Pins 1 and 2 are pressed into the short shelf of this square at equal distances from its edge AA. Having imposed such a square on the end of the part (Fig. 44, b), it is carried out at the last risk. Then the square is rotated to an arbitrary angle and a second risk is drawn (Fig. 44, c). The intersection of the marks will determine the center of the workpiece or part.
Rice. 44. Marking square (a) and marking (b, c) center holes using a square
Punching center holes. After marking the center holes, they are punched (Fig. 45, a). The error made in this case can be eliminated by shifting the marked center in the required direction, as shown in Fig. 45, b.
Rice. 45. Punching a center hole
Centering tools. The center holes are drilled with a twist drill (Fig. 46, a), the diameter of which is equal to the diameter of the cylindrical part of the center hole. The conical part of the center hole, drilled with a drill with a diameter of up to 1.5 mm, is formed by a countersink (Fig. 46, b). With a diameter of the cylindrical part of the hole up to 6 mm, a countersink is used to process the cone, shown in Fig. 46, c. The countersink shown in Fig. 46, g, are used to obtain a center hole with a safety cone.
Rice. 46. Centering tools
A center hole without a safety taper can be drilled much faster using the combination center drill shown in fig. 46, e, and a hole with a safety cone - a drill, shown in fig. 46, e.
Drilling center holes. Center holes are drilled in small workpieces made of rolled material or previously turned material without marking. The workpiece is fixed in a self-centering chuck (Fig. 47, a). A drilling chuck with a centering tool is inserted into the tailstock quill. Having drilled a center hole in one end of the workpiece, turn the workpiece over and drill a second hole.
Rice. 47. Drilling center holes
Marked and cored blanks are centered like this. Instead of the front center, a chuck with a centering tool is inserted into the machine spindle. Having installed the workpiece, as shown in Fig. 47, b, hold it with the left hand behind side surface(and even better for a clamp fixed in the middle of the part). Having started the machine and turning the handwheel of the tailstock with the right hand, the workpiece is fed to the rotating centering tool. The second center hole is drilled in the same way.
At many factories, centering of workpieces is carried out in procurement workshops (at warehouses) on special centering machines.
It is customary to understand the sequence of operations for attaching the hinge to the facade (door) of furniture by “hinge attachment”. As a rule, we are talking about the so-called. four-hinged hinges, as the most common in the production of cabinet furniture. To fasten a four-hinged hinge to the facade, it is necessary to make a special seat - blind hole specified diameter and depth. How to plant correctly furniture hinge using the minimum set hand tool will be discussed in this article.
Required tool:
- Construction corner (gon).
- Pencil.
- Kerner (optional).
- Drill for metal with a diameter of 2 mm (optional).
- Faustner drill with a diameter of 35 mm (or 26 mm for reduced loops).
- Electric drill.
The Faustner drill (mill) is a very common tool used to make blind (not through) holes in soft materials. When buying a Faustner drill for adding furniture hinges, you need to pay attention to several points. First, the needle (central sharp tip) of the drill should be well centered (not have noticeable beats). Secondly, the drill must have carbide (they are often called victorious) cutters, otherwise it will become dull very quickly. The length of the centering needle is very important parameter. If the length of the needle is too large, then there is a risk of drilling through the facade. If the length of the needle is insufficient, then the drill (when drilling hand drill by hand) will lead to the side. As a rule, the length of the needle of a new drill has to be reduced (grinded) by about 0.5 mm. Professional (machine) Faustner drills have a reduced needle length or do not have one at all, since they are designed for special filler machines or machining centers, where accuracy is ensured by other means. It is strongly recommended that before drilling into a façade, a test hole be made in a similar material of the same thickness.
Preparation.
The surface of the workbench on which the additive will be performed must be flat, clean, and non-slip. Under the facade, you can put, for example, a sheet of thin rubber, a piece of foamed polyethylene (a type of insulation) or several layers of packaging stretch film. It will not be superfluous to fix the facade with clamps. Be mindful of your personal safety, use protective goggles when drilling.
Hole marking.
Markup is a responsible operation. The accuracy of the installation of the loop and the correct operation of it depend on its accuracy. The figure below shows the dimensions for marking. Special attention should be given an indent of 21-22 mm from the working (along which the hinges are attached) side of the facade. The other margin (right/left in the figure) is not as important in terms of accuracy. The main thing is that the first and last hinges of the facade are located at distances from 70 to 150 mm from the sides of the facade adjacent to the working side. The total number of hinges on the facade can be two or more, depending on the size and weight of the facade.
Indents for marking.
Indent 21 mm.
Indent 100 mm.
Drilling center punching.
After punching, everything is ready for drilling.
Drilling a hole for a hinge.
Before drilling, it is recommended to punch the center of the drilling. Drilling must be performed at a speed of about 1500 rpm, too high speeds will lead to burning of the facade material, the cutter will quickly become dull due to overheating. When drilling with a hand drill, it is recommended to perform light circular movements (describing a cone with a tip on the drill needle) of small amplitude, this will increase the efficiency of material sampling. Since the depth of drilling, by and large, is controlled by eye, from time to time it is necessary to stop drilling and measure the depth (the easiest way to do this is using the existing loop). As a rule, a depth of 12 mm is sufficient.
Drill with Faustner bitdiameter 35 mm.
Drilling completed.
Fastening hinges on the facade.
This is the simplest operation. To perform it, you need to insert a loop into drilled hole, align the platform of the hinge bowl with a square, mark the attachment points with a pencil and, after preliminary punching and / or drilling (with a drill with a diameter of about 2 mm), fasten the hinge with two self-tapping screws 3.5x16 mm (the length of the self-tapping screws depends on the thickness of the facade). A slight inaccuracy of the installation (up to 1 mm) is not necessary to correct. With some experience, the loop can be screwed without marking, punching and drilling, but simply according to the attached square.
Alignment with a square and designation of the mounting holes of the hinge with a pencil.
Hole punching. Drilling has not been performed.
We examined the principle of manual stitching of a loop, which can be performed even at home. However, it is recommended that loops be added on specialized equipment (even home-made), the most affordable option- normalvertical type initial price category . This will significantly increase labor productivity, reduce the risk of damage to facades.
Drilling methods
There are the following drilling methods: by marking, by template, by jig. Depending on the complexity of the part, the holes in it are drilled directly on the machine or in special devices, having previously secured the part with clamps or clamps.
Hole marking
In order to determine the location of the holes in the part, markup is carried out, guided by the drawing. Starting the markup, first select such points or surfaces on the part, the position of which is sufficiently defined and will not be changed during further processing. From these points or surfaces, the dimensions are measured when marking. Distinguish the following types markups:
1. Marking with a marking tool, i.e.
a) using a ruler and a compass;
b) with the help of a thickness gauge.
In this case, a steel ruler is used to mark the holes, with a simple pencil and a drawing scriber (Fig. 48).
2. Template markup mainly used for drilling a large number homogeneous details.
The marking template must have contours that exactly match the parts, and the holes located in it must indicate the centers of the holes to be drilled.
Templates are made from sheet metal thickness 1.5 - 2.5 mm or from plywood with a thickness of 3 - 5 mm. The template in production replaces the drawing and at the same time serves as a fixture.
Drilling templates used in aircraft construction are called "SHOCK" (trimming templates and jig) and serve to mark the contour of the part and to directly drill holes in the part (Fig. 49).
On the template, an indication is applied to install the template on the parts. In order to extend the life of the template, it is necessary to put metal washers over the holes (Fig. 50).
If there is no washer on the template, it is necessary to drilling machine install the conductor sleeve (Fig. 51). In this case, the cutting edges of the drill will not spoil the surface of the holes in the templates.
Holes for drill bushings on all templates are made the same size. Inner diameter The drill bushing is different, depending on the size of the drill.
Markup techniques
1) Mark the holes with a ruler and pencil, using the following techniques:
a) carefully analyze the drawing and look at the processed workpiece, check the cleanliness and correctness of the processing of the edges from which you need to set the size;
b) using a thickness gauge, set aside the size from the edge of the part to the axis of the holes (Fig. 52);
c) draw a straight line with a steel ruler and a pencil (Fig. 53);
d) mark the axes of the holes on this line using a compass, square and pencils (Fig. 54);
e) outlines from the obtained centers of the circle of the required diameter (Fig. 55).
2. Mark the holes with the template in the following order:
a) apply the template to the part, aligning the contours of the part and the template;
b) mark the part along the holes in the template (Fig. 56), using a scriber.
1. Set the outline on the edge of the workpiece and fix it at a distance equal to the distance to the bend or cut.
2. Draw a line from the edge of the sheet (draw the outline parallel to the plane of the sheet) (Fig. 24).
Marking and punching centers before drilling holes
1. Mark the centers of the holes of the upper seam in a checkerboard pattern according to drawing 1 (Fig. 25).
2. Punch the intersection points (Fig. 26).
The centers of the holes are punched before drilling sheets, parts and assemblies.
Marking with a thickness gauge
1. Mark a square on the end and on the side surface of a round steel billet (Fig. 27).
2. Place the steel bead on the prism.
3. Mark the axes:
1) install the thickness gauge arbitrarily, fix it in draw on the end of the roller short line(Fig. 28);
2) turn the roller 180 ° and, without moving the scriber, draw a short line parallel to the first one on the end of the roller
3) halve the distance between two parallel lines, set the thickness gauge along the marked middle and draw an center line through the middle (Fig. 30);
4) turn the roller by 90 °, align the vertical position with a square and, without moving the thickness gauge scribers after drawing the first center line, draw the second center line
rice. 30. (Fig. 31 and 32);
5) mark the center and outline a circle with a diameter of 11 mm (Fig. 33).
1. Mark the sides of the square at the end and on the side surfaces (Fig. 34 and 35).
4. Mark the length of the square (Fig. 36).
e) Marking when assembling units and installing them on an aircraft
Marking is done not only in the manufacture of parts, applying the outlines (contours) of parts to the material, marking the places of holes, etc., but also when installing parts and assemblies in place during their assembly.
To determine the location of parts and assemblies on the machine, it is necessary to measure and mark these parts and assemblies on the machine itself in accordance with the dimensions indicated in the drawing.
A. Marking the position of the clamp on the side member
It is required to install clamp A on the side member B. According to the drawing, the middle of the clamp should be at a distance
175 mm from axle vertical rack in the fuselage; clamp length - 36 mm, pipe diameter B is 20 mm (Fig. 37).
1. Determine the distance from the end of the collar closest to pipe B to the nearest point on that pipe. This distance must be less than 175 mm by half the length of the clamp and half the diameter of the pipe, i.e. less by
36/2 + 20/2 = 56/2 = 28 mm.
Then the distance from the end of the clamp to pipe B will be 175 - 28 = 147 mm.
2. Attach a meter to the side member so that its beginning rests against pipe B.
3. Make a mark with a pencil on the side member against the division of 147 mm.
4. Put a clamp on the side member so that its end, directed towards the pipe B, coincides with the mark.
In this case, the middle of the clamp A should be at a distance of 175 mm from the axis of the pipe B.
B, Marking the position of the clamp on the side member using a special template
1. Attach the cutout of the ruler of template A to the post and press the bracket of template B to the side member (Fig. 38).
2. Draw a line along the edge of the bracket to determine the location of the clamp on the side member.
B. Marking the axis of the fuselage on its skin
Draw the longitudinal axis of the fuselage on its skin. According to the drawing, the upper side of the spar in the area from the first to the third frame is parallel to the fuselage axis and is located at a distance of 490 mm from it (Fig. 39).
a) Place the heel of the square with a long shelf on the upper side of the spar so that the shelf of the square lies on outside plywood sheathing, closer to the first frame.
b) Draw a line along the pole with a pencil.
c) Draw a line in the same way at the third frame.
d) Measure along the drawn lines from the upper side of the upper side member 490 mm each and make marks.
e) Draw a line through these marks, which will be the axis of the fuselage (the fuselage tapers towards the tail along a curve and therefore
The center line can only be drawn with three help of a flexible metal ruler or a flexible wooden ruler).
The first worker applies one end of the ruler to the mark at the first frame, the second worker, located at the tail, firmly presses the ruler to the fuselage, and the third worker monitors
so that the ruler coincides with the second mark and instructs the second worker to raise or lower the end of the ruler. Supporting the ruler with his left hand, the third worker draws an axis with a pencil.
f) Mark holes or necessary points on the squares; squares have holes or cutouts on the shelf to mark the necessary points.
Basic markup rules
1. When marking parts and assemblies during assembly, remember that marking is always carried out from such points and surfaces, the position of which is quite definite on the plane. The main base for marking on an aircraft is the longitudinal axis of the fuselage or points and lines associated with it by certain dimensions.
2. When starting to markup, draw up a plan for yourself, that is, establish in what sequence to markup and with what tool.
3. When drawing lines, hold the pencil or scriber a little obliquely so that the line closely adjoins the ruler or square, which must be firmly supported with the left hand.
4. For marking, use a simple, not chemical pencil. When applying scratches with a scriber, you can scratch the material, which will degrade the quality of the product. So, for example, scratches on duralumin, which violate the integrity of the outer layer of the metal, reduce its strength and resistance to corrosion. Chemical pencil spoils duralumin, causing corrosion.
5. Remember that markup is much easier and faster if you use templates.
6. To speed up the marking of long lines, when great accuracy is not required, instead of drawing them, take a hinted thin cord and beat off the lines with it.
How to mark alignment steel chimney when passing through the ceiling and roof?
To answer exhaustively, it is advisable to know at what stage you are:
- the place for the heat generator is prepared, and you only need to lay / mount the chimney,
- build a house and select the exact place for the stove, bypassing the beams and rafters.
Anyway the right tool for similar works there will be a simple construction plumb line. Even the highest quality rack levels and rules do not allow you to make accurate vertical markings over long distances. In addition, their "bubbles" work only in one plane, and we need a vertical axis in all directions.
If the marking is carried out from the bottom up “from the furnace”, then you need to do the following:
- Mark the center (axis) of the chimney on the floor or on another stable plane. It should be a crosshair of lines.
- Stretch the plumb line from ceiling to floor. It is advisable to work with an assistant. He presses the thread to the ceiling with his hands, and you, looking at the center of the plumb line, command the movements until the top of the cone coincides with the crosshair.
The tip of the plumb line should be as close to the floor as possible, but touching is not allowed. If the plumb line swings for a long time, then the worker below can gently stop it with his fingers
We put a cross on the crate or on the very roofing material(depending on where the markup went). Now you can create the outline of the passage and do the cutting
This way you can find the axis, even if the floor has already mounted a passage unit. Please note that the axis point is also transferred with a plumb line in the opposite direction: from the roof to the ceiling (and then to the furnace).
An excellent tool for determining vertical axes is a laser plotter with a plumb line function. Such devices automatically align and give an exceptionally clear axis above and below themselves (zenith and nadir). The builder can be installed on the stove, and the beam, for example, can be sent through the hole to the very roof. And you can place it on the ceiling and let coaxial rays up and down.
Even household models will perfectly cope with the task. No markup assistant needed
And there is another way of marking, but it will not give an axis, but a contour. Knowing the place where the pipe passes through the ceiling, as well as being able to temporarily assemble the chimney, you can bring it to the roof using any levels for orientation in space. Then the top of the pipe is wrapped with a sheet of cardboard. This wrapper (with sliding along the pipe) is lifted to the roof slope and an oblique cut is made on the cardboard corresponding to the angle of the roof in this place. Then the cardboard imitation of the pipe is again brought to the slope and the junction is circled with a marker.
So get very fine hole(its shape, by the way, will resemble an ellipse), but do not forget that when passing building structures it is necessary to create technological gaps.