Hole marking. When marking hollow parts (Fig. 81), a so-called center bar made of wood is hammered into them, and then a metal bar made of brass or lead is stuffed onto it to support the leg of the compass. If the plank is made of hard wood, then you can skip the metal plank. Further marking is carried out in the usual way.
Figure: 81. Techniques for marking holes on workpieces
For marking even small batches of complex products that require a significant investment of time, it is advisable to use templates (Fig. 82). The template is placed on the workpiece to be marked out (part) and outlined with a scribe.
Figure: 82. Template markup
The advantage of this method is that the marking work, which can take a lot of time, is done only once during the production of the template. All subsequent marking operations are only copying the outline of the template, they can be performed accurately and without difficulty. Layout templates can also be used for post-processing control.
Sample layout. It is used in cases of wear or breakdown of a part and in the absence of a drawing for making a new one. In such cases, the broken part is the reference. If the part is flat, then after thorough cleaning it is applied to the workpiece and marking lines are drawn around it.
In cases where it is impossible to impose a sample on the workpiece, it is installed side by side and all dimensions are transferred from it to the workpiece with a thickness gauge. When taking measurements from the sample, the wear of the old part should be taken into account, and also check if it is damaged, warped, not broken off protrusions, etc.
In-place markup.Produced in cases where the nature of the connections requires the assembly of parts on site. To do this, one of the parts is marked out, holes are drilled in it; in the second part, the holes are drilled after the first is superimposed on it, which is, as it were, a template in relation to the second.
Spatial markup.Marking several surfaces of the part located in different planes and under different anglesproduced from one base (surface or line) on the workpiece is called spatial marking.
Figure: 83. Methods of marking (spatial) keyway
For example, the spatial marking of the keyway on the roller must be performed in the following order (Fig. 83):
1. Examine the drawing.
2. Check the workpiece.
3. Clean the markings on the roller.
4. Paint the end of the roller and part of the side surface on which the risks will be drawn with vitriol.
5. Find the center at the end using the center finder.
6. Place the roller on the prism and check that it is horizontal.
7. Apply a horizontal line through the center to the end of the roller with a thickness gauge.
8. Turn the roller 90 ° and align the drawn line with a square.
9. Apply a horizontal line to the end of the roller with a thickness gauge.
10. Draw a line with a thickness gauge on the side of the roller.
11. Draw two lines on the side surface corresponding to the width of the keyway, and on the end face to approximately the depth of the groove.
12. Rotate the roller with the key notches up and draw a line for the depth of the keyway on the end face.
13. Beam the contours of the keyway.
Marriage when marking.The most common types of marriage during marking are:
1) inconsistency of the dimensions of the marked workpiece with the drawing data, which occurs due to the inattention of the marketer or inaccuracy of the marking tool;
2) inaccuracy in setting the dimensions. The reason for such a marriage is the inattention or inexperience of the scribe;
3) careless installation of the part on the plate as a result of inaccurate plate alignment when installing the part. Displacement of the part during layout, which gives distortions.
The main condition for high-quality marking is a careful attitude to work, as well as the use of serviceable tools.
Safety precautions.When marking, it is necessary to securely install the plate, after working on the planers of the planes, put on protective plugs, use serviceable devices (jacks, marking boxes, squares, etc.).
1. Place the outline on the edge of the workpiece and fix it at a distance equal to the distance to the fold or cut.
2. Draw a line from the edge of the sheet (the outline should be parallel to the plane of the sheet) (Fig. 24).
Marking and punching centers before drilling holes
1. Mark out the centers of the holes of the upper seam in a checkerboard pattern according to drawing 1 (fig. 25).
2. Draw the intersection points (fig. 26).
Hole centers are punched out before drilling sheets, parts and assemblies.
Marking with a planer
1. Mark a square at the end and on the side of the round steel workpiece (fig. 27).
2. Place the steel roller on the prism.
3. Mark the axes:
1) set arbitrarily the planer scribe, fix it in draw on the end of the roller short line (fig. 28);
2) turn the roller 180 ° and, without moving the scribe, draw a short line parallel to the first one on the end of the roller
3) halve the distance between the two parallel lines, set the planer scribe along the marked middle and draw a center line through the middle (Fig. 30);
4) turn the roller 90 °, align the vertical position with a square and, without moving the planer scraper after drawing the first center line, draw the second center line
fig. 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
The marking is done not only during the manufacture of parts, drawing outlines (contours) of parts on 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, you have 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 the clamp A on the side member B. According to the drawing, the middle of the clamp should be at a distance
175 mm from axis 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 clamp, located closer to the pipe B, to the nearest point on this pipe. This distance should 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 \u003d 56/2 \u003d 28 mm.
Then the distance from the end of the clamp to the pipe B will be 175 - 28 \u003d 147 mm.
2. Apply the meter to the spar so that its beginning rests against pipe B.
3. Make a pencil mark on the side member against 147 mm division.
4. Put the clamp on the side member so that its end, directed towards 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 template A to the stand and press the clamp of the template B to the side member (Fig. 38).
2. Draw a notch along the edge of the bracket to locate the clamp on the side member.
B. Marking of the fuselage axis 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 section 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 elbow with a long flange on the upper side of the side member so that the flange of the elbow lies on outside plywood sheathing, closer to the first frame.
b) Draw a line along the fold 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 at 490 mm and mark.
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 centerline can only be drawn with three using 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 against the fuselage, and the third worker monitors
so that the ruler aligns 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 required points by angles; squares have holes or cutouts on the shelf to mark the required points.
Basic markup rules
1. When marking parts and assemblies during assembly, remember that the marking is always carried out from such points and surfaces, the position of which is quite definite on the airplane. The main base for aircraft markings is the longitudinal axis of the fuselage or points and lines associated with it with certain dimensions.
2. Starting to markup, make a plan for yourself, that is, establish in what sequence to markup and with what tool.
3. When drawing lines, hold the pencil or scribe slightly obliquely so that the line is close to the ruler or square, which must be firmly supported with your left hand.
4. Use a simple pencil for marking, not a chemical pencil. When drawing with a scribe, the material may be scratched, 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. The chemical pencil spoils the duralumin, causing corrosion.
5. Remember that layout is much easier and faster if you use templates.
6. To speed up the marking of long lines, when great precision is not required, instead of drawing them, take a deliberate thin line and beat off the lines with it.
Drilling methods
Distinguish following ways drilling: by marking, by template, by conductor. Depending on the complexity of the part, holes are drilled in it 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 performed, guided by the drawing. Starting to markup, first select such points or surfaces on the part, the position of which is sufficiently defined and at further processing will not be changed. Dimensions are measured from these points or surfaces when marking. There are the following types of markings:
1. Marking with a marking tool, i.e.
a) using a ruler and compasses;
b) using a planer.
In this case, a steel ruler, a simple pencil and a drawing scribe are used to mark the holes (Fig. 48).
2. Template markup mainly used for drilling a large number homogeneous parts.
The layout template must have contours that match the details exactly, and the holes 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 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" (cutting templates and a jig) and are used to mark the contour of the part and for direct drilling of 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 service 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 jig bush (Fig. 51). In this case, the cutting edges of the drill will not spoil the surfaces of the holes in the templates.
Holes for jig bushings on all templates are made of 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 disassemble the drawing and look at the processed workpiece, check the cleanliness and correctness of the processing of the edges, from which you need to postpone the size;
b) using a thickness gauge, set 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, a square and pencils (Fig. 54);
e) outline from the obtained centers of the circle of the required diameter (Fig. 55).
2. Mark the holes using the template in the following order:
a) place the template on 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 scribe.
Under the "hinge additive" it is customary to understand the sequence of operations for attaching the hinge to the facade (door) of the furniture. Usually, it comes about the so-called four-hinge hinges, as the most common in the production of cabinet furniture. To fasten the four-hinge hinge to the facade, it is necessary to make a special seat - a blind hole of a certain diameter and depth. How to properly attach a furniture hinge using minimum set hand tool will be discussed in this article.
Required tool:
- Construction corner (square).
- Pencil.
- Kerner (optional).
- Drill bit 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 (cutter) is a very common equipment used to make blind (not through) holes in soft materials... When buying a Faustner drill, for an additive furniture hinges, you need to pay attention to several points. First, the needle (center sharp tip) of the drill must be well centered (no noticeable runout). Secondly, the drill must have carbide (they are often called victorious) cutters, otherwise it will become blunt very quickly. Centering needle length - very important parameter... If the length of the needle is too long, 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. Typically, the needle length of a new drill has to be reduced (ground) 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 welding machines or machining centers, where accuracy is ensured by other means. It is highly recommended that before drilling in the facade, make a trial drilling in similar material the same thickness.
Training.
The workbench surface on which the additive will be applied must be flat, clean and non-slip. For example, a sheet of thin rubber, a piece of expanded polyethylene (a type of insulation) or several layers of packaging stretch film can be placed under the facade. It will not be superfluous to fix the facade with clamps. Do not forget about personal safety, use safety glasses when drilling.
Hole marking.
Marking is a responsible operation. The accuracy of the loop installation and the correctness of its operation depend on its accuracy. The figure below shows the dimensions for striping. 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 indentation (right / left in the figure) is not so important in terms of accuracy. The main thing is that the first and last loops of the facade are located at a distance of 70 to 150 mm from the sides of the facade adjacent to the working side. The total number of loops on the facade can be two or more, depending on the size and weight of the facade.
Indentation for marking.
Indent 21 mm.
Indent 100 mm.
Center punching.
After punching, everything is ready for drilling.
Drilling a hole for the hinge.
Before drilling, it is recommended to turn the drilling center. It is necessary to drill 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 drilling depth is by and large, is monitored by eye, then from time to time it is necessary to stop drilling and measure the depth (the easiest way to do this is on the existing loop). As a rule, a depth of 12 mm is sufficient.
Drill with a Faustner drilldiameter 35 mm.
Drilling completed.
Fastening the hinges to the facade.
This is the simplest operation. To complete it, you need to insert a loop into drilled hole, align the platform of the hinge bowl using 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), screw the hinge with two 3.5x16 mm self-tapping screws (the length of the screws depends on the thickness of the facade). It is not necessary to correct a slight inaccuracy of the installation (up to 1 mm). With some experience, the loop can be screwed on without marking, punching and drilling, but simply using the attached square.
Alignment with a square and mark the hinge mounting holes with a pencil.
Punching holes. No drilling was performed.
We considered the principle of manual looping, which can be done even at home. However, it is recommended to add the loops using specialized equipment (even if homemade), the most affordable option - normalvertical type initial price category ... This will significantly increase labor productivity and reduce the risks of damage to facades.
How to mark the alignment of a steel chimney when passing through the ceiling and roof?
To answer comprehensively, it is advisable to know what stage you are in:
- the place for the heat generator is prepared, and you only need to conduct / install the chimney,
- build a house and choose the exact place for the stove, bypassing beams and rafters.
Anyway the right tool for such work, there will be a simple construction plumb line. Even the highest quality slatted levels and rules do not allow for 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 oven", then you need to do the following:
We put a cross on the crate or on the very roofing material (depends on where the markup ended up). Now you can create a path outline and start cutting
In this way, the axis can be found even if the passage unit is already mounted in the slab. Please note that the axis point is 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 the plumb line laser. Such devices automatically align and give an extremely 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. Or you can place it on the floor and send coaxial rays up and down.
Even household models will perfectly cope with the task. No markup assistant needed
And there is one more way of marking, but it will give not an axis, but a contour. Knowing the place of passage of the pipe through the ceiling, and also having the ability to temporarily assemble the chimney, you can bring it to the roof using any levels for orientation in space. Then upper part pipes are wrapped with a sheet of cardboard. This wrapper (sliding along the pipe) is lifted to the roof slope and an oblique cut is made on the cardboard, corresponding to the angle of inclination of the roof in this place. Then the cardboard imitation of the pipe is again brought to the slope and the abutment is circled with a marker.
This way a very precise hole is obtained (by the way, its shape will resemble an ellipse), but do not forget that when passing building structures it is necessary to create technological gaps.