Tutorial for the preparation of
workers in production

Locksmith workshop

Marking parts with reedging

To obtain a primary skill in spatial marking with re-edging, hollow parts are used, for example, pipes, cases of feed boxes, gearboxes, aprons of lathes, etc.

This exercise looks at an example of how to mark out flanges on a nozzle that has flanges in different planes. It is desirable that the planes of the flanges are pre-machined.

1. They study the drawing, determine the correspondence of the workpiece to the dimensions in the drawing. The internal holes are taken as the base.

2. Bars are installed in each hole.

3. The surfaces of the flanges are painted with a solution of vitriol or varnished.

Installation and alignment of the nozzle on the marking plate (first position) are as follows.

1. The branch pipe is installed on two prisms so that the middle flange rests on the jack (Fig. 281, a).

Rice. 281. Marking the branch pipe with reedging:
a - the first position; b - second position

2. Verify the position of the part on the marking plate. For this:

1. with the help of wedges and linings, they achieve a horizontal position of the hole in relation to the plate; the check is carried out with a thickness gauge along the upper or lower edge of the hole;
2. installed in the same way horizontal position opening of the middle 1 flange;
3. finally check the horizontality of the holes on all flanges with a thickness gauge;
4. with a square with a heel, the perpendicularity of all planes of the flanges to the plane of the marking plate is checked.

Marking and applying risks in the first position is as follows.

1. Measure the diameter of the flange hole 2 with a caliper.

2. Vertical double ruler, based on hole diameter, determine the vertical dimension to the center line.

3. Apply this size marks A - B on all surfaces of the flanges.

4. On the horizontal risk of the middle flange, mark the center point with a compass.

5. Through the center point, draw a vertical risk V - D with a square.

Installation and alignment of the part after re-edging (second position) are as follows.

1. Unfold (turn over) the part at an angle of 90 ° (Fig. 281, b).

2. Verify the position of the part on the plate. For this:

1. apply a square to the plane of the flange so that the previously applied risk A - B is located perpendicular to the plane of the plate along the square;
2. repeat the method of checking the horizontal position of the hole on the plate with a thickness gauge.

Marking and drawing risks in the second position are carried out as follows.

1. Based on the diameter of the hole, determine the size along the vertical line to the center mark.

Rice. 282. Sketch for marking the holes on the flange

2. On the planes of the two flanges, holes are marked with mutually perpendicular risks, where the points on the intersection flange will be the centers of the holes.

3. Pierce the centers of the holes.

4. Compasses check the correct location of the center points in relation to the edges of the hole.

5. With radius R1, circles are drawn on the planes of each flange (Fig. 282).

6. Using a table of chords or geometrically, the circle is divided into a given number of parts.

7. Pierce the centers of the holes for the bolted connection.

8. Two circles are drawn for the holes: one with a radius R2 = d/2 and the other (control) with a radius R2 + 1 mm.

9. Pierce the risks of the main circles.

Holes are drilled according to preliminary markings made marking tool, or by pattern. The use of a template saves time, since the contours of the holes previously marked on the template are transferred to the workpiece. Holes of large diameters are drilled in two steps - first with a drill of a smaller diameter, and then with a drill of the required diameter.

Hole drilling can be through (the drill exits through the drilled hole); deaf (the depth of the hole is less than the thickness of the metal); for threading and reaming. The method of performing these types of drilling is the same, except for blind drilling, in which it is necessary to maintain the required hole depth. To do this, use devices that limit the feed of the drill to the desired depth. If there are no such devices, the machine is stopped after a certain time, the drill is removed and the depth of the hole is measured.

For accurate and fast drilling, the drill must be firmly and correctly fixed in the machine spindle or in the chuck so that it rotates without runout. If the drill beats, the hole will be irregular in shape, and the drill may break.

The workpiece to be drilled is fixed on the machine table with bolts and clamping bars or in a vice mounted on the table.

The pressure on the drill must be uniform and correspond to the hardness of the metal and the diameter of the hole. With soft metal and a small hole diameter, the frequency of rotation of the drill and its feed are increased. At the moment the drill exits the hole, the pressure should be loosened to avoid breakage of the drill. Since the drill heats up during drilling, it should be cooled by interrupting work. When working on machine tools, the drill is cooled with a soapy emulsion. When processing cast iron and bronze, the drill is not cooled. When drilling deep holes you should periodically remove the drill from the hole and free the hole and grooves in the drill from chips.

Rice. 27. Jig for drilling holes in flanges:

1 - support strips, 2 - support disk, 3 - marking disk, 4 - flange, 5 - handle, b-cone, 7 - latch, 8 - clamping bolt, 9 - heel

On fig. 27 shows a jig for drilling holes in flanges for steel pipes. Two support strips 1 are welded to the bottom of the conductor with holes for attaching the conductor to the table of the drilling machine. The support strips are welded to the support disk 2 with a hole in the middle, in which the flange foot 9 freely rotates. The foot has a central hole with a thread for the clamping bolt 8. A marking disk 3 is attached to the foot, on the circumference of which eight recesses are located at the same distance from one another ( respectively the largest number flange holes).

To drill holes, the flange 4 is placed on a marking disk, reinforced by turning the handle 5 and centered using a cone 6.

The conductor is installed on drilling machine so that the center of the drill coincides with the circle on which the holes in the flange are located. The flange is laid on the lining. Then the disk is installed so that the latch 7 falls into the recess on the circumference. After drilling the first hole, the disk is rearranged so that the latch falls into the recess for drilling the next hole.

Due to incorrect or unstable fastening of parts, incorrect sharpening drills, drill flute clogging with chips, insufficient drill cooling, incorrect cutting speed and drill feed, drill breakage occurs. With the wrong selection of drills, their improper fastening and incorrect methods of work, the following types of marriage are possible: the size of the hole is larger than required, an oblique hole, the hole is offset from the intended center, the depth of the hole is greater than required.

When drilling on machines, the following safety rules are followed: rotating parts of machines must have guards; the workpieces were designed to be fixed on the table, and not to be held by hand during the processing; tie the sleeves of the dressing gown tightly; do not take on the rotating cutting tool and spindle; do not take out broken hands cutting tools out of the hole, enjoy for that special devices; do not lean on the machine during operation.

A circle is a closed curved line, each point of which is located at the same distance from one point O, called the center.

Straight lines connecting any point of the circle with its center are called radii R.

A line AB connecting two points of a circle and passing through its center O is called diameter D.

The parts of the circles are called arcs.

A line CD joining two points on a circle is called chord.

A line MN that has only one point in common with a circle is called tangent.

The part of a circle bounded by a chord CD and an arc is called segment.

The part of a circle bounded by two radii and an arc is called sector.

Two mutually perpendicular horizontal and vertical lines intersecting at the center of a circle are called circle axes.

The angle formed by two radii of KOA is called central corner.

Two mutually perpendicular radius make an angle of 90 0 and limit 1/4 of the circle.

Division of a circle into parts

We draw a circle with horizontal and vertical axes that divide it into 4 equal parts. Drawn with a compass or square at 45 0, two mutually perpendicular lines divide the circle into 8 equal parts.

Division of a circle into 3 and 6 equal parts (multiples of 3 by three)

To divide the circle into 3, 6 and a multiple of them, we draw a circle of a given radius and the corresponding axes. The division can be started from the point of intersection of the horizontal or vertical axis with the circle. The specified radius of the circle is successively postponed 6 times. Then the obtained points on the circle are successively connected by straight lines and form a regular inscribed hexagon. Connecting points through one gives an equilateral triangle, and dividing the circle into three equal parts.

The construction of a regular pentagon is performed as follows. We draw two mutually perpendicular axes of the circle equal to the diameter of the circle. Divide the right half of the horizontal diameter in half using the arc R1. From the obtained point "a" in the middle of this segment with radius R2, we draw an arc of a circle until it intersects with the horizontal diameter at point "b". Radius R3 from point "1" draw an arc of a circle to the intersection with a given circle (point 5) and get the side of a regular pentagon. The "b-O" distance gives the side of a regular decagon.

Dividing a circle into N-th number of identical parts (building a regular polygon with N sides)

It is performed as follows. We draw horizontal and vertical mutually perpendicular axes of the circle. From top point"1" of the circle we draw a straight line at an arbitrary angle to the vertical axis. On it we set aside equal segments of arbitrary length, the number of which is equal to the number of parts into which we divide the given circle, for example 9. We connect the end of the last segment with the lower point of the vertical diameter. We draw lines parallel to the obtained one from the ends of the segments set aside to the intersection with the vertical diameter, thus dividing the vertical diameter of the given circle into a given number of parts. With a radius equal to the diameter of the circle, from the lower point of the vertical axis we draw an arc MN until it intersects with the continuation of the horizontal axis of the circle. From points M and N we draw rays through even (or odd) division points of the vertical diameter until they intersect with the circle. The resulting segments of the circle will be the desired ones, because points 1, 2, …. 9 divide the circle into 9 (N) equal parts.

To find the center of an arc of a circle, you need to perform the following constructions: on this arc, mark four arbitrary points A, B, C, D and connect them in pairs with chords AB and CD. We divide each of the chords in half with the help of a compass, thus obtaining a perpendicular passing through the middle of the corresponding chord. The mutual intersection of these perpendiculars gives the center of the given arc and the circle corresponding to it.

Marking parts with reedging

To obtain a primary skill in spatial marking with re-edging, hollow parts are used, for example, pipes, cases of feed boxes, gearboxes, aprons of lathes, etc.

This exercise looks at an example of how to mark out flanges on a nozzle that has flanges in different planes. It is desirable that the planes of the flanges are pre-machined.

1. They study the drawing, determine the correspondence of the workpiece to the dimensions in the drawing. The internal holes are taken as the base.

2. Bars are installed in each hole.
3. The surfaces of the flanges are painted with a solution of vitriol or varnished.

Installation and alignment of the nozzle on the marking plate (first position) are as follows.

1. The branch pipe is installed on two prisms so that the middle flange rests on the jack (Fig. 281, a).

2. Verify the position of the part on the marking plate. For this:

A) with the help of wedges and linings, they achieve a horizontal position of the hole in relation to the plate; the check is carried out with a thickness gauge along the upper or lower edge of the hole;

B) in the same way, the hole of the middle flange is set in a horizontal position;

C) finally check the horizontality of the holes on all flanges with a thickness gauge;

D) with a square with a heel, the perpendicularity of all planes of the flanges to the plane of the marking plate is checked.

Marking and applying risks in the first position is as follows.

1. Measure the diameter of the flange hole 2 with a caliper.

2. With a vertical double ruler, based on the diameter of the hole, determine the vertical size to the center mark.

Fig 281. Marking the branch pipe with reedging: first position; b - second position

3. Apply this size marks A - B on all surfaces of the flanges.

4. On the horizontal risk of the middle flange, mark the center point with a compass.

5. Through the center point, draw a vertical risk V - D with a square.

Installation and alignment of the part after re-edging (second position) are as follows.

1. Unfold (turn over) the part at an angle of 90 ° (Fig. 281, b).

2. Verify the position of the part on the plate. For this:

A) apply a square to the plane of the flange so that the previously applied risk A - B is located perpendicular to the plane of the plate along the square;

B) repeat the method of checking the horizontal position of the hole on the plate with a thickness gauge.

Marking and drawing risks in the second position are carried out as follows.

1. Based on the diameter of the hole, determine the size along the vertical line to the center mark.

2. On the planes of the two flanges, mutually perpendicular risks are drawn, where the intersection points will be the centers of the holes.

3. Pierce the centers of the holes.

4. Compasses check the correct location of the center points in relation to the edges of the hole.

5. With a radius, circles are drawn on the planes of each flange (Fig. 282).

6. Using a table of chords or geometrically, the circle is divided into a given number of parts.

7. Pierce the centers of the holes for the bolted connection.

8. Two circles are drawn for holes: one with a radius R2 - d.12 and the other (control) with a radius R2 + 1 mm.

9. Pierce the risks of the main circles.