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close this bookCentring, Drilling Counterboring and Countersinking, Reaming and Tapping on the Drilling Machines - Course: Techniques for Machining of Material. Instruction Examples for Practical Vocational Training
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View the documentIntroduction
View the documentInstruction example 1.1. Distance piece
View the documentInstruction example 1.2. Gib
View the documentInstruction example 1.3. Cylinder
View the documentInstruction example 1.4. Prismatic guideway
View the documentInstruction example 1.5. Stop

Instruction example 1.1. Distance piece

This instruction example describes the manufacture of rotationally symmetrical workpieces with through hole in the chuck by means of the techniques of centring and drilling. Machining is made on the internal circumference of the workpiece.



9 S 20 K (9 = 0.09 % carbon, 20 = 0.2 % sulphur content; K = cold-drawn)


Ø 30 × 60


A 2.5 centre drill; twist drill of Ø 16

Measuring and testing deans

Vernier caliper


Chuck, drill chuck, taper sleeves, drill drift, coolant or lubricant

Required previous knowledge

Reading of drawings, measuring and testing, choice of cutting values

Sequence of operations


1. Measure rough dimensions.

In case of length undersize reject workpiece.

2. Clamp workpiece.

Kind of clamping: chucking in hard chuck jaws. Chuck for Ø 30 mm. Clamp the chuck high in place to make chip removal possible.

3. Clamp tool.

Insert drill chuck into boring sleeve, use taper sleeves, if necessary. Make sure that the axial positions of workpiece and tool correspond. In case of deviations align workpiece with chuck (punch marking in the centre of the workpiece facilitates visual comparison).

4. Set cutting values.

5. Centre.

Note central position, feeding is made by hand.

6. Clamp tool.

Insert taper shank of twist drill into boring sleeve, use taper sleeves, if necessary.

7. Drill Ø 16 mm.

Use coolant, make through hole.

8. Switch off machine.

Before switching off, return tool.

9. Dechuck.

Clean chuck.

10. Make dimensional inspection and visual check.

Make surface inspection and dimensional inspection. Pay attention to cylindricity and surface appearance.
Deburr the bore on both sides with suitable means (counter-bore, triangular scraper). In case of series production centre all workpieces first and then drill.

Distance piece