Standard classification of bits

This classification is a three-digit code. The first digit is the bit series number. The letter D before the first digit means the bit is diamond or PCD drag bit. Series D1 to D5 are reserved for diamond bits in the soft, medium soft, medium, medium hard and hard formations respectively. The second digit is the type number. Type O is for PCD drag bits. Types 1-4 designate a formation hardness classification. Feature numbers are interpreted differently, depending on the general type of bit being described.

Eight standard diamond and PCD drag bits features are: step-type profile, long taper profile, short taper profile, non-taper profile, down-hole motor type, side-track type, oil-base type, core-ejector type. The remaining feature (9) is reserved for special features.

The words to be memorized:

1. bottom of the hole - забой

2. drag bit – лопастное долото

3. rolling cutter bit – шарошечное долото

4. blade - лопасть, лезвие

5. integral - цельный

6. body - корпус

7. cone - конус, шарошка

8. axis - ось

9. cutter – режущий элемент, резец

10. solid - сплошной, цельный

11. breakage - поломка

12. junk – металлические обломки, мусор

13. fish tail bit – долото типа «рыбий хвост»

14. uniformly - однородный

15. non-brittle - неломкий, нехрупкий

16. design - конструкция

17. blank - покрытие, слой

18. non-abrasive - неабразивный

19. gummy - липкий, налипающий

20. angle of attack – угол атаки

21. rake – угол резания

22. cutter exposure – величина выступа резца

23. crown profile – профиль шарошки

24. exposed formation - обрабатываемая порода

25. cutter orientation - направления расположения резцов

26. back-rake – наклоненный назад

27. side-rake – наклоненный в бок

28. chip clearance - зазор для выбуренной породы

EXERCISE 2 Answer the following questions.

1.What do all drag bits consist of?

2.What do rolling cutter bits consist of?

3. What is the advantage of drag bits over rolling cutter bits?

4. What are important design features of a РСD bit?

5. What is the most common type used in rotary drilling operations?

6. What does the drilling effect of a rolling cutter bit depend on?

7. While drilling rock, the tooth length and cone offset must be reduced to prevent tooth breakage, mustn’t they?

8. What is standard classification of bits?

9. How are feature numbers interpreted?

10. Is the remaining feature reserved for special features?

EXERCISE 3 Find the proper Russian equivalent to the given English ones.

1. cone 1. неломкий

2. axis 2. режущийэлемент

3. non-brittle 3. Металлические обломки

4. blade 4. липкий

5. cutter 5. профиль шарошки

6. gummy 6. угол резания

7. junk 7. ось

8. rake 8. покрытие, слой

9. crown profile 9. лопасть

10. blank 10. шарошка