Lesson 7

Drilling Machines

Part 2

Care of drilling machines

Lubrication

Lubrication of drilling machines is important because of the heat and friction generated by the moving parts. Follow the manufacturer’s manual for proper lubrication methods. Clean each machine after use. Clean dirt from T-slots, grooves, belts and pulleys. Remove chips to avoid damage to moving parts. Put a light coat of oil on all unpainted surfaces to prevent rust. Operate all machines with care to avoid overworking the electric motor.

Special Care

Operations under adverse conditions require special care. If machines are operated under extremely dusty conditions, operate at the slowest speeds to avoid rapid abrasive wear on the moving parts and lubricate the machines more often. Under extreme cold conditions, start the machines at a slow speed and allow the parts and lubricants to warm up before increasing the speeds. Metal becomes very brittle in extreme cold, so do not strike the machines with hard tools. Extreme heat may cause the motor to overheat, so use intermittent or on and off operations to keep the motor running cool.

Types of drilling machines

There are two types of drilling machines used by maintenance personnel for repairing and fabricating needed parts: hand-feed or power-feed. Other types of drilling machines, such as the radial drill press, numerically controlled drilling machine, multiple spindle drilling machine and turret drill press, are all variations of the basic hand and power-feed drilling machines. They are designed for high-speed production and industrial shops

Drilling depth is controlled by a depth-stop mechanism located on the side of the spindle. The operator of the machine must use a sense of feel while feeding the cutting tool into the work. The operator must pay attention and be alert when the drill breaks through the work, because of the tendency of the drill to grab or snag the workpiece, wrenching it free of its holding device. Due to the high speed of these machines, operations that require drilling speeds less than 450 revolutions per minute cannot be performed.

Hand-Feed. The hand-feed drilling machines are the simplest and most common type of drilling machines in use today. These are light duty machines that are hand-fed by the operator, using a feed handle so that the operator is able to “feel” the action of the cutting tool as it cuts through the workpiece. These drilling machines can be bench or floormounted. They are driven by an electric motor that turns a drive belt on a motor pulley that connects to the spindle pulley. Hand-feed machines are essentially high-speed machines and are used on small workplaces that require holes 1/2 inch or smaller. Normally, the head can be moved up and down on the column by loosening the locking bolts.

Vocabulary

lubrication – смазка

manual - руководство по эксплуатации

groove – паз, желоб

pulley – барабан, ролик

chip – щепка

grit - песчинки

rust - ржавчина

adverse – суровый

abrasive – абразивный, вызываемый трением

brittle – ломкий, хрупкий

intermittent – c перерывами, прерывистый

maintenance - [‘meintənəns] – обслуживание, поддержка

power-feed – с автоматической подачей

radial drill press - радиально-сверлильный станок

numerically controlled – цифровой, с цифровым управлением 

turret drill press – [‘tʌrit] - сверлильный станок с револьверной головкой

depth-stop - ограничитель глубины

snag – защемлять, удерживать

wrench free – [rentʃ] - вырывать

holding device - захватное ( зажимное )устройство

light duty – облегченного типа

drive belt - приводной ремень

pulley [‘pʊli]- шкиф

locking bolts - зажимной болт; стопорный болт 

Exercise 1

Find Russian equivalents to the following words in the text. Learn them by heart.

Смазка, следовать, инструкция, правильный, загрязнение, убирать/удалять, щепки, избегать, урон/вред, предотвращать, ржавчина, перегруз, условия (работы), при (условиях), быстрый, согреваться, увеличивать, хрупкий/ломкий, вызывать, перегреваться, с автоматической подачей, с ручной подачей, боковая часть/сторона, с цифровым управлением, быть начеку, основной, благодаря, оборот, в (минуту, секунду), ослаблять, болт.

Exercise 2

Answer the questions.

1) What precautions should be followed by maintenance personnel and why?

2) What are the two main types of drilling machines?

3) What is the simplest and most common type of drilling machines in use today?

4) What kinds of hand-feed drilling machines do you know?

5) How can we move the head of drilling machines?

Exercise 3

Translate into Russian.

1) Luckily for us this incident had caused no harm or any damage to the equipment.

2) Fuel and lubrication were calculated at $1.26 per gallon of diesel fuel plus 20 percent for engine oil, filter, and labor.

3) Check your owner's manual and perform the recommended preseason lubrication and service on your tractors.

4) She sat down to remove her make-up.

5) The presence of rust and corrosion indicates possible moisture invasion and a potential electrical hazard.

6) he bridge is in an extremely dangerous condition

7) In severe cases, nails may become brittle and break easily.

8) He had to withdraw due to a knee injury

9) The Hilda asteroids circle the Sun three times for every two revolutions of Jupiter.

Exercise 4

Match the words to their definitions.

1) rust 2) cause 3) side 4) due to 5) avoid 6) overheat 7) loose 8) brittle

a) make (something, especially something bad) happen b) hard but easily broken c) prevent from happening: d) because of; owing to: e) make or become too hot f) untie or undo g) each of the flat surfaces of a solid object h) a reddish- or yellowish-brown flaking coating of iron oxide that is formed on iron or steel by oxidation, especially in the presence of moisture