LATHE MACHINE

a. Describe FOUR ( 4 ) chief parts of lathe machine.

Headstock

The headstock contains the headstock spindle and the mechanism for driving it. In the belt-driven type. the driving mechanism consists of a motor-driven cone block that drives the spindle cone block through a thrust belt. The spindle can be rotated either straight or through back cogwheels. When the headstock is set up for direct thrust. a bull-gear pin. located under a screen to the right of the spindle block. connects the block to the spindle. This connexion causes the spindle to turn at the same velocity as the spindle block.

When the headstock is set up for gear thrust. the bull-gear pin is pulled out. unpluging the spindle block from the spindle. This allows the spindle to turn freely inside the spindle block. The back-gear lever. on the left terminal of the headstock. is moved to prosecute the back-gear set with a cogwheel on the terminal of the spindle and a cogwheel on the terminal of the spindle block. In this thrust manner. the thrust belt turns the spindle block. which turns the back-gear set. which turns the spindle. Each thrust manner provides four spindle velocities. for a sum of eight. The back-gear thrust velocities are less slower than the direct-drive velocities. Tailstock

The primary intent of the tailstock is to keep the dead centre to back up one terminal of the work being machined. However. the tailstock can besides be used to keep tapering shank drills. juicers. and bore chows. It can be moved on the ways along the length of the bed and can be clamped in the coveted place by fastening the tailstock clamping nut. This motion allows for the turning of different lengths of work. The tailstock can be adjusted laterally ( forepart to back ) to cut a taper by loosening the clamping prison guards at the underside of the tailstock. Before insert a dead centre. bore. or juicer. carefully clean the tapering shank and rub out the tapering hole of the tailstock spindle. When clasp drills or juicers in the tapering hole of the spindle. be certain they are tight plenty so they will non go around. If let them to go around. they will hit the tapering hole and destruct its truth.

Passenger car

The passenger car is the movable support for the crossfeed slide and the compound remainder. The compound remainder carries the cutting tool in the tool station. The passenger car travels along the bed over which it slides on the outboard ways. The passenger car has T-slots or tapped holes to utilize for clamping work for tiring or milling. When the passenger car is used for drilling and milling operations. passenger car motion feeds the work to the cutting tool. which is rotated by the headstock spindle. Can be lock the passenger car in any place on the bed by fastening the passenger car clinch prison guard. But do this merely when make such work as facing or parting-off. for which longitudinal provender is non required. Normally the passenger car clinch is kept in the released place. Always travel the passenger car by manus to be certain it is free earlier prosecute its automatic provender.

Bed and Ways

The bed is the base or foundation of the parts of the lathe. The chief characteristic of the bed is the ways. which are formed on the bed’s upper surface and run the full length of the bed. The ways maintain the tailstock and the passenger car. which slide on them. in alliance with the headstock.

B. Name FOUR ( 4 ) sort of occupations that a lathe machine can execute and give a simple account for each occupation.

Facing

Confronting is the machining of the terminal surfaces and shoulders of a workpiece. In add-on to squaring the terminals of the work. confronting provides a manner to cut work to length accurately. Generally. merely light cuts are required since the work will hold been cut to come close length or rough machined to the shoulder.

Turn

Turn is the machining of extra stock from the fringe of the workpiece to cut down the diameter. In most lathe machining operations necessitating remotion of big sums of stock. a series of roughing cuts is taken to take most of the extra stock Then a coating cut is taken to accurately “size” the workpiece.

Boring

Boring is the machining of holes or any interior cylindrical surface. The piece to be bored must hold a drilled or cored hole. and the hole must be big plenty to infix the tool. The deadening procedure simply enlarges the hole to the desired size or form. The advantage of drilling is that a true unit of ammunition hole is obtained. and two or more holes of the same or different diameters may be bored at one scene. therefore guaranting absolute alliance of the axis of the holes.

Tapers

A taper is the gradual lessening in the diameter of a piece of work toward one terminal. The sum of taper in any given length of work is found by deducting the size of the little terminal from the size of the big terminal. Taper is normally expressed as the sum of taper per pes of length or taper per inch of length

c. List FIVE ( 5 ) lathe machine work keeping device.
* Chows
* Face home base
* Drive home base
* Lathe Dogs
* Sweethearts

OXY – ACETYLENE

a. Name and study THREE ( 3 ) sorts of fires in Oxy-Acetylene Gas Welding.

1. Acetylene in air fire.

2. Impersonal fire.

3. Oxidising fire.

B. State FIVE ( 5 ) differences between O and acetylene fond regard accoutrements.

Acetylene| OXYGEN|

Acetylene gas hosiery ( Red ) | Oxygen gas hosiery ( Blue. Green ) |
Left handed regulator thread connexion. | Right handed regulator thread connexion. | Acetylene connexion nuts have bevels or channels cut in them. | Nuts are plain without bevel or channels. | Colour set on ethyne regulator in maroon or ruddy. | It is either bluish or black on O regulator. | The recess force per unit area gauge up to 8 saloon. | The recess force per unit area gauge up to 100 saloon. |

c. Determine FOUR ( 4 ) types of gas welding defect and its bar.

Defect| Prevention|

Uneven weld| By doing a consecutive line before welding. |
Excessively much heat weld| Limit the sum of ethyne and O force per unit area. | Not plenty heat weld| Control the sum of ethyne and O force per unit area ratio. | An oxidised weld| Control the sum of O. |