TOOL BIT(LATHE)

 

The term tool bit generally refers to a non-rotary cutting tool used in metal lathes, shape, and planer Such cutters are also often referred to by the set-phrase name of single-point cutting tool. The cutting edge is ground to suit a particular machining operation and may be resharpened or reshaped as needed. The ground tool bit is held rigidly by a tool holder while it is cutting.

Lathe machine – A father of machines….

Metal lathe  are generic terms for any of a large class of lathes designed for precisely machining relatively hard materials. They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of applications, and a broad range of materials. In . These rigid machine tools remove material from a rotating workpiece via the (typically linear) movements of various cutting tools, such as tool bits and drill bits.

 These machines consist of, at the least, a headstock, bed, carriage and tailstock. These are the mostly used machines in the industry. Various types of jobs can be prepared on these machines.

Headstock

Fig shows the left part of the lathe machine known as headstock with different components.

The headstock (H1) houses the main spindle (H4), speed change mechanism (H2,H3), and change gears (H10), The feedscrew (H8) is a long driveshaft that allows a series of gears to drive the carriage mechanisms.Both the feedscrew and leadscrew (H9) are driven by either the change gears (on the quadrant) or an intermediate gearbox known as a quick change gearbox (H6) or Norton gearbox.Tumbler gears (operated by H5) are provided between the spindle and gear train along with a quadrant plate that enables a gear train of the correct ratio and direction to be introduced.

 The headstock is required to be made as robust as possible due to the cutting forces involved, which can distort a lightly built housing, and induce harmonic vibrations that will transfer through to the workpiece, reducing the quality of the finished workpiece.

Bed

The bed is a robust base that connects to the headstock and permits the carriage and tailstock to be aligned parallel with the axis of the spindle. This is facilitated by hardened and ground ways which restrain the carriage and tailstock in a set track. The carriage travels by means of a rack and pinion system, leadscrew of accurate pitch, or feedscrew.

 Carriage

carriage with its different parts.

In its simplest form the carriage holds the tool bit and moves it longitudinally (turning) or perpendicularly (facing) under the control of the operator. The operator moves the carriage manually via the handwheel (5a) or automatically by engaging the feedscrew with the carriage feed mechanism (5c), this provides some relief for the operator as the movement of the carriage becomes power assisted. The handwheels (2a, 3b, 5a) on the carriage and its related slides are usually calibrated, both for ease of use and to assist in making reproducible cuts.

 Tailstock

fig. shows tailstock with its different parts.

The tailstock is a toolholder directly mounted on the spindle axis, opposite the headstock. The spindle (T5) does not rotate but does travel longitudinally under the action of a leadscrew and handwheel (T1). The spindle includes a taper to hold drill bits, centers and other tooling. The tailstock can be positioned along the bed and clamped (T6) in position as required. There is also provision to offset the tailstock (T4) from the spindles axis, this is useful for turning small tapers.

The image shows a reduction gear box (T2) between the handwheel and spindle, this is a feature found only in the larger center lathes, where large drills may necessitate the extra leverage.

Word of the day-Vitrification

 Vitrification process

Vitrification is a process of converting a material into a glass-like amorphous solid that is free from any crystalline structure, either by the quick removal or addition of heat, or by mixing with an additive. Solidification of a vitreous solid occurs at the glass transition temperature (which is lower than melting temperature, T_m, due to supercooling).

 

Quote of the day …….by priyesh

Best thing you can ever learn in your life is ‘learn to learn‘.

Quote of the day -by Sagar Patel

1. The fruits are at the end of the journey not at the beginning. Take a few more steps: success can be just behind the corner.

Quote of the day -by Priyesh

Difference between extraordinary and ordinay is just………………..EXTRA

quote of the day by priyesh

When your work speaks for itself, don’t interrupt.

Quote of the day -by Priyesh chotai

If a drop of water falls in lake,there is no identity,But if it falls on a leaf of lotus ,it shine like a pearl.So choose the best place or way where you would shine.

Quote of the day -by Priyesh chotai

Workdone W=PV, so , When pressure inceases workdone (by you) increases. So always work in high pressure.That will give you more opportunities to work. 

Word of the day-’Reverse engineering’

Reverse engineering (RE) is the process of discovering the technological principles of a device, object or system through analysis of its structure, function and operation. It often involves taking something (e.g. a mechanical device, electroniccomponent, or software program) apart and analyzing its workings in detail, usually to try to make a new device or program that does the same thing without copying anything from the original