Please help 1 Give means of caring for the vernier caliper

Please help :

1. Give means of caring for the vernier caliper measuring instruments

2.List five external turning operations of the lathe machine

Thank you

Solution

Q2:-answer:-Turning is a machining process in which a cutting tool, typically a non-rotary tool bit, describes a helical toolpath by moving more or less linearly while the workpiece rotates.
Tapered turning
a) from the compound slide
b) from taper turning attachment
c) using a hydraulic copy attachment
d) using a C.N.C. lathe
e) using a form tool
f) by the offsetting of the tailstock - this method more suited for shallow tapers.
Spherical generation
The proper expression for making or turning a shape is to generate as in to generate a form around a fixed axis of revolution.
a) using hydraulic copy attachment
b) C.N.C. (computerised numerically controlled) lathe
c) using a form tool (a rough and ready method)
d) using bed jig (need drawing to explain).
Hard turning
Hard turning is a turning done on materials with a Rockwell C hardness greater than 45. It is typically performed after the workpiece is heat treated.
The process is intended to replace or limit traditional grinding operations. Hard turning, when applied for purely stock removal purposes, competes favorably with rough grinding. However, when it is applied for finishing where form and dimension are critical, grinding is superior. Grinding produces higher dimensional accuracy of roundness and cylindricity. In addition, polished surface finishes of Rz=0.3-0.8z cannot be achieved with hard turning alone. Hard turning is appropriate for parts requiring roundness accuracy of 0.5-12 micrometres, and/or surface roughness of Rz 0.8–7.0 micrometres. It is used for gears, injection pump components, hydraulic components, among other applications.
Facing
Facing in the context of turning work involves moving the cutting tool at right angles to the axis of rotation of the rotating workpiece.This can be performed by the operation of the cross-slide, if one is fitted, as distinct from the longitudinal feed (turning). It is frequently the first operation performed in the production of the workpiece, and often the last—hence the phrase \"ending up\".

Parting
This process, also called parting off or cutoff, is used to create deep grooves which will remove a completed or part-complete component from its parent stock.

Grooving

External grooving

Face grooving
Grooving is like parting, except that grooves are cut to a specific depth instead of severing a completed/part-complete component from the stock. Grooving can be performed on internal and external surfaces, as well as on the face of the part (face grooving or trepanning)
Knurling
The cutting of a serrated pattern onto the surface of a part to use as a hand grip using a special purpose knurling tool.
Threading
Both standard and non-standard screw threads can be turned on a lathe using an appropriate cutting tool. (Usually having a 60, or 55° nose angle) Either externally, or within a bore. Generally referred to as single-point threading.
tapping of threaded nuts and holes
a) using hand taps and tailstock centre
b)using a tapping device with a slipping clutch to reduce risk of breakage of the tap.
threading operations include
a)all types of external and internal thread forms using a single point tool also taper threads, double start threads, multi start threads, worms as used in worm wheel reduction boxes, leadscrew with single or multistart threads.
b) by the use of threading boxes fitted with 4 form tools, up to 2\" diameter threads but it is possible to find larger boxes than this.
Polygonal turning
in which non-circular forms are machined without interrupting the rotation of the raw material.