If for a turning job, the length of the work is 200 mm and the taper is 1 : 50, the set over required for the tail stock to achieve the taper is

Concept:

Set over = L × \(\rm \frac{D-d}{2l}\) and K = \(\rm \frac{D-d}{l}\)

Where, K is taper ratio, D = large diameter, d = small diameter, L = length of work, l =  Taper length

Calculation:

Given:

 L = length of work, 1:50 is the taper ratio.

we know that, Set over = L × \(\rm \frac{D-d}{2l}\) and K = \(\rm \frac{D-d}{l}\)

∴ Set-over = L × \(\rm \frac{K}{2}\)

It is given that, taper is 1 ∶ 50. It mearns,

K = \(\rm \frac{1}{50}\)

∴ Set-over = \(\rm \frac{200\times \frac{1}{50}}{2}\) = 2 mm

Additional Information

Set-over on lathe

• Work-piece that can be set up between centres (live and dead centre) can be tapered externally by setting the tailstock of the lathe off-centre.
• If the live centre and the dead centre of the machine are set-over (out of alignment), a turned work-piece will be tapered.
• Work-piece turned will have a taper proportional to the amount of the set-over.
• The method is applicable only to long tapers on long work-pieces.
• But if the work is not too short and if the dead centre is carefully set over very accurate results are obtainable.