The principle is that gratuity is payable to an employee for the continuous service rendered. So whether gratuity is payable for the period of 'daily wages' depends on the definition of continuous service and employee as provided in the Payment of Gratuity Act 1972. The same is reproduced below:
2*["2A. Continuous service.- For the purposes of this Act,--
(1) an employee shall be said to be in continuous service for a period if he has, for that period, been in uninterrupted service,including service which may be interrupted on account of sickness, accident, leave, absence from duty without leave (not being absence in respect of which an order treating the absence as break in service has been passed in accordance with the standing orders, rules or regulations governing the employees of the establishment), lay-off, strike or a lock-out or cessation of work not due to any fault of the employee, whether such uninterrupted or interrupted service was rendered before or after the commencement of this Act;
(2) ..........
Section 2 (e) "employee" means any person (other than an apprentice) employed on wages in any establishment, factory, mine, oilfield, plantation, port, railway company or shop, to do any skilled, semi- skilled, or unskilled, manual, supervisory, technical or clerical work, whether the terms of such employment are express or implied, and whether or not such person is employed in a managerial or administrative capacity, but does not include any such person who holds a post under the Central Government or a State Government and is governed by any other Act or by any rules providing for payment of gratuity.
Reading the two together, if the employee has been continuing in service from 01.01.85 to 31.01.18 and has been discharging basically skilled, semi- skilled, or unskilled, manual, supervisory, technical or clerical work, then the employee is entitled to gratuity for the daily wages period too.