There are two special advantages in having the shop orders numbered. Each foreman knows, when he receives his order, how many operations are ahead of his own and how many follow, and can lay out his work accordingly. It does not always follow, however, that because one foreman receives order No. 3, two other operations must be completed before his own can be started. Each shop order may call for the manufacture of a different part, to be sent to the assembly shop, but if one of these parts is in stock, no order is issued. The foreman receiving order No. 2, when his number naturally would be 3, knows that one of the parts is in stock and that his operation must be hurried accordingly. The employes in the cost department find the numbering system invaluable, for it enables them to tell how many operations there are on a job; also operations which have been completed. This information is of considerable assistance in tracing orders through the shop. The shop order shown in Fig. 43 answers the same purpose as the form shown in Fig. 42. Instead of the system of numbering the order copies, the plan of inserting the names of all shops is followed. Following the name of each shop is the name of the operation to be performed. This also enables the shop foreman to so lay out his work that the order can be handled promptly when it reaches his shop. =25. Work Orders.= The work order is the written instruction of the foreman to the workman to do certain work. As a rule, this order is made on the production time card, as shown in preceding pages. Sometimes, however, it is unnecessary to give more explicit directions than can be written on a small card, which makes it advisable to issue a special order. In certain classes of work, also, it is advisable to use one work order for a job which is to pass through the hands of several men. Such a work order is shown in Fig. 44. This order shows the numbers of the men and machines to which the work is to go. Another class of work for which special orders should be issued is outside repair work──as plumbing, steam fitting, electrical repairs, etc. =26. Standing Orders.= Manufacturing is fast developing into a system of producing standard parts to be assembled into complete machines and appliances. Every part that goes into a machine is made from a standard pattern and is interchangeable with the same part in every other machine of the same style made in the same shop. It is no longer necessary to design each machine, and each part required to fill an order──the parts are manufactured in large quantities and carried in stock till needed. An order from a customer may require the manufacture of one special part, the balance consisting of parts to be assembled.