Every machine shop that advances in success and sophistication eventually has to transition from being a band of craftsmen into operating within a system of defined procedures. The tribe becomes an enterprise. The craftsmanship is still there, but now it is directed toward refining the overall system rather than just making individual parts. At one shop I visited recently, I was privileged to be present at that transition moment—a moment in which the shop decided to pursue ISO certification. During a crew-wide lunch in which long tables were set up near the shop floor, the shop’s owner and manager overseeing the ISO efforts described the aim of the new system of procedures that would define the shop’s processes. The men described how the defined procedures could (and should) change if they proved problematic, but that following standard procedures would define the shop's culture moving forward. The ISO manager then turned to me, as one who has seen and known a lot of shops, and asked if I would comment on why consistency is important in manufacturing.What a big question! But what an important question worthy of an answer. What follows is not what I said. What follows is what I would have said had I composed a concise response. The case for systemization, the case for defined procedures in manufacturing, includes the following. Why consistency? Here are the reasons:Different people performing the same operation in different ways leads to the need for different resources. For example, one machinist may use a tool for a particular job that others do not. Funding different personal preferences produces extra expense.Every error in manufacturing is the result of a variable that slipped beyond the parameters of control. With fewer variables, error-free manufacturing is easier to maintain. Expanded variables from varying procedures means more can go wrong.If team members A and B follow different procedures, then the choice of A or B has an impact on the success of the job. Production shouldn’t be personal.Problems have to be diagnosed, with the diagnosis sometimes running upstream through the supply chain. The cause of a poor outcome in a part or assembly can be discovered if every step leading to the outcome is known. If the machine shop has variable procedures, then the path of diagnosis ends at its door. The more critical the part, the more concerning this is.The shop that knows its procedures knows what procedures are underperforming and therefore can see precisely what to fix to make its next advance.If the way you work is by personal art, then I may or may not be able to learn it. But if the way you work is according to defined steps, I can follow and learn those steps.What would you add? What benefits has systemization brought to your shop? I'd like to revisit this topic by quoting others on their answer to this same big question. Why consistency? Email me.