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Make Quality Better: Eliminate Hammers

Last updated by Jeff Hajek on May 30, 2019

To make quality better, you frequently have to go hunting for problems. One indicator of problems, though, is hard to miss. In heavy manufacturing, you can walk through a facility and hear the sounds of hammers ringing off in the distance.

Let’s start off for a moment and think why people are using hammers in the first place.

  1. The parts are built perfectly to spec, but the tolerance in the design is so tight that the product needs a little ‘oomph’ to get parts together. Think about that. All that design precision goes away when the blows start landing.
  2. The component parts are not to spec. The hammer is a great tool for making things fit, but it doesn’t change the fact that the underlying quality is poor.
  3. The process is not being done correctly. Something might be keyed wrong, or clocked slightly left of where it is supposed to be. The hammer ‘compensates’ for the error.
  4. Jigs and fixtures are poorly designed. Some make it hard to seat parts. Debris can get trapped and makes parts hang up. Some fixtures are just hard to figure out. In any case, the hammer makes things fit.

So, what’s the problem? The problem is that the hammer doesn’t really make quality better. At best, it hides a problem. As worst, it makes things worse.

Hammers can tweak parts out of spec, damage fixtures, mar parts and paint, and errant blows can really muck things up. And that doesn’t even touch on the potential for injury when heavy stuff moves at high velocity.

Here’s my challenge to you. Go on a quest to make quality better in your facility. Hunt down the hammers, and go find the root cause of why they are used. Once you start getting into the mindset that your company doesn’t use extreme force to make things fit together, you’ll be well on your way to making quality better.

And please, tell us about what you uncover in your search.

(This post is one of the items in my article, 17 Lessons I Learned from Japanese Consultants.)

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3 Comments

Tim McMahon · December 5, 2009 at 7:31 pm

Nice post. It helps to illustrate the five whys in order to get to the root cause. Many would stop at the hammers and buy a better hammer. Why do you need the hammer is the better question.

    Jeff Hajek · December 6, 2009 at 6:43 am

    This was one of the more eye-opening things my consultant taught me. It made me start looking at common practices in new ways. Hammers are an accepted part of manufacturing, so it requires challenging assumptions to question whether they should be used.

    Thanks for the comments, Tim. Always good to hear your thoughts.

Il meglio della blogosfera lean #16 — Encob Blog · December 12, 2009 at 11:34 pm

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