When you have a “get ‘r’ done” culture of production and unplanned maintenance, frequent use of improvised tools emerges. Who can blame operators and maintenance personnel with a job to do and a finite time to do it in? In many ways improvising tools represents the kind of attempt at innovation, creativity, and entrepreneurship that should be lauded.

And yet… Who is liable if the tool breaks—dropping a load—or fractures—sending chips flying outward? Generally, the company will be liable and the argument can be made that they are responsible for ensuring that the correct tools are available for the job.

And how can quality be assured? Did the modified channel locks (above) give you shivers? Are you certain that no such tool exists in a toolbox at your location?

There is an extensive improv culture on the web that glorifies the modified tool as embodied creativity. A little time spent Googling “modified tools” would yield plenty to make an engineer shudder.

And yet, on rare occasions a custom tool is justified. Most of the equipment in existence has not been designed for maintainability. At some point you may be called upon to stamp or approve a tool for which you can’t find an alternative.

Here is a proposal for a process for approving improvised tools and devices.

Step 1. Problem Formulation

Document each of the following steps:

• Ask what is the problem addressed by this device? What was the operator or mechanic attempting to do? What job were they trying to get done? Describe the problem in terms as simple and general as possible.
• Search for a standard/commercially-available solution. Look through catalogs for something to solve your problem. Search online. Contact people who do similar work or handle similar equipment. Don’t be ashamed to ask for help: someone’s safety depends upon it.
• Explore alternative solutions. If obvious commercial solutions do not exist, brainstorm different ways to get the job done. Even if you come up with ideas that are inferior to the improvised tool on your desk, document the idea and why it is not suitable.

2. Improvised Device Certification

If the solution is not forthcoming in the problem definition stage, we are forced to look hard at approving the device that has been made. If the tool is robust and generally a candidate for approval (unlike the modified channel locks above), then consider the following measures to maximize safety:

• Perform an FMEA or Kepner-Tregoe Potential Problem Analysis. Document our work in detail for later review. Potential problems should include failure of each component in normal service as well as failure of components under severe service or shock loads. Consider how the tool might be misused and preventive steps to mitigate risk.
• Perform a stress analysis for normal use. Ensure that a robust safety factor (5 or more) is present for the load. If the geometry is complex and finite element analysis is not available, then inspect the part carefully for cracks and plastic deformation. Test the material to ensure you know the yield strength and tensile strength in cases of uncertain material.
• Review the FMEA/PPA and stress analysis with someone who has first-hand experience with use of the device. While a mechanic or operator will not be able to double-check your calculations,  they might be able to look at the free body diagram and point out forces or boundary conditions you missed.

General Questions for Impovised Devices

These questions don’t have right-or-wrong answers, but they generally have impacts upon the analysis that need to be considered.

1. Have the modifications changed the material properties of the original tool? Was heat involved in the modification process? Is the tool used to apply significant forces?
2. Was the shape of the tool changed? Did significant plastic deformation occur in the modification process? (Consider work hardening and the amount of force applied in the tool use process.) Did grinding, cutting, or other material removal occur in the modification process? (Were any sharp edges created?) Are there any attachments welded or fastened on? (Was the attachment for the purpose of gaining extra leverage?)
3. Is the force vector on the tool consistent with the design intention? (Consider bending , tension, compression, torsion, and shear forces.)
4. Can use of the tool be avoided with more disassembly? (Does the tool enable a shortcut?) What would it take to do the job with only commercially available tools?

If safety factors are sufficient to ensure safety under normal conditions, abuse/misuse has been considered, and an FMEA/PPA has been completed and reviewed with mechanics or operators, then just about everything possible has been done to responsibly put the tool back on the floor.