A Jeweler’s Saw Usability

Note: This is a paper I wrote for a class on usability, its not a normal piece for this blog.  I thought it would be fun to share.

saw1 137x300 A Jeweler’s Saw Usability

A jeweler's saw

As tools and interfaces become more complex the concepts of usability goals and user experience goals seem to grow in importance.  However, these concepts have been applied to every object since early humans started to make complex tools.  Handles were put on pottery mugs in order to make them easier to hold and knives were given a serrated edge to make it easier to cut things.   The application of usability goals and user experience goals to a jeweler’s saw reveals many interesting aspects about these concepts.

Usability goals tend to be more objective and are applied to the object.  The primary usability goals are efficiency, effectiveness, safety, utility, intuitive/learnability and memorizable (sic).  User experience goals are focused on the user, tend to be more subjective and can change depending on the person.  Examples of user experience goals are satisfying, enjoyable, fun, entertaining, helpful, aesthetically pleasing, motivating, engaging, creativity and emotionally fulfilling.   In order to apply these goals to an object and to make sure an object meets as many as possible goals, design principles must be used.  The design principles that will be used in this essay are visibility, feedback, constraints, mapping, consistency and affordance.

It will impossible to have all of above perfect for a jeweler’s saw.  In order to gain in one area, other areas must be compromised and that is called a trade off.  Tradeoffs will occur with a jeweler’s saw in the same way as they do with any object.  The saw can be described with three key parts.  The first part is the handle.  The second part is an adjustable C shaped piece of metal with one thumb screw on the top and one thumb screw on the bottom. The third is the saw blade, which is screwed in place between the bottom and the top of the metal C.  The above image shows all three parts clearly.

If this tool were handed to a random person they most likely would use it improperly.  Most people would know where to hold the saw because the handle offers physical affordance (Rogers 2007, 33).  Most people would not know how, what direction and to what tension to attach the saw blade.  It would be absurd to assume that a random person, with no background knowledge, would purchase this type of saw and use it.  The name “jeweler’s saw” indicates its use.  In addition a jeweler’s saw is not sold in most hardware stores; they are usually purchased form specialty stores, catalogs or websites.  For the purpose of this usability study understanding who the intended user is going to be is needed to make appropriate conclusions (Rogers 2007, 5).

After identifying the needs and establishing requirements for this tool some things can be assumed about the user (Roger 2007, 17).  It can be assumed that the user has been taught how to use a jeweler’s saw.  This assumption is the same that would be used if designing the usability goals of a cockpit for a plane or any other device for a specialist user.  It can be assumed that the person flying the plane has been taught how to fly a plane and is not a random passenger.

When applying the usability goals to this jeweler’s saw some interesting points come to light.   Assuming that the user has been taught how to use the saw its efficiency is obvious, which is how easy is it to use the tool.  It is pretty easy to see that the saw blade goes between the two screws.  At the same time it might be easy to forget that the teeth of the saw blade need to be orientated down.    If the blade is put in properly then the tool’s effectiveness, which is how good the tool is for doing what it is supposed to do, is perfect.  The saw will cut the proper gauge of metal for the blade easily and smoothly.

Safety brings an interesting trade off to the surface.  The purpose of a jeweler’s saw is to cut metal, which is inherently dangerous and not safe.  Making the saw completely safe would make it an ineffective tool and unable to perform its primary purpose of cutting metal effectively.   For a positive relationship between usability and the intended user experience one cannot make the saw completely safe (Rogers 2007, 27).  There is an assumed danger when using this tool and the user knows that and must take responsibility for it.

The nice thing about the utility of a jeweler’s saw is that it does one thing.  The only thing that a saw can be used for is to cut something.  If the saw blade was used for something else, such as prying, the blades are so thin they would most likely snap.   Therefore a jeweler’s saw does provide the appropriate set of functions in order to complete its purpose.

The saw is not intuitive or learnable until someone has taught the user how to use it.  If the user has been taught how to use it, most likely he can figure out how to do it again.  It is pretty memorizable in that way because one of the most common things that jewelers’ do is put saw blades properly in a saw frame.

Since user experience goals are subjective it is harder to evaluate them (Rogers 2007, 15).  This item, if used properly and with accurate instruction, meets many of the goals.  It can be satisfying, enjoyable, helpful, engaging and motivating if it does the job it is suppose to do.  Since the jeweler’s saw does do the job it is designed to do it meets these goals.  If the saw is used properly it also can facilitate creativity in metal design.  In addition, people who like simple tools can find it aesthetically pleasing in its smooth and simple design.

When design principles are applied to this jeweler’s saw some things are obvious..  The first design principle is visibility, which is how easy is it to see how the object works and does what it is suppose to do (Rogers 2007, 31).  An example of an object with high visibility is a bicycle, because with the exposed gears, chain, wheels and pedals it is easy to see how the bike operates and where something has gone wrong when it breaks.  This jeweler’s saw has high visibility; none of the functions are hidden.  This makes it easier to fix something or see when something is broken.

One of the design principles in which a jeweler’s saw ranks high is in feedback.  The saw blade must be at the right tension setting for the saw to work properly.  In order to tell this, the user must put the saw blade into the frame then pluck it.  If the saw makes a flat sound then the blade does not have enough tension, if the sound is sharp then the blade is tense enough.   If there is too much tension the saw blade will pop out and make the flat sound.  When the user is working with the saw cutting metal, if the saw does not slide in and out and remove metal easily then the saw blade is not tense enough.

This jeweler’s saw has few constraints on it.  Even the handle is designed in a way that does not force the user to hold the saw in a particular way.  This is done deliberately because as the user works with the saw it is going to be moved around at many different angles.  In addition the user will want to use different sized saw blades for different types and gauges of metal.  The latching mechanism for the saw frame must be versatile in order to accommodate different saw blade sizes.

In consistency, which is how similar this product is to others, this jeweler’s saw ranks very high (Rogers 2007, 32).  It is almost exactly the same as all jewelers’ saws have been for the last 100 years.  The beauty of this saw is that the user can go anywhere in the world and use the same tool and know how to work with it[1].  The fact that the product has remained the same for several decades demonstrates how well mapped it is.  There are other more modern saws with differently designed handles that force the user to grip the saw in certain ways, but very few jewelers’ use then.  The best known jewelry tool seller, Rio Grande, does not even sell these new grip saws in the 2011 catalog (Rio Grande Catalog 2011, 87).  However they do sell versions of a jeweler’s saw with a replacement for the thumbscrew.

Because this is a real world object it has real affordance not perceived affordance (Rogers 2007, 33).  This jeweler’s saw has adequate affordance, because the handle does afford a place to grab the saw.  It does not force a user to hold it in a certain way.  This design allows more advanced metals workers to do unconventional work with the saw in order to refine details.  A more complex handle design could be restricting to the advance user.

In order to improve the usability of this jeweler’s saw three things come to mind.  First, would be an image on one side of the frame showing the downward facing saw blade in order to remind novice users in which direction to put the saw blade.  Second, place text on the other side of the frame with the message “safety first” and show an image of a cut hand.   The third idea would be to place another image around the handle suggesting where to grip the saw.  This image would be intended for novice users, and maybe this more suggestive saw could be marketed to them.  Adding additional features would cause additional trade-offs and might annoy users, because the simplicity in the design results in an universal tool, which a major advantage.

Bibliography

Sharp, H., Rogers, Y., & Preece, J. (2007). Interaction design: Beyond human-computer interaction. Chichester: Wiley.

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[1] On a personal note, during the summer of 2006 I went to a body art conference in Finland and visited a jewelry studio in Estonia.  I was able to use the saws in both places with no problems because of an accepted universal design.