Introduction: Archaeology: Repairing and Modifying a Trowel

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When working in the field, it is easy to lose your tools in the sea of trowels since so many of them look alike. Thanks to TechShop this can easily be taken care of!

In order to show how to both repair and modify at the same time, I decided to use one that had a tip broken off. You can see this in the picture that the tip has been sheared off due to use. In addition, the surface is caked with soil from an earlier dig as well as rust throughout. 

The tools that will be used in this project are:
  • A tool for marking the surface
  • Protractor
  • Bench Grinder
In TechShop San Jose, all of these hand tools are available for use, and the grinders are usable after a Safety and Basic Use Course (SBU). 
The Safety Courses Needed: 

Step 1: Repair

When repairing, I tried to stay close to the original design of the tool. Using a protractor and a ruler, I figured what angle I wanted and scratched it in to the surface. The angle itself doesn't really matter, I just chose something and matched it up to each side. In terms of marking, for this specific tool it was fairly easy to do since I scratched through the caked mud and rust.

From there I took the trowel to the bench grinder in the metal shop. 
A few basic rules regarding grinding:
  • Do Not Wear Gloves. When using a tool that is rotating rapidly, there is always a risk of fabric being pulled in to the machine which will result in serious injury. 
  • Always wear safety glasses and ear protection. When using the grinder, be sure to use the plastic shield on the grinder itself as well as wear safety glasses. It is likely that bits of hot metal will fly in your general direction, especially the eyes. In addition, the grinding room is very small and the grinder is very noisy. I definitely recommend using ear protection to preserve the longevity of hearing.
  • Use two hands. It is necessary to brace the tool properly in order to prevent it from getting caught on the wheel, or getting pulled in. To prevent injury, use both hands to run the metal across the grinder.
  • No Aluminum. If aluminum is used on these wheels, it will gunk up the surface and will cause it not to work as well. If you are unsure of what material your tool is, ask a Dream Consultant. If it makes sparks, it's not aluminum!
Grind down the metal on either side up until the line while the tool is aligned horizontal against the wheel. For myself, I allowed a bit of tolerance when dialing down the shape. Inspecting the tool after each pass along the grinding wheel to make sure that the tool was symmetrical. Once the two sides meet at the center of the tool, you should be done! The trowel is now ready to be fully functional in the field.

For a small modification...

Step 2: Modification: Grinding

For the longest time, I heard of people putting a slight blade on the sides of their trowel to make digging easier when in tough soil. Since I was back in the grinding room anyway, I figured I would give this a try.

One note: If you want to refinish the trowel for further modification, sandblast it first. Otherwise the blade will be removed by the blasting.

After I had ground down the sides of the tool to make a new point, I ran the edges at an angle to the wheel. It is still important to use two hands on this step, since there is a greater risk to jamming the metal in to the wheel. Be cautious of finger placement, it would be bad to accidentally run your finger in the the wheel. It is not really necessary to make an extremely sharp edge on the trowel, this isn't going to be doing any heavy duty cutting. Any form of an edge will make cutting through roots easier, and will assist in truing up the sides of an excavation unit. In addition, I also put an edge on the back end of the trowel to make it easier to drag the tool along the soil; a convenient  way to level the surface of a unit. After I was done grinding, I brought to tool to the de-burring wheel briefly. This is of course to get rid of the burrs on the edges just to prevent it from catching on fabric or delivering a nasty cut. Don't run it along this porous wheel too much otherwise it will dull the newly sculpted edge. 

This is essentially it for a basic modification to a trowel to make it easier to dig in the field. The marking and grinding of the trowel really only takes about 15 minutes, and so it's a really quick job that can be done at an in between moment. It is also something that can easily be done on a mass scale, for example if one wanted to modify the tools of an entire team; especially with a couple assistants, it would all expedite the process. There of course is much more that can be done in terms of refinishing or modification, I was going to include it here but a got a bit too much to essentially have two projects in the same Instructable.

For a further personalized trowel, you can see what I did here.