Lock Picking Set

March 2017   Bianchini-Love

This project spun out of the idea to do a project in one day (this ended up taking 2 days, with a few days in between). Henry and Bibit decided to make a lock picking set because a friend had recently gotten one, which we had grown fond of. Over the course of the project, we used a water jet, a laser cutter, a Prototrak Mill, a lathe, and an Othermill, using materials including steel, aluminum, and two types of wood.

Design and Conception

Since this project began as a 1-day project, we did most of the design ahead of time.  We modeled two of the lock picking implements (a torsion wrench and a rake) off of our friend's lock picking set, copying the profiles and matching the thicknesses.  We designed a third custom tool ourselves, which acts as a screwdriver-like tool for turning the inside doorknob after the lock is removed from the outside (common for certain kinds of locks).

The original lock picking implements which we used as inspiration for the project

After designing these implements, we added in handle features to each of them for convenience.  These handles would be made out of a scrap piece of wood (unidentified -- soft and with sharp grain contrast), held in place over the steel implements using press-fit steel pins.

We designed each of the components in SolidWorks.  We designed the metal parts of the rake and torsion wrench by tracing an image of our friend's lock picking implements then scaling to size.  We designed the turning tool off of dimensions of a standard door lock, then using a simple design to otherwise match the scale and proportions of the other two implements.  We designed the handles and securing pins to be the same size on all three implements.

We then designed a box to house the implements together as a kit.  We had the box designed in two halves:  a tray with holes designed to fit each of the three implements, and a lid with protruding features designed to locate the lid onto the tray while limiting jostling of the implements in the box.  We originally made the tray out of aluminum, then later made both halves out of walnut.

Construction

Implements

We used an OMAX water jet in the MIT Hobby Shop to cut the steel pieces of the implements.  Each of these parts were made out of different thicknesses of steel, with the rake as the thinnest and the turning tool as the thickest.  The water jet was slightly temperamental when we were using it, so it took multiple attempts to obtain one good part of each.

The OMAX water jet

From left to right:  Cut attempts of the turning tool, torsion wrench, and rake

We then used a lathe to turn steel pins that would clearance fit through the holes in these metal pieces and press fit into holes in our wooden handles pieces.  These wooden handle pieces were laser cut out of a thin sheet of wood using a Universal Laser Cutter in MIT MakerLodge.  No adhesives were used, as the press fit between the pins and handle pieces were enough to sandwich the metal parts in place.

The completed lock picking implements from left:  the rake, turning tool, and torsion wrench

The remaining unused handle pieces:  some cracked when press fitting pins into them, others did not laser cut correctly, and others were extras (we clearly needed them).

Box

We began by making the tray part of the box out of aluminum, using a Prototrak Mill in the MIT Hobby Shop.  Each pocket was a different depth to best fit each of the three implements.

The aluminum tray in progress.  This tray was completed by next rounding each of the four corners using a contour operation.

At the end of our first day of machining, we attempted to make a lid out of walnut for the aluminum box.  The pieces did not quite fit together, but we decided to rethink our box design anyway and continued with new plans later.

All of the completed and failed parts made at the end of the first day of building.

At the end of day 1, we decided to test out our tools on our own dorm room!

We pivoted on our box plans and decided to make both the tray and lid out of walnut wood.  Both pieces would have the same profile, and when closed, it would be difficult to see the parting plane between the halves.  To make these pieces, we used two Othermills in MIT MakerLodge.

Our setup to run two Othermills at once.

The tray in the Othermill at the completion of the machining operations (left) and a comparison of the walnut and aluminum trays (right).

At the completion of the project, we had a walnut tray and lid to house the three lock picking implements.