Building Prototypes Dan Gelbart part 2 of 18 Safety

Summary

The lesson highlights less-obvious workshop hazards and explains that they can cause severe injuries even when a machine seems slow or nearly stopped. The presenter’s first instruction is to follow the rules of the specific workshop, including requirements for protective equipment such as safety glasses and steel-toed shoes.

Safety Guidance by Tool and Machine

Woodworking Machines

• Woodworking machines can be especially dangerous because their tools are sharp and operate at high surface speeds.
• Keep your hands well away from the blade, including while it is slowing down. A blade that appears almost stopped can still cause a serious cut.
• Use a push stick or another piece of wood when feeding small pieces or when your hands would otherwise need to get close to the blade.
• Never stand behind a circular-saw blade or try to pull a cut piece from that side. If the blade catches the wood, it can pull the wood—and your hand—toward the blade.
• Work from the safe feeding side and keep your hands clear.

Grinders and Grinding Wheels

• Grinding wheels rotate rapidly and can be fragile despite looking sturdy. A damaged wheel may shatter and send fragments flying.
• Do not stand directly in front of an operating wheel. Stand to the side when using the grinder.

Hammers and Hand Tools

• Wear safety glasses when hammering or chiseling, even if you already wear prescription glasses.
• Do not strike hardened steel directly with hardened steel. The impact can chip off a fragment that may fly with enough force to injure someone.
• When a hard-on-hard impact is unavoidable, place a softer material between the pieces.
• The presenter describes two ways to check whether metal is hardened: try filing it, or compare how it bounces when dropped onto a known hardened surface.
• A hammer’s striking face can deform over time. Inspect it and remove the raised, mushroomed edge when needed.

Lathes

• Never touch a rotating threaded workpiece with a finger or rag. Threads can catch and pull a hand into the machine.
• Cloth touching the outside of a rotating part can also wrap around it and draw the hand in.
• Keep loose sleeves, hanging cords, long hair, and anything else that could catch away from rotating parts.
• Brass can pull a cutting tool or drill into the work. The presenter recommends tools designed for brass: lathe tools with a zero rake angle and drills ground flat at the tip to reduce the tendency to grab.
• A drill pulled into brass may also pull a chuck out of the tailstock, creating a risk that it will be ejected.

Drill Presses

• Clamp the workpiece whenever possible. Do not rely on holding it by hand, since it can catch and spin.
• Start a hole with a center drill when needed to guide the larger drill. For a large hole—described as more than about 10 mm—drill in stages, starting with a smaller drill.
• If an awkward part cannot be clamped in a vise, avoid holding it directly. Use locking pliers or a similar secure grip and drill slowly.
• A drill can grab brass and pull it out of the vise or machine.
• Never place a rag beneath the workpiece. If the drill reaches the rag, it can wind it around the bit and pull the work or nearby objects into motion. Use paper instead when a protective layer is needed.

Presses

• A press can look safe because it moves slowly, but it can create enormous force and store substantial energy.
• If a hard or brittle material is compressed beyond its strength, it may break suddenly and send fragments flying. Do not press materials close to their breaking limit.
• Use a strong protective shield, such as the half-inch Lexan shield shown, when pressing materials that could fracture.
• Before bending a part, make sure the material can bend rather than split. The presenter specifically cautions against assuming that hardened steel, 7000-series aluminum, and spring-hardened beryllium copper will necessarily bend safely.

Speakers and Sources

• Dan Gelbart — instructor and demonstrator, identified by the video title and channel.
• No other speakers or external sources are featured.