Red Seal Tool and Die Maker key terms

A formal procedure that isolates and de-energizes all energy sources on a machine, then applies personal locks and tags so equipment cannot be started while someone is working on or inside it.

Energy held in a system after shutdown, such as compressed springs, charged hydraulic accumulators, raised rams, or gravity-loaded slides. It must be released or blocked before work begins because isolation alone does not make the machine safe.

Physical barriers, interlocked gates, or presence-sensing devices that keep hands out of the area where a press or machine performs work on the part, preventing crushing and amputation injuries.

A press control arrangement requiring both operator buttons to be held simultaneously so hands are occupied and outside the die area during the stroke; releasing either button stops the ram.

A safety circuit feature that prevents an operator from blocking or tying down one two-hand control button to run the press with one hand, forcing genuine simultaneous actuation on every stroke.

Canada's Workplace Hazardous Materials Information System, which requires suppliers to provide labels and safety data sheets and employers to train workers on hazardous products used in the shop.

A standardized document listing a product's hazards, composition, first-aid measures, handling and storage requirements, and protective equipment needs; it must be accessible to workers who use the substance.

Theoretically exact points, axes, or planes established on a drawing from which dimensions are measured and features are located, providing a consistent reference for machining and inspection.

A symbolic language on drawings that controls form, orientation, location, and runout of features relative to datums, defining allowable variation by tolerance zones rather than by plus/minus limits alone.

The condition where a feature contains the most material allowed by its limits, such as the largest shaft or smallest hole; it is used with bonus tolerance in position and other feature-relating controls.

The condition where a feature contains the least material allowed by its limits, such as the smallest shaft or largest hole, often specified where minimum wall thickness or edge distance must be protected.

A dimensioning method in which all locations are measured from common reference surfaces or lines rather than chained edge to edge, reducing accumulated error and simplifying setup and inspection.

A drawing convention where the view placed to the right of the front view represents the object as seen from the left; standard in Canada and Europe, and identified by the projection symbol on the title block.

A drawing convention where the view placed to the right of the front view represents the object as seen from the right, with the top view above; common in North American practice and marked by its symbol.

A measuring tool with a main scale and a sliding vernier scale that reads outside, inside, and depth dimensions to typically 0.02 mm or 0.001 in, using the alignment of scale graduations.

A precision instrument using a calibrated screw and thimble to measure small dimensions, commonly to 0.01 mm or 0.0001 in, with a ratchet or friction stop to control consistent measuring force.

Precision-ground hardened steel or ceramic blocks of known size, wrung together in combinations to create a reference dimension for calibrating instruments or setting sine bars and height gauges.

A precision bar with two cylinders at a known centre distance, used with gauge blocks to set or measure angles by establishing a right-triangle relationship between height and the cylinder spacing.

A flat, stable reference surface, usually granite or cast iron, used as the base for layout, height-gauge measurement, and inspection so readings are taken from a common true plane.

A measuring instrument that slides on a surface plate to transfer heights and scribe layout lines, often fitted with a dial or digital indicator for precise comparison to a reference dimension.

A thin coating such as bluing applied to a workpiece surface so scribed lines from a height gauge or dividers are clearly visible when transferring drawing dimensions to the part.

A clearance assembly where mating parts slide together by hand with minimal play, used for locating pins, guide posts, and components that must move or be assembled without force.

An interference assembly in which the shaft is slightly larger than the hole and is forced in with a press or thermal shrink, creating a friction grip that resists movement and loosening.

An interference assembly method where the outer part is heated or the inner part chilled so they assemble freely, then lock together with high grip as temperatures equalize.

Locating mating tooling components with hardened ground dowel pins driven into reamed holes so parts repeat their exact relative position after disassembly and reassembly.

A milling method where cutter rotation at the cut moves in the same direction as the feed, producing a thinner chip that starts thick and ends thin, giving better finish but requiring backlash-free machines.

A milling method where cutter rotation opposes the feed direction, so the chip starts thin and grows; it suits older machines with backlash but tends to lift the workpiece and worsen finish.

Lost motion between mating machine components, especially the leadscrew and nut, that occurs when reversing direction and must be compensated or removed to hold accurate dimensions.

A low-friction leadscrew that transmits motion through recirculating steel balls between screw and nut, providing high efficiency, minimal backlash, and long life on CNC machine axes.

A stored value in the CNC control that corrects for the length or radius difference between the tool and the reference position, so programmed coordinates produce the intended part size.

A programmable reference frame, such as G54, that defines where the part zero sits relative to machine home so programs can be written independent of fixture position.

A control function that offsets the tool path by the cutter radius so the programmer can use part geometry directly, and the operator can adjust size by changing the offset value.

A single CNC code block that performs a repeated sequence such as drilling, boring, or tapping with automatic retract, reducing program length and simplifying common holemaking operations.

The gap per side between the punch and die opening, set as a percentage of material thickness, which controls shearing quality, burr height, and stripping and punching forces.

A plate that holds the workpiece down and pulls it off the punch during the upstroke, preventing the part from lifting with the punch and helping control material movement.

A heavy-duty compression spring, often colour-coded by load rating, installed in tooling to provide stripping, pressure-pad, or lift force and to return components after each press stroke.

A hardened, ground cylindrical post that aligns the upper and lower halves of a die set through bushings, maintaining punch-to-die alignment during repeated press strokes.

The precision frame of a stamping tool consisting of upper and lower shoes joined by guide posts and bushings, which carries and aligns the working die components.

The staged process of running a new or repaired tool in the press, checking part dimensions, form, and function, then adjusting clearances, springs, and stops until the tool produces acceptable parts.

Placing thin precision shims under or behind tooling components to adjust height, clearance, or alignment in small controlled increments during assembly and tryout.

A press used to bring mating tooling members together under controlled force so contact points can be identified and relieved, fitting the tool before it goes into production.

A fitting technique using a thin marking compound spread on one surface so contact with its mate shows high spots, which are then relieved until contact is even.

The high-temperature face-centred cubic phase of steel that dissolves carbon; cooling from it at different rates determines whether martensite, bainite, or pearlite forms.

A hard, stressed, body-centred tetragonal phase formed when austenite cools too fast for carbon to diffuse, giving the high hardness and wear resistance needed in tooling but requiring tempering.

The temperature at which steel transforms to austenite during heating; hardening requires soaking above it long enough to dissolve carbon and equalize temperature through the section.

Rapid cooling of austenitized steel in oil, water, air, or salt to form martensite; the medium is chosen to achieve hardness while avoiding cracking and excessive distortion.

Reheating hardened steel to a temperature below the critical range and holding it to reduce brittleness and relieve stress, trading some hardness for toughness depending on the temperature used.

A steel's ability to harden to depth under a given cooling rate, governed mainly by alloy content; it is distinct from maximum achievable hardness, which depends mostly on carbon content.

Steel containing deliberate additions such as chromium, molybdenum, vanadium, or manganese to improve hardenability, wear resistance, toughness, or hot hardness for tooling applications.

A family of steels formulated for cutting, forming, or shaping other materials, classified into water-hardening, shock-resisting, cold-work, hot-work, and high-speed grades by their service demands.

Localized adhesive wear where material transfers and tears between sliding surfaces under pressure, often seen on punches, guide posts, and forming tools; corrected by lubrication, hardness, or coating changes.

A replaceable hardened plate fitted where sliding or repeated contact occurs in a tool, protecting the base component and allowing restoration by replacement rather than major rework.

A structured investigation, using methods such as five-why questioning or fishbone diagrams, that identifies why a tool failed rather than only repairing the visible damage.