Double Disk Grinding

Double Disk Grinding Terms Every Buyer Should Know

Double disk grinding terms show up on prints, quotes, and inspection reports. Most of them are never explained. A buyer sees stock allowance, parallelism, free state, and Ra. Each one carries a cost. This guide walks through the grinding terms a buyer or engineer meets when sourcing flat parts. They are grouped by where the words appear.

Knowing the language does more than keep a meeting moving. It helps you write a print a supplier can quote on the first pass. It also helps you tell whether a supplier really runs the process it quotes. At Northern Industrial Manufacturing, these grinding terms come up daily on shims, spacers, thrust washers, and lock plates.

Machine Terms in Double Disk Grinding

Start with the equipment, because several grinding terms describe how a part travels through it.

Wheel and Gap Terms in Grinding

Two grinding terms start at the machine: the wheels are the abrasive discs that face each other. Their cutting surfaces are the faces, not the outside edges. The gap between them sets the finished thickness. When a supplier says it is setting the gap, it is setting your dimension. Dressing means truing the cutting face of a wheel after it wears. That keeps the gap and the finish steady through a long run.

Feed and Carrier Grinding Terms

Two more grinding terms cover movement. Feed describes how parts reach the wheels. In through-feed, parts travel in a straight line from one side of the gap to the other. In rotary feed, a carrier holds parts in pockets and swings them through. A carrier is the plate or fixture that holds parts during the cycle. Changeover is the work of switching a machine from one part to another. It is one reason small lots cost more per piece.

Thickness Terms on a Grinding Print

Most grinding terms on a print describe thickness, and small differences in wording change the price.

Tolerance Terms Used in Grinding

Tolerance grinding terms trip up more buyers than any others. A total tolerance describes the whole allowed band. A 0.001 inch total thickness tolerance means every part must fall inside a 0.001 inch window. Plus or minus 0.001 inch means something different. It allows 0.001 inch above nominal and 0.001 inch below, a 0.002 inch band, twice as wide. Our line holds a 0.001 inch total thickness tolerance. Unilateral means the whole tolerance sits on one side of nominal, such as plus zero and minus 0.001 inch.

Selective Fit Terms in Grinding Programs

Selective fit brings its own grinding terms. Nominal is the target dimension before any tolerance is applied. A thickness step is one part number in a family of shims that share a design but differ in thickness. Selective fit means measuring each unit, then installing the step that brings the stack to target. Stack-up is the accumulated variation of every component in that measurement. The shim exists to correct it.

Flatness and Form Terms in Grinding

Thickness alone does not describe a flat part, so several grinding terms cover shape.

Parallelism Terms After Grinding

Two grinding terms describe form. Flatness describes whether one surface lies in a single plane. Parallelism describes how closely one face follows the other. In practice it is read as thickness variation within a part. A part can hold thickness everywhere and still not be flat. A print should call out both. Free state means the part is measured with nothing holding it down, resting on a surface plate.

Datum and Bow Terms in Grinding

A few more grinding terms come up in flatness discussions. A datum is the reference surface other callouts are measured from. On a flat part, one face is named the datum. The opposite face is controlled to it. Bow is a gentle curve across the part, and a bowed part will rock on a surface plate. These words come up constantly in flatness discussions. They mean the same thing on the floor as in a quality report.

Surface Finish Terms After Grinding

Finish has its own grinding terms, and mixing them is a common source of confusion.

Roughness Terms on Grinding Prints

Roughness grinding terms start with Ra, the average height of peaks and valleys from a mean line. RMS, or root mean squared, is a different calculation of the same surface. The two numbers do not match exactly. A print should say which one applies. Microinch means one millionth of an inch. Our line produces a 10 microinch finish, or 0.25 micrometer.

Stamping Terms That Reach Grinding

Since most ground flat parts start in a press, several grinding terms come from stamping.

Blank and Coil Terms Before Grinding

The first grinding terms from the press describe material. A blank is the flat part as it leaves the die. Coil is the rolled steel the blanks are cut from, and it arrives with its own thickness tolerance. Skeleton scrap is the material left between blanks after stamping. Buyers pay for it even though it goes back as scrap. Compound tooling is a die that cuts the outside and inside features in one stroke. It supports concentricity and a flatter blank.

Stock and Burr Terms in Grinding

Three grinding terms cover the edges and the extra metal. Stock allowance is the thickness left on the blank for the grinder to remove. Burr is the raised edge left by cutting, and deburring or chamfering removes it. Die roll is the slight rounding on one edge, where the metal bent before it separated. Each of these affects how a part grinds and how it seats in an assembly.

Material Grinding Terms Buyers Hear

A few grinding terms describe the steel itself, and they show up whenever hardness enters the conversation.

Steel Grade Grinding Terms

Material grinding terms start with the SAE number, which names the grade of carbon steel. Lower numbers such as SAE 1008 carry less carbon, form easily, and grind quickly. Higher numbers such as SAE 1095 carry more carbon and reach greater strength and hardness. Our line runs that full range. Annealed means the steel has been softened, while hardened means it has been heat treated to raise hardness. We grind parts that arrive already hardened.

Hardness Grinding Terms on a Print

Hardness grinding terms start with the scale, usually Rockwell, written with a letter for the scale and a number for the reading. A print should say whether the hardness applies before or after grinding. Scale is the oxide layer that forms on steel during heat treating, and decarburization, often shortened to decarb, is a thin layer where carbon has been lost at the surface. Grinding removes both, which is one reason hardened parts carry a stock allowance.

Quoting Terms on Grinding Programs

The last group of grinding terms shows up in purchasing and quality conversations.

Ordering Terms for Grinding Programs

Ordering grinding terms start with estimated annual usage, your expected yearly quantity. It drives price more than almost anything else. Lot size is the quantity in one production run. A blanket order commits to a total quantity with scheduled releases against it. Minimum order quantity is the smallest run a supplier will take. Vendor managed inventory means the supplier restocks parts based on what the line actually uses.

Launch and Quality Grinding Terms

Launch grinding terms begin with first article, the first approved part from the production process. Every later part must match it. PPAP, the production part approval process, is the package proving a supplier can hold the print. A control plan lists what gets checked, how often, and with what gauge. Containment and sorting happen when suspect parts must be separated. Both cost enough to be worth avoiding.

Delivery Grinding Terms on Purchase Orders

The last few grinding terms describe how parts reach your dock.

Packaging Grinding Terms

Packaging grinding terms start with dunnage, the material that holds parts in a container, and returnable dunnage travels back to the supplier to be used again. Pack quantity is how many parts go in each container, and it should match how the assembly line consumes them. Rust preventive is the oil or paper used to protect freshly ground steel in transit. Ground faces mark and corrode easily, so packaging belongs on the print or the purchase order, not in a phone call after the first shipment.

Scheduling Grinding Terms

Scheduling grinding terms start with lead time, the span from order to shipment. Release is a call-off against a blanket order, telling the supplier what to ship and when. Safety stock is the buffer a plant keeps to protect the line. Work in process, often shortened to WIP, is material that has been paid for but cannot ship yet. Each of these grinding terms shows up when a program moves from quoting into steady production.

Use Grinding Terms With Your Supplier

Shared grinding terms shorten every conversation about a ground part. A print that carries a total thickness tolerance, a separate flatness callout, a finish in Ra, and an accurate usage estimate can be quoted without a round of questions. When a quote mentions changeover, stock allowance, or lot size, you know what drives the number.

Northern Industrial Manufacturing Corp. stamps on compound tooling and double disk grinds to a 0.001 inch total thickness tolerance. Flatness and parallelism hold 0.001 inch, with a 10 microinch finish, in one IATF 16949 certified plant in the Detroit area. Send us your print. Our team will walk through the callouts and explain what each means for cost and lead time.

Double Disk Grinding Manufacturer

Northern Industrial Manufacturing is your premier parts manufacturer for double disk grinding services. With a reputation for the closest tolerances, highest product quality, short lead times, process innovations, and technical prowess – we can meet your double disk grinding manufacturing needs, while exceeding your expectations and delivering your parts on time and on budget.

If your manufacturing needs calls for precise, dependable double disk grinding, the team at Northern Industrial Manufacturing is ready to support you. Call 586.468.2790 or request a quote today to discuss your project and discover how our double disk grinding services can support your production goals.

Precision Double Disk Grinding Services: 586.468.2790