Precision Bearing FAQ: Grades, Packing, Installation and Certification

Buyers in machine tools, wind energy, medical equipment and aerospace send us much the same handful of questions, about grade choice, protected shipping, mounting and commissioning, OEM customization and DIN-conformity paperwork. They are collected on this page.

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Precision Grade

P4 / P2 · DIN 620

Protected Logistics

Vibration · Humidity

Installation

Mounting · Preload setting

OEM Solutions

Bespoke · Matched sets

Certification

ISO 9001 · DIN conformity

Answers From Our Application Engineers.

Precision Grade Selection

How do I choose between P4 and P2 precision grades?

Under DIN 620 / ISO 492 a P4 bearing holds its bore within ±0.004 mm, with runout at 3 µm — enough for CNC machine tool spindles turning up to 14,000 rpm. P2 tightens those figures to ±0.0025 mm and 1.5 µm of runout, and we recommend it for ultra-precision grinding spindles, wafer-handling machinery and aerospace gyroscopes.

Are P4 / P2 grade bearings always in stock?

Yes. We keep reserved stock for precision work: 7000-C-T-P4S angular contacts, NN30-K-PA-SP cylindrical rollers and super-precision spindle units. Most P4 items leave inside 24 hours, and P2 specimens ship in 2-5 business days carrying the full DIN-conformity certificate set.

Why does my equipment fail to reach its designed accuracy?

Three causes explain most cases: a grade lower than the drawing demanded, since some suppliers ship P0/P6 parts labeled P5; a preload setting that lets the axis drift as heat builds; and accuracy lost on the way to site. Traceability certificates plus a failure analysis carried out on site let us isolate which of the three actually happened.

Protected Precision Logistics

How do you protect micron tolerances during shipping?

Every P4/P2 bearing travels in VCI anti-corrosion packaging, seated in multi-layer EPE foam cradles inside an HDPE outer case. Air freight to Germany, Italy or the US adds G-shock recorders with a 5G threshold and humidity indicators. Climate-monitored containers hold 18-25°C and no more than 55% RH for the whole journey.

What should I do if a shipment shows shock or impact alerts?

Do not mount it. Call our engineers first — a free precision re-inspection report covering runout, raceway condition and preload arrives within 48 hours, and any unit outside tolerance is replaced at no charge. The shockproof guarantee covers 100% of the declared transit value.

Which countries do you serve with precision logistics?

More than 40 countries, among them Germany, Italy, France, the UK, Switzerland, Sweden, the Czech Republic, Mexico, Brazil, Australia, Japan and South Korea. Consignments move door to door on DHL/FedEx Priority, with chartered air freight where a batch of P2 specimens needs it.

Installation & Commissioning

Do you provide on-site installation guidance?

Yes. Video commissioning is free of charge, and engineers travel on site in the US, Germany, Italy, South Korea and Japan. The scope covers shaft and housing tolerance checks, induction heating for mounting, preload calibration on a spindle gauge, and a final runout reading.

How is preload calculated for matched bearing sets?

Preload classes follow the standard three-step scale: Light (L), Medium (M) and Heavy (H). The choice depends on running speed (the n·dm value), the thermal gradient and the rigidity the spindle needs. Preload calculation comes free of charge against your spindle drawing.

Which lubricant should I select for high-speed spindles?

Past an n·dm of 1,000,000 mm/min we recommend a high-speed spindle grease of the Arcanol SPEED2.6 class, or an oil-air system. Where the value passes 1,500,000 we supply units pre-greased at the works, holding ISO Class 5 cleanliness. Lubrication advice is included with any P4/P2 order.

Customized OEM Solutions

Can you supply matched bearing sets to my drawing?

Matched sets can be built to order — DB, DF, DT or quattro arrangements — with tolerance bands picked to your drawing, non-standard preload, HC ceramic balls or sealed variants. Send a specification sheet or a 2D/3D model; non-stock builds typically need 4-8 weeks.

What is the MOQ for OEM precision bearings?

A standard P4 item starts at one piece. For custom-tolerance OEM batches the minimum sits between 10 and 50 sets, set by bore size, and sample precision testing plus short trial runs are available before a long-term agreement is signed.

Precision Certification

Which certificates are included with each shipment?

Each order ships with a certificate of origin naming the plant that produced it, a DIN 620 / ISO 492 conformity report, an individual measurement record for bore, outside diameter and runout, the heat-lot traceability code and an ISO 9001 quality declaration. P2 adds inspection sheets plotted against SPC limits.

How can I verify a bearing is genuine branded?

A unique heat-lot code is engraved on the inner ring of every unit, tracing back to the melt. The maker's origin-verification portal, or the QR label on the box, will confirm it, and every batch also arrives with a signed conformity letter on company letterhead.

Radial and axial runout, raceway profile and noise are all measured on calibrated instruments before any specimen is released.

Corrosion protection, foam cradles, shock recorders and climate-controlled containers carry that integrity door to door in more than 40 countries.

Talk to an application engineer about precision.

Pass us a bearing list, a drawing or the spindle specification. Within 24 hours you receive a formal quotation with the full DIN-conformity package — availability, lead time and the configuration we recommend included.

• Free preload and bearing life calculation
• Drawing review with a matched-set recommendation
• Failure analysis including a photographic raceway report
• On-site commissioning in more than 40 countries

Ready to discuss a precision requirement?

Send a bearing list, a drawing or the spindle specification. Within 24 hours you receive a formal quotation with the full DIN-conformity package — availability, lead time and the configuration we recommend included.

• 01 Send Specification Email the list, the drawing or the spindle data.
• 02 Engineer Review Tolerance and preload are checked by the application team.
• 03 Formal Quotation A certified quote arrives with DIN documents attached.
• 04 Protected Delivery Worldwide precision logistics, door to door.

© SCHAFFLER BEARING ASM · INDEPENDENT COMPATIBLE REPLACEMENT SUPPLY · ISO 9001 · DIN STANDARD