SKF6315YC78Single Row Deep Groove Ball Bearing 75x160x37 mm, Open, Heavy 6300 Series

Product Description

What this part is

A single-row deep groove ball bearing, 75 mm bore × 160 mm outside diameter × 37 mm width, open construction with no seals or shields. Deep groove ball bearings carry radial load with moderate axial load in either direction and, unlike an angular contact bearing, will locate a shaft without a mating unit. The 6300 series is the heavier of the two common medium sections — for the same 75 mm bore, a 6300-series bearing has a larger outside diameter and greater load capacity than the lighter 6200 series (6215), which is the trade the extra housing space buys you.

Decoding the designation

6315 – ISO base number for the single-row deep groove ball bearing with the 75 × 160 × 37 mm envelope.
Y – on deep groove ball bearings a Y suffix is commonly associated with a pressed steel or pressed brass cage rather than the standard steel ribbon cage. This could not be confirmed against a current manufacturer publication for this designation, so the cage material is left blank rather than published as fact.
C78 – a legacy SKF US suffix of the type carried over from the MRC bearing line. It is not present in the current published SKF catalogue and no manufacturer definition could be located, so it is not translated into a tolerance, clearance or preload value. It is retained as a carton marking and search term.

Correcting the source data

The previous listing carried two claims that are not supported and have been removed from the description. First, it stated the bearing was manufactured in the United States; nothing in the manufacturer’s published data or the recorded carton marking supports an origin claim, so none is made. Second, it advertised ABEC5 / P5 precision. ABEC5 and P5 are high-precision tolerance classes usually specified on spindle and instrument bearings, and no source could be found tying either class to the 6315Y C78 designation. That claim should be treated as unverified and is not carried forward as fact. Standard deep groove ball bearings are supplied to normal (P0 / ABEC 1) tolerances unless the designation explicitly says otherwise.

What these specs mean in practice

Precision class is the claim worth being careful about here. Buying a P5 bearing when the machine needs P0 is a waste of money; assuming you have P5 when the bearing is actually P0 means a spindle that will not hold the runout the drawing calls for. Because the class cannot be confirmed for this designation, this bearing should be specified into normal-tolerance service and not relied on for a precision spindle rebuild without measuring it.

Published ratings and mounting data

Catalogue figures below are for the standard SKF 6315 in this envelope. They are a sound guide to the size class, but the Y C78 variant’s cage and internal clearance are unconfirmed, so treat them as indicative rather than certified for this exact part.

Basic dynamic load rating (C): 119 kN
Basic static load rating (C0): 76.5 kN
Fatigue load limit (Pu): 3 kN
Limiting speed: 5 600 r/min
Reference speed: 9 000 r/min
Approximate mass: 3.06 kg

Note that the static rating sits below the dynamic rating, which is normal and expected on a deep groove ball bearing of this size — the two numbers measure different things. Dynamic rating relates to fatigue life under rotation; static rating relates to permanent deformation of a stationary raceway.

Quantity and configuration

One bearing. A single deep groove bearing, not a set, and no snap ring or shield is fitted.

Fitting notes

Mount with the interference fit on the rotating ring — usually the inner ring on a rotating shaft — and press only against that ring so no load passes through the balls. Heating the inner ring evenly to around 80 to 110 °C is preferable to cold pressing on a 75 mm bore of this section. Open bearings are shipped with a preservative rather than a service lubricant, so grease or oil before running.

Interchange guidance

The 6315 base number is used by every major manufacturer, so SKF 6315, FAG 6315, NSK 6315, NTN 6315, Koyo 6315 and Timken 6315 all share the same 75 × 160 × 37 mm envelope and will fit the seat. What varies is cage type, internal clearance (normal, C3, C4) and any seal or shield. The MRC bearing line was absorbed into SKF, which is where the legacy US suffix form comes from.