SealMasterNPL-38Low-Base Two-Bolt Pillow Block Ball Bearing Unit, 2-3/8 in Bore, Setscrew Lock, 2-11/16 in Shaft Centreline, Cast Iron, Relubricatable

Product Description

What this part is

A SealMaster NPL-38 mounted ball bearing unit for a 2-3/8 in shaft — a cast iron two-bolt pillow block on the low-base housing, not a flange block. The insert is a single-row self-aligning ball bearing with a spherical outer diameter and an extended (wide) inner ring, locked to the shaft with setscrews. The spherical seat lets the insert swivel in the housing so the unit accommodates initial shaft misalignment on a real, imperfect frame.

Decoding the designation

SealMaster (now Regal Rexnord) puts the housing family in the prefix and the shaft size in the number, and the number is sixteenths of an inch: 38 = 38/16 = 2-3/8 in bore. Read the letters left to right. N = normal/standard duty. P = pillow block, the two-bolt base-mounted housing. L = low base — SealMaster’s own catalogue describes the NPL series as “NPL Series — Low Base, Setscrew Locking,” used where a low shaft-to-base centreline is needed. That is the whole difference from the NP series: on this 2-3/8 in size the NPL centreline is 2-11/16 in above the base against 2-3/4 in for the equivalent NP. A separate suffix R (as in NPL-20R) means a bore 1/16 in larger than standard for the series — not present here. Flange units in this catalogue carry an F: SF and SFT are the standard-duty four- and two-bolt flanges, MSF the medium-duty four-bolt flange, MFC and SFC the flange cartridges.

Correcting the source data

The source listing called this a “Flange Mount Bearing.” It is not one. NPL-38 is a two-bolt base-mount pillow block and appears in SealMaster’s NPL pillow-block dimension table at 2-3/8 in bore. A flange unit mounts through a vertical face or bulkhead with the shaft passing through the flange; a pillow block bolts down onto a horizontal base beside the shaft. There is no way to substitute one for the other, so a buyer needing a flange who receives this cannot install it. Title, short description and attributes have been corrected. We also confirmed that the “2-3/8” figure in the source data is the bore (shaft size) — not an outside diameter, width or bolt dimension.

What these specs mean in practice

Low base: the reason to specify NPL over NP. If your existing block is an NP, dropping in an NPL lowers the shaft by 1/16 in on this size — trivial on a standalone idler, not trivial on a drive that has to line up with a sprocket or a coupled motor.Setscrew locking: hardened setscrews clamp the extended inner ring to the shaft. Field-serviceable and tolerant of commercial shaft tolerances, but it marks the shaft and is less concentric than a concentric-lock or eccentric-collar design, so avoid it for high-speed or reversing service.Non-expansion: the insert is axially located in the housing. On a two-bearing shaft, only one position may be fixed; the other must float, or thermal growth loads both bearings axially and shortens both lives dramatically.Relubricatable: SealMaster inserts have a lubrication hole and locating dimple in the outer ring, so grease from the housing fitting reaches the raceway.Slotted bolt holes: the base holes are slots, not round holes, giving 6-7/8 to 7-5/8 in of bolt-centre adjustment — that slot range is what lets you tension a drive or square up a conveyor shaft after the frame is drilled.

Published ratings and mounting data

Bore / shaft size: 2-3/8 in (SealMaster size code 38 = 38/16 in)Housing style: two-bolt pillow block, low base, base mountBase to shaft centreline: 2-11/16 inBolt hole centres (slotted): 6-7/8 in minimum to 7-5/8 in maximumOverall housing length: 9-1/2 inMounting bolt size: 5/8 inUnit weight: 13.5 lbReplacement insert: SealMaster 2-26 (standard-duty single-lock, spherical OD, extended inner ring)Housing material: cast iron; insert 52100 bearing steelSeal: felt seal standard; single-lip contact seal (suffix C) and Hi-Temp (250–400°F) available as options in this seriesDynamic and static load ratings: not reproduced here — the catalogue refers them to a load-rating page we could not retrieve in full, and we will not publish borrowed figures. Ask and we will pull them from the printed catalogue.

Quantity and configuration

Price is per unit; two are in stock, which covers both ends of one shaft. Condition is new open-box new-old-stock, Gold Line, made in USA — the carton has been opened but the unit is unused. Each ships complete as housing plus insert with setscrews fitted. Mounting bolts are not included.

Interchange guidance

SealMaster is now a Regal Rexnord brand; 7005955 is the Regal Rexnord item number carried alongside NPL-38, and older paperwork may say SealMaster Gold Line or Stephens-Adamson. Same shaft size, same housing family from other makers: Dodge/Baldor P2B-SC-207 class, Link-Belt P3U238, Browning VPS-238, Timken VPB-238, NTN UCP-2.3/8, SKF SYH 2.3/8. Because this is the low-base housing, verify centreline height and bolt centres before substituting a standard-base block — the shaft height will not be the same. Within SealMaster, NP-38 is the high-base equivalent and NPD-38 the double-lock version.