NTNUCFC205D1Four-Bolt Round Piloted Flange Mount Bearing Unit, 25mm Bore, Setscrew Locking, Cast Iron

Product Description

What this part is

A complete housed ball bearing unit in the four-bolt round piloted flange style. The cast iron one-piece housing carries a 70 mm register diameter on the mounting face, so the unit locates itself concentrically in a machined counterbore rather than relying on the bolts for position. Bore is 25 mm (0.984 in). Locking is by two setscrews in the extended inner ring.

Decoding the designation

UC — wide inner ring insert bearing, setscrew locking, spherical outer surface for self-alignment
FC — four-bolt round flange housing with a piloted mounting register
205 — 25 mm bore size code
D1 — NTN series designation for this housing and insert combination
Insert bearing number UC205D1; housing number FC205D1

Housing style and bolt pattern

Four bolts on a 90.0 mm (3.5469 in) bolt circle, giving 63.6 mm (2.5000 in) between adjacent holes. Bolt hole diameter 12.0 mm (0.4687 in). Flange outside diameter 115.0 mm (4.5312 in). Pilot register diameter 70.0 mm (2.7559 in), projecting 6.0 mm (0.2344 in) from the mounting face.

What these specs mean in practice

The round piloted flange transfers radial load into the counterbore shoulder instead of into the bolt shanks, which holds shaft alignment through load reversals better than a plain-faced square flange. The spherical outer race of the insert takes up initial mounting misalignment at installation; it does not accommodate continuous dynamic misalignment. Contact nitrile seals on both faces retain grease and exclude splash, at the cost of a lower speed ceiling than a non-contact arrangement.

Published ratings and mounting data

Bore (d): 25.000 mm / 0.9840 in
Flange outside diameter (L): 115.0 mm / 4.5312 in
Bolt circle diameter (J): 90.0 mm / 3.5469 in
Bolt hole spacing (J1): 63.6 mm / 2.5000 in
Bolt hole diameter (N): 12.0 mm / 0.4687 in
Pilot diameter (H3): 70.0 mm / 2.7559 in
Total housing width (A): 27.0 mm / 1.0625 in
Insert bearing width (B): 34.100 mm / 1.3425 in
Inner ring extension (S): 14.300 mm / 0.5630 in
Flange thickness (A2): 10.0 mm / 0.3906 in
Dynamic load rating: 14.00 kN / 14000 N / 3147 lbf
Static load rating: 7.85 kN / 7850 N / 1765 lbf
Maximum rotational speed: 5900 RPM
Weight: 1.000 kg / 2.212 lb
Operating temperature range: −40 to 120 °C / −40 to 250 °F

Quantity and configuration

1 Pc. Complete housed unit: cast iron round flange housing with the insert bearing and setscrews fitted, relubricatable through the housing grease fitting.

Fitting notes

The pilot register seats in a machined counterbore of 70.0 mm nominal diameter and at least 6.0 mm depth. Shaft seat is a commercial ground 25 mm diameter. The setscrews tighten against the shaft after the flange bolts are drawn down, so the insert settles into its aligned position first.

Interchange guidance

Same-style four-bolt round piloted flange units to the JIS 200 series in 25 mm bore share the housing envelope: Asahi UCFC205, Koyo UCFC205, FYH UCFC205, AMI UCFC205. The two-bolt oval NTN UCFL205 and the four-bolt square NTN UCF205 use the same UC205 insert but a different housing and bolt pattern, so they are related sizes rather than interchanges.