NTNBST40X721EDBTTP4Ball Screw Support Bearing Set – 40 mm ID, 72 mm OD, 15 mm Width, Open, 60 Degree Contact Angle, DBTT Four-Bearing Arrangement

Product Description

What this part is

NTN BST40X721EDBTTP4 angular contact thrust ball bearing for ball screws. NTN files the BST family separately from ordinary angular contact ball bearings: it is a ball screw support bearing, built for axial load and axial rigidity. Bore: 40 mm. Outside diameter: 72 mm. Width per bearing: 15 mm. Four bearings in a DBTT stack, 60 mm across the set. Country of origin: Japan.

Decoding the designation

BST — angular contact thrust ball bearing for ball screws. 40X72 — 40 mm bore, 72 mm outside diameter. 1 — the dimension series within the BST range. E — an NTN execution code. DBTT — a four-bearing arrangement: a back-to-back pair with two further bearings in tandem. P4 — Precision Class: ISO Class 4, ABEC 7. Searchable forms: BST-40X72-1E-DBTT-P4, BST 40X72 1E DBTT P4, BST40X72-1EDBTTP4.

What these specs mean in practice

Contact Angle: 60°. A steep 60° angle puts almost all of the ball load into the axial direction, which is what a ball screw end fixing needs: high thrust capacity and high axial stiffness in a short envelope. Static Load Rating: 70.0 kN (15,737 lbf) per bearing. Dynamic Load Rating: 31.0 kN (6,969 lbf) per bearing. On a 60° thrust type the static rating sitting above the dynamic rating is the normal published relationship. Operating temperature range: -40 to 120 °C.

Quantity and configuration

Four pieces, a factory DBTT set. Two rows bear axial load in one direction and two in the other, so the set locates a ball screw in both directions. Total stack width 60 mm.

Fitting notes

Bore form: round cylindrical. Inner ring face diameters d1 52.4 mm and d2 48.2 mm. Outer ring face diameters D1 59.6 mm and D2 63.7 mm. Chamfer limits r 1.0 mm and r1 0.6 mm. Open on both faces. Weight 0.595 lb (0.270 kg) per bearing.

Interchange guidance

NSK 40TAC72B and FAG 7602040-TVP are the equivalent 60° ball screw support bearings on the same 40 x 72 x 15 mm envelope. NSK 40BTR10 shares the envelope at a 40° contact angle, so it is a related size rather than a substitution.