store 
Central Surplus Bearing Finder
A faster way to search our bearing inventory Today we’re launching the Central Surplus Bearing
Availability:
1 in stock
Two-row tapered roller bearing set, 4 in bore, 7-1/8 in OD. Two NA780 cones with one 774D double cup in TDO form, case carburized steel.
List Price
$1,114.35
1 in stock
On the Shelf & Ready to Ship
On all orders
No Risk, No Hassle
| MFR / Brand | Timken |
|---|---|
| MPN | NA780/774D |
| Model | NA 780 / 774 D |
| Bearing Type | Tapered roller bearing cones and double cup (TDO components), Open - no seal |
| ID | 4.0000 in |
| OD | 7.1250 in |
| Width | 4.2500 in |
| Series | 700 |
|---|---|
| Material | Case Carburized Steel |
| Base Number | 780/774D |
| Industry Terms | TDO bearing, double cup tapered roller, two row taper bearing, mill bearing, cone and cup set |
| Common Misspellings | Timkin, Timpken, NA 780 774 D, 774DD |
| Application Types | Rolling mill work rolls, wheel ends, gearbox and conveyor shafts, heavy industrial shafting |
| Bore Shaft Size | 4.0000 in (101.60 mm) |
| Mpn Variants | NA780/774D, NA780 774D, NA-780 774-D, NA780, 774D, 774-D, 780/774D |
| Manufacturer Status | Timken inch tapered series, current |
| Rolling Elements | Tapered Rollers |
| Number Of Rows | 2 |
| Bore Type | Straight |
| Snap Ring Included | Without Snap Ring |
| Harmonization Code | 8482.20.00 |
| Part Number | NA780 / 774D |
Timken two-row tapered roller bearing components in the 780/774 inch series: two NA780 cones and one 774D double cup. Cone bore 4.0000 in (101.60 mm), cup outside diameter 7.1250 in (180.975 mm). Case carburized alloy steel, stamped steel cages, tapered rollers.
780 is the cone number and 774 the cup number in Timken’s inch tapered series. The NA prefix marks a cone furnished for two-row and TDO service, ground to the matched width tolerances that two-row mounting needs. The D suffix on the cup number identifies a one-piece double cup with two raceways, so a single 774D seats two cones back to back.
Three pieces: two NA780 cones and one 774D double cup. Together they form the tapered double outer, or TDO, arrangement — the two cones facing outward against a single common cup.
A TDO arrangement carries thrust in both directions and takes overhung and moment loading, which is why it appears on rolling mill work rolls, wheel ends and screw conveyor shafts. Because both raceways are cut in one cup, the outer clearance is fixed at manufacture and setting happens on the cone side. Case carburized rings give a tough core under a hard raceway, favouring shock loading over through-hardened steel.
The cones mount on a straight cylindrical shaft seat and the double cup presses into a single bore in the housing. Bearing setting is made by adjusting the cone spacing against the shaft shoulder or a spacer, and the cup is located axially by the housing shoulder and cap. Rated limiting speed 3800 rpm.
The plain 780 cone shares the raceway and rollers and is the single-row service version of the same cone. The 782/774D and 783/774D sets use the same 774D double cup on different cone bores — 4.1250 in and 3.9370 in respectively — making them related sizes on a common cup rather than interchanges. The 780/772 set uses the same cone against a single cup for one-direction single-row service.
$61.18
97 in stock
$144.56
12 in stock
A faster way to search our bearing inventory Today we’re launching the Central Surplus Bearing
When an HMI panel goes dark or a PLC module stops communicating, the machine it
If you have ever watched a machine glide smoothly back and forth, tracing a perfect
Our team can locate, cross-reference, and source all parts.
Our team can locate, cross-reference, and source all parts.
Sort
Brand
Price
MPN
Categories
