Timken36690-3/36620B-3Complete Tapered Roller Bearing Cone and Cup Set 5-3/4 in Bore x 7-5/8 in OD Class 3 Precision 36600 Series — Both Halves Included

Product Description

What this part is

This is a complete single-row tapered roller bearing — the 36690 cone paired with the 36620-B cup, from Timken’s 36600 inch series, 5.7500 in (146.050 mm) bore by 7.6250 in (193.675 mm) outside diameter, supplied to Class 3 precision on both halves.

A tapered roller bearing is built as two separately numbered halves. The cone is the inner ring complete with its tapered roller set and cage, and it presses onto the shaft. The cup is the outer ring with the tapered raceway ground into its bore, and it presses into the housing. Most listings in this product family sell one half or the other. This one sells both.

What is and is not included

Both halves are included. You receive the complete bearing: the 36690 cone with its rollers and cage, and the 36620-B cup. There is nothing further to source and nothing to match up. That is worth stating plainly, because the most expensive and most common mistake in buying tapered roller bearings is ordering against a single part number and receiving half a bearing. If you have been comparing this against cone-only or cup-only listings, this is the one that arrives ready to fit.

The set does not include shims, lock nuts, seals or a housing. Endplay shimming is machine-specific and is not supplied with a bearing.

Decoding the designation

36690 — the cone number, from the 36600 inch series. In Timken’s inch numbering the cone and cup are numbered separately within a common series; 36690 and 36691 are cones, 36620 is a cup.The cone number selects the bore. 36690 gives the 5.7500 in / 146.050 mm shaft fit.36620 — the cup number, which fixes the 7.6250 in / 193.675 mm housing fit.B in 36620B — a Timken design-revision letter on the cup. Timken’s own catalogue lists the 36690 / 36620-B pairing under TSF, Tapered Single with Flange, and publishes a flange outside diameter (D1) of 7.7772 in / 197.541 mm with a flange width (C2) of 0.1563 in / 3.97 mm. A flanged cup locates axially against the face of the housing rather than against a shoulder machined inside the bore, which is how a repeatable seat is achieved in a through-bored or thin-walled housing. Check the flange against the photographs before ordering if you are matching an existing installation: a flanged cup will not drop into a housing bored for a plain cup.−3 on both numbers — Timken precision Class 3. The notations 36690-3, 36690 #3 and 36690 *3 all mean the same thing, as do 36620B-3, 36620B #3 and 36620B *3. This is not a quantity, not a packaging code and not a second revision letter.K- prefix forms — K-36690 and K-36620-B are Timken component-order designations for the cone and the cup ordered as loose components. They appear widely in OEM parts lists and are cross-referenced below.

What Class 3 precision actually buys you

Timken supplies inch tapered roller bearings in graded precision classes — Class 4 is the standard commercial grade, then Class 3, Class 0, Class 00 and finer. Each step up tightens the tolerances on bore, outside diameter and width, and critically on the radial and axial runout of the ground raceways.

A Class 3 bearing therefore runs truer than a standard bearing in the same envelope, on the shaft and in the housing alike. It is specified where runout translates directly into a product-quality problem rather than merely into noise: machine tool spindles, precision gearboxes and index drives, printing and converting rolls, gear grinders, paper machine positions. It costs more than a standard bearing and it is stocked far less widely, which is precisely what makes a surplus set worth finding.

The commercial consequence runs both ways. A standard 36690/36620B will fit where a Class 3 set is called for, but it will not run the same, and substituting down a precision class in a precision position is a common and expensive error. In the other direction, if your position only ever needed a standard bearing, a Class 3 set is a free upgrade with no fitting penalty.

The particular advantage of buying the set rather than the halves is that both rings are Class 3. Precision class governs runout on each ring independently, so pairing a Class 3 cone with a standard cup gives you the runout of the standard cup — you pay for precision and get commercial-grade performance. A matched-class set removes that failure mode entirely. Note that this listing does not reproduce the numeric Class 3 runout limits, because those come from Timken’s precision tolerance tables and were not read for this reference — ask if you need the figures certified.

Published ratings and mounting data

The figures below are Timken’s own published data for the complete 36690 / 36620-B single-row assembly — which is exactly what this listing is, so unlike a cone-only or cup-only listing these ratings apply directly to what you are buying. A load rating always belongs to the pair, because capacity is a property of the roller set running between both races.

Cone part number: 36690 — Cup part number: 36620-B — Series: 36600Bore (d): 5.7500 in / 146.050 mmOutside diameter (D): 7.6250 in / 193.675 mmCone inner ring width (B): 1.1250 in / 28.575 mmCup outer ring width (C): 0.9063 in / 23.020 mmOuter ring flange outside diameter (D1): 7.7772 in / 197.541 mmOuter ring flange width (C2): 0.1563 in / 3.97 mmDynamic radial load rating C1 (1 million revolutions, ISO method): 44,200 lbf / 196,000 NDynamic radial load rating C90 (90 million revolutions, Timken method): 11,400 lbf / 50,900 NDynamic axial rating Ca90: 7,220 lbf / 32,100 NStatic radial load rating C0: 88,600 lbf / 394,000 Ne factor 0.37, K factor 1.59, Y factor 1.63G1 factor 366, G2 factor 121, geometry factor Cg 0.177Shaft backing shoulder diameter, frontface (da): 6.02 in / 153 mm; backface (db): 6.1 in / 155 mmHousing backing shoulder diameter, frontface (Da): 7.50 in / 190.5 mmMaximum shaft fillet radius cleared: 0.06 in / 1.5 mmMaximum housing fillet radius cleared: 0.06 in / 1.5 mmEffective centre location: 0.19 in / 4.8 mmCage location relative to frontface (Ab): 0.13 in / 3.3 mm; relative to backface (Aa): 0.04 in / 1 mm

Two figures are deliberately not published here. The assembly width (T) on Timken’s TSF catalogue entry reads 0.375 in, which cannot be reconciled with a 1.1250 in inner ring, and the 1.125 in figure that circulates for the plain 36690 / 36620 assembly comes from distributor mirrors rather than from Timken — so measure the part you are replacing rather than working from either number. Weight is likewise omitted: the catalogue entry shows 0.3 lb, which is not consistent with a bearing of this envelope, and a figure that looks wrong is worse than no figure.

What these specs mean in practice

The K factor of 1.59 is the number that tells you what this bearing is for. K is the ratio of radial to thrust capability set by the cup angle: a higher K means a shallower cup angle and a bearing that is radially strong and comparatively thrust-weak. At 1.59 the 36600 series sits in the middle of the tapered roller range, carrying a genuinely useful axial component alongside its radial load. That is the load mix a gear-driven shaft produces, which is why the series appears in gearbox, pinion and roll positions rather than in pure thrust duty.

The e factor of 0.37 is the threshold in the equivalent-load equation: below an axial-to-radial load ratio of 0.37 the thrust component drops out of the calculation, above it the equation changes form. With e = 0.37, K = 1.59 and Y = 1.63 published above alongside C1, C90, Ca90 and C0, you have everything needed to run a bearing life calculation on this position without asking anyone for data.

Quantity and configuration

Five pieces are on hand, and each piece is one complete cone-and-cup set — one cone plus one cup, making one whole bearing. Five sets is enough to do a multi-position machine in one go with every bearing from the same production vintage and the same precision class, which is the correct way to rebuild a precision drive train. It is a shallow quantity for a Class 3 reference, so if you need more than five, say so early rather than assuming a repeat order will be available.

Fitting notes

The cone presses onto the shaft and the cup into the housing. Both maximum fillet radii are 0.06 in, and both shoulders must clear or the ring will sit cocked and the roller set will run on a skewed load line. Heat-mount the cone or push on the inner ring face with a proper fitting tool, and drive the cup in from the large end of the taper, square to the bore, bearing on the cup face. Never strike a cage, a roller or a raceway — a brinelled raceway is noisy from the first hour of service, and on a Class 3 bearing a single careless blow throws away the entire reason you paid for the precision class.

Tapered roller bearings carry no built-in internal clearance. The operating endplay or preload is created at assembly by how far the cone is drawn up against the cup, and that setting governs bearing life more than any other single variable. In a precision position the machine builder normally specifies it tightly. Set it to specification with a fresh measurement rather than reusing the old shim pack — both rings here are new with unworn raceways, so the stack-up is not the one the old shims were cut for.

Interchange guidance

36690 and 36620 are industry-standard inch designations rather than proprietary Timken codes, so both halves are manufactured by several bearing makers and a 36690/36620B set from any reputable source is dimensionally interchangeable. That widens the sourcing options considerably in both directions — and it is also exactly why the precision class must be checked separately, since the class is not part of the base number. A plain 36690/36620B from any maker is a standard-class set and is not equivalent to this 36690-3 / 36620B-3.

Cross-references: 36690/36620B, 36690-3/36620B-3, 36690/36620-B, 36690 36620B, 36690-36620B, 36690 #3 36620B #3, 36690 *3 36620B *3, K-36690/K-36620-B, K36690 K36620B, 36690/36620. Cone forms: 36690, 36-690, 36690-3, K-36690. Cup forms: 36620B, 36620-B, 36620B-3, K-36620-B, 36620. Sibling cone: 36691. Related cup forms: 36620D and 36620DC double cups, 36620P. Related assemblies: 36691/36620, 36690/36620D, 36690/36620DC.

Central Surplus also stocks the two halves separately, both Class 3: the Timken 36690 cone under SKU B-BS3#LAQ8WA and the Timken 36620B-3 cup under SKU B-BO4#LMZ2UA. If only one of your rings is worn, buy the half you need from those listings. If both are worn, or if you want the runout of the two rings matched to the same class, buy this set.