Pump Shaft to Fit Durco Mark 3 Group 2

Dimensioned to the Durco Mark 3 Group 2 power end: 50 mm/50 mm bearing journals (6310/5310), 6-1/2″ (6.5″) bearing span. A Durco Mark 3 (Flowserve) ANSI B73.1 reverse-vane process-pump shaft, dimensioned to the frame group. Threaded impeller end, seal/sleeve seat, inboard and outboard bearing journals (set to the bearing-seat fit), and a keyed drive end with a retaining-ring groove. Both journals are turned to the k5 bearing-seat fit for the rotating inner ring. The coupling end is keyed for the drive coupling. Load it as a configurable starting point, and check the dimensions against your shaft or print before ordering.

Pump Shaft to Fit Durco Mark 3 Group 2 profile (configurator preview)

Dimensions & defaults

Pump modelDurco Mark 3
FrameGroup 2
Radial bearing (inboard)6310, 50 mm journal (1.969″ (1.969″))
Thrust bearing (outboard)5310, 50 mm journal (1.969″ (1.969″))
Bearing-seat fitk5 (light interference, rotating inner ring)
Seal / sleeve seat Ø1-1/2″ (1.5″)
Coupling Ø1-3/8″ (1.375″), 3/8 SQ key
Bearing span6-1/2″ (6.5″)
Overhang (L³/D⁴ index)7-11/16″ (7.688″)
Impeller thread7/8-9 UNC (impeller retention)
Default material4140 alloy steel, annealed (configurable; 316 SS for corrosive service)
Source standardANSI/ASME B73.1 (Durco Mark 3 Group 2)

Tolerances and finish as loaded

Diameter tolerance (default)±.0050″
Length tolerance (default)±.0050″
Angular tolerance±0.5°
Surface finish (default)63 µin Ra
Material (default)4140, cold finished, annealed
Outside cornerschamfer 0.03″
Inside cornersradius 0.015″
Ø 1″ segmenth7 fit (ISO 286): +.0000″ / −.0007″
Ø 1.5″ segmenth7 fit (ISO 286): +.0000″ / −.0010″
Ø 1.9688″ segments (2)k5 fit (ISO 286): +.0006″ / +.0001″
Ø 1.375″ segmenth7 fit (ISO 286): +.0000″ / −.0010″
Keyseat 3/8 SQ0.375″ wide × 0.2124″ deep, ANSI B17.1 3/8 SQ key, 1.05″ long

These are the values the configurator loads for this starting point; every one is editable before you order, and the drawing carries whatever you set.

Configure this part →

Reviewed and quoted: this part is quoted by a person rather than priced instantly because of tight-tolerance fits and its length-to-diameter ratio. Configure it and send it for a quote; quotes typically come back within one business day.

Material, tolerances, and additional features (bearing-journal and seal-fit tolerances, coupling keyseat, retaining-ring grooves, set-screw flats) stay editable in the configurator. Confirm the full machining geometry against your existing shaft or print before ordering. The drawing's title block stamps the source frame so any deviation from the standard is visible to your buyer and to us.

Hubs and collars in the catalog bored for this diameter

Matched on diameter only (±0.0005″); confirm the keyway and fit class against your assembly.

Machined from 4140 by default. See the 4140 material guide, or change the grade in the configurator.

Frequently Asked Questions

By the pump model and frame (Goulds 3196 ST through X17, Durco Mark 3 Group 1 through 3, or a clone such as Summit 2196 MTO), which fixes the bearing journals, seal/sleeve seat, and coupling diameters. Pick the card that matches your pump and load a shaft dimensioned to that frame. Every dimension stays editable in the configurator, and the drawing title block stamps the source frame so any deviation is visible on the print.
Each frame uses a deep-groove radial bearing inboard and an angular-contact thrust bearing (or duplex/double-row pair) outboard. For example, a Goulds 3196 MT runs 6309/7309 (45 mm) and a Durco Mark 3 Group 2 runs 6310/5310 (50 mm). The shaft loads with the journals already set to the k5 bearing-seat fit, a light interference for the rotating inner ring exactly as the OEM manuals specify, with the bearing-seat finish called out. You can adjust any fit in the configurator.
It depends. The Goulds 3196 shares its shaft geometry with a wide family: Goulds' own 3796 self-primer and 3996 vertical in-line mount the same power end, and the parts-clone cluster (Summit 2196, Griswold 811, PumpWorks PWA) copies it, all interchangeable. The Durco Mark 3 is a different geometry: ANSI/ASME B73.1 standardizes the pump envelope, not the shaft. We model each from its own OEM manual. Match the card to your actual pump model, not just the bore.
The cards default to 4140 alloy steel (annealed), the OEM material for sleeved general-duty shafts. For corrosive or solid-shaft service, switch to 316 stainless in the configurator. Material certs (MTRs) are available on request.
The bearing-journal diameters and bearing fits come straight from the OEM installation manuals, with the seal/sleeve, coupling, overhang, and bearing-span dimensions from the OEM data. Check the full machining geometry against your existing shaft or drawing before ordering; every dimension stays editable in the configurator.
We start with the Goulds 3196 (ST through X17), its clone cluster (Summit 2196, Griswold 811, PumpWorks PWA), and the Durco Mark 3 (Group 1 through 3). For a Sulzer, Flowserve non-Durco, or another model, contact us. Those are separate shaft geometries we add as demand warrants.

Goulds, 3196, 3796, 3996, Durco, Mark 3, Summit, Griswold, PumpWorks, and all other pump model, frame, and brand names shown are trademarks or trade names of their respective owners. Great Lakes Shafts is an independent manufacturer and is not affiliated with, sponsored by, or endorsed by any of them. These are aftermarket replacement shafts machined to fit the referenced pumps; the names are used only to identify the equipment our parts fit.