NEMA 286JM Motor Shaft
1-1/4″ diameter × 3″ long, pre-dimensioned to NEMA MG-1 Part 4 spec for 286JM frame motors. A NEMA JM frame, a close-coupled pump mount with a mechanical-seal-compatible shaft. The shaft is shorter than JP (about 2.9″ through 215JM, 3.0″ through 326JM) and carries an axial tapped hole on the shaft end for bolting down the pump impeller.
Dimensions & defaults
| Frame size | NEMA 286JM |
|---|---|
| Frame family | JM mechanical-seal mount |
| Shaft diameter | 1-1/4″ (1.25″) |
| Shaft length | 3″ (3″) |
| Keyseat | 1/4 SQ, 2.53″ long |
| Axial tapped hole | 1/2-13 × 1.12″ deep (for pump impeller retention) |
| Default material | 1045 medium-carbon steel (configurable) |
| Default surface finish | 63 Ra (bearing-grade journal) |
| Source standard | NEMA MG-1 Part 4 |
Material, tolerances, and additional features (extra grooves, set-screw flats, hole patterns) stay editable in the configurator. The drawing's title block stamps "SOURCE: NEMA 286JM" so any deviations from the standard frame spec are visible to your buyer and to us.
Frequently Asked Questions
A NEMA 143T frame motor expects a 7/8″ shaft with a 3/16″ keyseat at a specific length. Get the dimensions wrong and the coupling, pulley, or impeller won't mate. Loading from a frame card guarantees you start with geometry that mates to the standard motor frame. Material and process choices stay yours.
Every frame loads with NEMA MG-1 Part 4 § 4.9 shaft extension tolerances: +0.0000/−0.0005″ for shafts up to and including 1.5″ diameter, +0.0000/−0.0010″ for shafts above 1.5″. Surface finish defaults to 63 µin Ra on shaft journals, which is the NEMA bearing-fit standard. Keyseat dimensions follow ANSI B17.1. You can tighten or loosen any of these in the configurator before placing the order.
Yes. The configurator lets you edit everything. If you change the OD or shaft length, the drawing will still stamp "SOURCE: NEMA 286JM" in the title block, which signals to your buyer (and to us) that the part deviates from the standard frame spec.
Both are close-coupled pump motor mounts with an axial tapped hole in the shaft end for bolting down a pump impeller. JM (mechanical-seal) uses a shorter shaft (~2.9″ for 143–215 frames). JP (packed-pump) uses a longer shaft (~5.9″) to accommodate a sleeve and packing gland.
We cover the most common subfractional through medium-frame sizes (42 through 326), including T-series (143T to 286T), C-face TC variants, JM mechanical-seal mounts (143JM to 326JM), and JP packed-pump mounts (182JP to 326JP). Larger frames (364T+), submersibles, P-Base vertical pumps, and pool/spa motors aren't in this folder yet because they need features the configurator doesn't expose today (splines, integral pipe threads, left-hand threads). Contact us if you need one and we'll add it.
Yes. The cards default to 1045 carbon steel (the most common motor-shaft alloy), but you can switch to 4140 for fatigue strength, 304/316 stainless for washdown or food-grade environments, or any other material in the configurator's material list.