XS Jaw Set-Screw Coupling (all sizes)
Jaw couplings, set-screw · 7 sizes · 104 bores · 2 colours · 300 options in stock
Jaw couplings, set-screw type — the cheaper way into a jaw coupling. The parameters are listed in order of importance: the one at the top decides the most, and no amount of care further down makes up for getting it wrong.
This page lists 300 options: Size D14×L22 / D20×L25 / D20×L30 / D30×L35 … 7 total, Bore 3.5x3.5 / 3.5x4 / 3.5x5 / 3.5x6 … 104 total, Colour / finish Matte silver / Silver, Spider (insert) Blue pad / Green pad / Standard pad, Style / variant Keyway 4x2+Keyway 4x2 / Keyway 4x2+Keyway 5x2.5 / Standard. From ¥6.5.
The parts of this item
Figure 1 — A coupling needs three numbers: both bores, outer diameter, overall length — the two bores may differ, and that is the key point
What each parameter decides
Every parameter below shows the real range available on this page, and what goes wrong if you pick it wrong. Work through them in this order and you will not go far wrong.
| Parameter | Available here | What it decides | If you get it wrong |
|---|---|---|---|
| Size | D14×L22 / D20×L25 / D20×L30 / D30×L35 … 7 total | overall size and the space it needs | it will not fit, or it cannot be fastened down |
| Bore | 3.5x3.5 / 3.5x4 / 3.5x5 / 3.5x6 … 104 total | whether it slips over your shaft or rod | it will not go on, or it sits loose and slips |
| Colour / finish | Matte silver / Silver | appearance and surface finish — usually not the size | only looks and price change; it still fits |
| Spider (insert) | Blue pad / Green pad / Standard pad | the elastic element that takes the misalignment | the wrong hardness either transmits vibration or tears itself apart |
| Style / variant | Keyway 4x2+Keyway 4x2 / Keyway 4x2+Keyway 5x2.5 / Standard | the structural and shape differences | it will not fit, or it will not do the job your mechanism needs |
How to choose, step by step
- Bore at both ends — The two ends can differ — 8 mm to 6.35 mm is normal. A bore more than 0.1 mm oversize will not clamp.
- Outside diameter and length — The OD sets how much torque it can carry and how much inertia it adds.
- Type — Rigid transmits everything including misalignment. Jaw and Oldham absorb it. Disc is rigid but still allows a little. Universal joints handle real angles.
- How it grips — Set screw is cheap and marks the shaft. Clamp leaves the shaft clean — take the clamp. Expansion cone for the largest torque.
How the options on this page are distributed
Figure 2 — how the 300 options on this page are spread across each parameter: the bars on the left show how many options sit in each band, the panel on the right shows the real range of every parameter and how many steps it has.
Variant quick reference
| Size | Bore | Colour / finish | Spider (insert) | Style / variant | Options |
|---|---|---|---|---|---|
| D14×L22 | 3.5x3.5 / 3.5x4 / 3.5x5 / 3.5x6 … 45 total | Matte silver / Silver | Standard pad | Standard | 47 |
| D20×L25 | 3.175x3.175 / 3.175x4 / 3.175x5 / 3.175x6 … 78 total | Silver | Blue pad | Standard | 78 |
| D20×L30 | 3.175x3.175 / 3.175x4 / 3.175x5 / 3.175x6 … 55 total | Silver | Blue pad / Green pad / Standard pad | Standard | 165 |
| D30×L35 | 10x12mm | Silver | Standard pad | Keyway 4x2+Keyway 4x2 | 1 |
| D30×L40 | 10x14mm | Silver | Standard pad | Keyway 4x2+Keyway 5x2.5 | 1 |
| D35×L50 | 10x10 / 10x19 / 12x19 / 19x19 | Silver | Standard pad | Standard | 4 |
| D65×L90 | 16x16 / 25x30 / 25x32 / 25x38 | Matte silver | Standard pad | Standard | 4 |
This table is a summary: one row per Size, with the other parameters available in that group. For an exact combination, use the selector at the top of the page — it shows the single part number and price.
Reading the part numbers
| Part no. | Configuration |
|---|---|
XS-D14L22-3.175x3.175-SV | Size D14×L22 · Bore 3.175x3.175 · Colour / finish Silver · Spider (insert) Standard pad · Style / variant Standard |
XS-D14L22-3.175x3.5-SV | Size D14×L22 · Bore 3.175x3.5 · Colour / finish Silver · Spider (insert) Standard pad · Style / variant Standard |
XS-D14L22-3.175x4-SV | Size D14×L22 · Bore 3.175x4 · Colour / finish Silver · Spider (insert) Standard pad · Style / variant Standard |
You can order by part number or by selecting the parameters. The part number is fastest, but it does not always encode every parameter — the selector on this page is the authority.
8 common mistakes
- Bore to 0.1 mm. An 8 mm bore on a 6.35 mm shaft needs a bushing; without one it slips under load.
- Set screws mark the shaft. On a precision shaft use a clamp type, or mill a flat first.
- A rigid coupling allows no misalignment. Motor and screw that are not coaxial will destroy the bearings at both ends.
- The spider is a wear part. Overload grinds it away — that is the coupling protecting the motor, not a quality problem.
- Large OD at speed needs balancing. Above a few thousand rpm an unbalanced coupling shakes the whole axis.
- Check the clamp screw torque. A clamp that is only finger tight slips exactly like a set screw, and it does it slowly so you blame the motor.
- Measure before you order. Take the old part off and measure it, or send us a photo with the caliper reading — that beats guessing from a model number every time.
- Everything here is in millimetres. Where a size is imperial, convert it: 1" = 25.4 mm, 1/4" = 6.35 mm, 3/32" = 2.38 mm.
When to replace it
You do not replace this until it fails — but "still looks usable" and "still reliable" are two different things. Any one of these and it is time:
- The spider is ground up and shedding crumbs — the elastic element has failed.
- The bore has worn oversize and it slips even when clamped.
- Vibration grows at speed — balance lost, or a disc is cracked.
Fitting and use
Check before assembly
- Wipe every mating surface with a lint-free cloth. No chips, no burrs, no old grease. One chip is enough to make a bearing noisy.
- Measure the fits — shaft, bore, centre height — against nominal. More than 0.02 mm out and you should check whether you have the right part.
- Check the orientation: the side with the shoulder, step or oil hole has to face the right way. Fitted backwards, it is usually scrap on removal.
Assembly
- Press if you can; do not hammer. If you must tap, use a brass or nylon drift and put the force on the ring that is being fitted, never through the raceway.
- For an interference fit, heat to 80–100 °C first (oil bath or hot plate — never an open flame on a bearing). Hot fitting is easier and safer than cold pressing.
- Tighten fasteners in a diagonal pattern in 2–3 stages. Taking one down fully first distorts the housing and cocks the shaft.
Running in
- Turn it by hand first. It should be smooth, with no tight spot and no axial play. If there is a tight spot, loosen and reseat — do not run it in.
- Run it slowly and unloaded for 10–20 minutes, then feel the temperature. A clear rise means too much preload or poor alignment.
- Re-torque the fasteners after running in, then apply load.
Three things not to do
- Do not hammer. It brinells the raceway, you cannot see it, and it whines forever afterwards.
- Do not mix brands or precision classes in a matched pair. The load shares unevenly and the poorer one always fails first.
- Do not skip lubrication on parts that need it. A few hundred hours dry and it seizes.
Matching parts
- Stepper motors and lead screws
- Bushings where the bore does not match
- Spare spiders
Lead time, custom work and shipping
- Stock sizes: dispatched in 1–2 working days, subject to stock
- Custom: non-standard sizes, materials and treatments are possible — send quantity and drawing
- Shipping: from Shenzhen; domestic courier by default, DHL or dedicated line for export
- Volume: quantity pricing available, contact us for a quote
If you cannot find the size you need, or you are not sure which one fits, send us the problem you are solving — what machine it goes on, the dimensions of the part you have, what it has to achieve — and we will match it.