XB Jaw Clamp Coupling with Keyways D30×L40, Bore 10 (Key 4×2) × 14 (Key 5×2.5)

Jaw couplings, clamp type · 1 option in stock

Jaw couplings, clamp type — the spider takes the misalignment, the clamp does not mark the shaft. 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 1 option, from ¥13.

What this part is

XB jaw clamp coupling, D30×L40, 10 mm keyed bore. Same series as the D30×L35, 5 mm longer — more length means more angular and radial misalignment tolerated, and slightly less torsional stiffness.

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

The parameters that matter

Not every number on a part like this is worth the same. These are the ones that decide whether it fits and works, and what to look at for each.

How to choose, step by step

1. 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.
2. Outside diameter and length — The OD sets how much torque it can carry and how much inertia it adds.
3. Type — Rigid transmits everything including misalignment. Jaw and Oldham absorb it. Disc is rigid but still allows a little. Universal joints handle real angles.
4. 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.

Reading the part numbers

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

1. Bore to 0.1 mm. An 8 mm bore on a 6.35 mm shaft needs a bushing; without one it slips under load.
2. Set screws mark the shaft. On a precision shaft use a clamp type, or mill a flat first.
3. A rigid coupling allows no misalignment. Motor and screw that are not coaxial will destroy the bearings at both ends.
4. The spider is a wear part. Overload grinds it away — that is the coupling protecting the motor, not a quality problem.
5. Large OD at speed needs balancing. Above a few thousand rpm an unbalanced coupling shakes the whole axis.
6. 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.
7. 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.
8. 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.

Telling it apart from lookalikes

Against the D30×L35: L40 tolerates more misalignment and is more forgiving of rough alignment. L35 is more compact and a little stiffer, for tight spaces and good alignment.

Confirming it is the right part

This page has one configuration, so there is nothing to choose — which makes confirming that it is the right part more important than studying the specification. Three steps is enough:

1. Measure the mating dimension — the one place this part touches something else: bore, shaft, thread, tube OD, or hex across flats. It is the number people get wrong, and half a millimetre out means it will not fit.
2. Measure the outline and the mounting hole spacing. Two parts that do the same job from two makers often differ by 2–3 mm between holes: it looks like it will fit, and it goes on crooked.
3. Send us two photographs: one general view showing the machine and where the part sits, and one close-up with the caliper reading in shot. If the machine has a nameplate, include it — plenty of these parts are specific to one machine, and the model number locates them faster than dimensions do.

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.