We join shaft sections and dissimilar metals by friction welding, then machine the assembly to final size. One shop handles the weld, the turning, the heat treat callouts and the inspection report.
Most of them are decided before the first cut, at the joint.
Stock over 4,000 mm or a bar size your lathe cannot hold forces a joint. The joint then has to carry the same torque and bending load as the solid section. If nobody sizes it for that, the shaft fails at the weld line, not in the bearing journal where you expected wear.
The bearing seat needs corrosion resistance. The rest of the shaft does not. Welding the two by hand brings in filler metal, distortion and a heat affected zone that machines differently on each side. Your finish callout then holds on one side of the joint and drifts on the other.
Two straight sections can be straight on their own and still come out of the weld with 0.3 mm of runout. That eats the grinding allowance. You either scrap the part or open the tolerance, and both cost more than the weld did.
A joint that looks clean from outside can carry lack of fusion or porosity inside. On a rotating part under load, that is a crack starter. Without a bond check and a runout check after welding, the first sign of trouble is a field failure.
The joint is made in one operation, the geometry is cut after, and every assembly is checked against the drawing.
One section spins, the other is pressed against it. Rubbing speed and axial force bring both faces to a plastic state, and the two materials fuse across the full face. No filler wire, no flux, no manual welder judgment on the joint.
That matters for welded shafts because the bond is a full-face forge bond, not a bead laid around a diameter. It handles stainless to carbon steel, 4140 to 1045, and similar combinations where you want corrosion resistance or wear resistance only where it is needed.
Heat stays local to the joint. The rest of the shaft keeps its original properties, so pre-machined journals do not need to be re-cut after welding.
A welded blank is never concentric on its own. We indicate the assembly on the lathe, then cut journals, shoulders, keyways, splines and threads to the drawing. Bearing seats usually land at Ra 0.8–1.6 μm; seal faces get finer.
When the part is long, we machine between centers or use a steady rest so the joint is supported while the journals are cut. The result is total indicated runout measured against the datums on your drawing, not against the weld line.
Mill-turn centers let us cut cross holes, flats and keyways in the same setup as the turning. Fewer setups means fewer datum shifts, and that is where runout usually creeps in.
After machining, the shaft goes to 100% inspection: diameter, runout, surface finish and, where specified, a bond check on the joint.
Match the method to the load path, the materials and the section size.
| Method | Best for | Watch out for |
|---|---|---|
| Friction welding | Solid round sections, dissimilar metals | Needs a round face and axial force |
| Machined from solid | Short shafts, tight runout | Bar size and stock cost |
| TIG or MIG welding | Odd shapes, low-speed parts | Distortion, filler metal, HAZ |
| Shrink fit or press fit | Temporary or serviceable joints | Slip under reversing torque |
| Spline or keyed joint | Torque transfer, serviceable | Backlash and added length |
One supplier for the joint, the geometry, the finish and the paperwork.
Journals, shoulders, threads and grooves cut to ±0.005 mm. Long parts run between centers.
Keyways, flats, cross holes and splines cut in the same setup as the turning.
Angled holes and compound features on shaft ends and flanges. 16 simultaneous 5-axis centers.
Involute splines and gear teeth on the same shaft, timed to the journals.
Hard chrome, electroless nickel, black oxide, anodizing, polishing and bead blasting.
100% inspection before shipment. Material certs and dimensional reports on request.
| Parameter | Range | Notes |
|---|---|---|
| Diameter | Ø3 mm to Ø400 mm | Larger on request |
| Length | Up to 4,000 mm | Longer parts in sections |
| Tolerance | ±0.005 mm | On turned features |
| Runout after weld | 0.03 mm TIR typical | Holds on most bearing fits |
| Surface finish | Ra 0.2–3.2 μm | Ra 0.8–1.6 μm on bearing seats |
| Joint type | Friction weld | Solid round sections |
| Materials | Carbon steel, stainless, 4140, 17-4PH | Mixed joints supported |
| Lot size | 1 piece to 10,000+ | No minimum order quantity |
Welded, splined, gear, motor and worm shafts are a standing part of our work, not a favor.
Tight enough for bearing seats and seal journals on a welded assembly.
Long shafts and multi-section welded assemblies on machines sized for them.
We flag joint location, datums and finish callouts before you commit to tooling.
Dimensional and runout checks on every shaft. Reports supplied on request.
One prototype or a production run. Same process, same inspection.
Welded shaft sections for motor and driveline parts, machined to the bearing fit after joining.
Long welded shafts with keyways and splines, cut between centers to hold runout.
Stainless journals friction welded to carbon steel bodies, where only the seal area needs corrosion resistance.
Small welded assemblies finished to fine surface requirements, with documentation to match.
When the finished length exceeds what a single bar or machine can handle, or when the two ends need different materials. A pump shaft with a stainless seal journal and a carbon steel body is the common case.
If the part fits inside one bar and one material works, machining from solid removes the joint and the risk that comes with it. We will tell you which one is cheaper on your drawing.
Carbon steel to stainless, 4140 to 1045, 17-4PH to 304, and similar pairs where both are forgeable. We work with the aluminum, stainless, steel, copper and titanium grades listed in our material range.
Combinations with very different melting points or a brittle intermetallic layer at the interface need a closer look. Send the pair and we will say yes or no before quoting.
Away from the highest bending moment and away from bearing seats and seal journals. The middle of a simply supported span is the worst place for a joint under bending.
Put it where the diameter is larger and the stress is lower. If the joint has to sit in a loaded zone, we size the section for it and check the weld after machining.
About 0.03 mm TIR is typical after welding and machining, measured against the datums on your drawing. Tighter is possible on shorter parts or when the journals are ground after welding.
Runout depends on how the assembly is indicated on the lathe. Tell us which surfaces are the datums and we will set up to those.
Yes. We check the bond and the runout after joining, before finish machining. If a joint does not pass, we stop and tell you rather than cut the whole part and find out at final inspection.
Dimensional and runout reports go out with the parts on request, along with material certificates.
Yes, but the order matters. Stress relief after welding and before finish machining reduces movement during turning. Hardening is usually done before final grinding so the hardness does not fight the cutter.
Electroless nickel, hard chrome, black oxide, anodizing and polishing are all available. Masking at the joint is decided per part.
From Ø3 mm up to Ø400 mm in diameter, and up to 4,000 mm in length. Below Ø3 mm the joint is hard to control; above Ø400 mm we would quote it as a special.
There is no minimum order quantity. One prototype and a 10,000-piece run go through the same process.
Quotation and free DFM analysis within 12 hours. Production can start within 24 hours of a released drawing, and parts ship in 3–5 days.
On welded shafts, the answer usually comes back with a note on joint location, datum choice or where the finish callout will be hard to hold. Better to hear it before the steel is cut.
Tell us the load, the materials and the datums. We will come back with a weld-and-machine plan, a price and a DFM note on anything that will be hard to hold.
12-hour quote100% inspectionNo minimum order quantity
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