Replacing a discontinued motor, repowering an old machine, or fitting a metric motor to an imperial pump? If the new motor won't bolt straight on, you need an adapter machined to both interfaces — send us the two parts for a quote in 24 hours.
When a New Motor Won't Bolt to the Old Machine
A motor rarely fails at a convenient moment, and the replacement rarely matches. The original is discontinued and the modern equivalent is a different frame; a European machine takes an IEC motor and the only one in stock is NEMA; a pump was built around a C-face motor nobody makes any more. The electricals are fine — the mechanical interface is what doesn't fit: the bolt circle is a different diameter, the pilot spigot is the wrong size, the flange is metric where the machine is imperial, or the shaft sits at a different height.
EKINSUN machines the part that bridges that gap. A motor adapter ring or adapter plate carries the new motor's mounting pattern on one face and the old machine's on the other, with the pilot register turned concentric so the motor lands square. We make it from your two mating parts — the motor face and the machine face — with no CAD file and no frame code required, one piece or a batch, quoted within 24 hours.
Adapters We Machine
C-face adapter ring
Ring that re-pitches a NEMA or IEC motor's bolt circle and pilot to the machine's existing face.
Motor adapter plate
Pattern-to-pattern plate — one bolt circle each side, through-bored for the shaft.
NEMA ↔ IEC adapter
Cross-standard: metric B5/B14 motor onto an imperial C-face machine, or the reverse.
SAE pump-mount adapter
Engine or motor SAE flange to a pump housing — pilot interference resolved properly.
Pilot / register ring
Spigot register turned to re-center a motor whose pilot is the wrong diameter.
Adapter + shaft coupler
Flange adapter plus a matching coupler when the shaft diameter changes too.
Interfaces & Standards We Adapt
You don't need to identify any of these — send the parts and we measure them. But if you know the standard, here is what we match:
| Standard | What it is | What we match |
|---|---|---|
| NEMA C-face | Imperial motor face — 42C, 48C, 56C, 143TC–145TC, 182TC–215TC and up | Bolt circle (AJ), pilot register (AK), hole count & size |
| IEC B5 (FF flange) | Metric flange-mount — FF100 through FF350 | Flange OD, bolt circle, spigot register, M-bolt size |
| IEC B14 (FT face) | Metric face-mount — FT65 through FT130 | Tapped bolt circle, spigot register, thread size |
| SAE flange | Engine / hydraulic pump mounts — SAE A through SAE F | Bolt pattern, pilot bore, resolves A-to-B pilot interference |
| Non-standard / OEM | Obsolete or one-off machine faces with no published spec | Reverse engineered from the part itself |
The pilot register is what a catalogue spacer gets wrong. Bolting two flanges together through a plain ring does not center them. If the pilot (spigot register) is missing or the wrong diameter, the motor runs eccentric and chews through the coupling and bearings. We turn the female register to your machine's spigot and the mating register to the motor's in one setup, so alignment is built into the metal — not left to the clearance in the bolt holes.
Materials by Duty
| Material | Best for | Notes |
|---|---|---|
| 6061-T6 aluminium | Most C-face / IEC adapters, light & medium motors | Light, machines clean, corrosion-resistant — the default |
| 7075-T6 aluminium | High-strength plates for heavy cantilevered motors | Higher yield where the adapter carries the motor in bending |
| Cast iron / 1045 steel | Heavy motors, high torque, matching OEM iron adapters | Maximum rigidity and damping; can be painted to match |
| 304 stainless | Washdown, food, humid or outdoor mounts | General corrosion resistance, hygienic finish |
| 316 stainless | Marine and chemical service | Chloride resistance for seawater and coastal plant |
How It Works
Send both faces
The motor and the machine — or marked-up photos with the bolt circle, hole count, hole size and pilot diameter of each. Note the two shaft diameters if the shaft also changes.
We reconstruct both interfaces
We measure and rebuild the CAD for each side free of charge — no frame code, part number or drawing needed. See how we work from a sample.
You approve, we machine
Cut from solid — no casting porosity — with the pilot registers turned concentric in one setup, inspected before shipping.
Reorder anytime
We keep the CAD on file, so a second motor swap on the same machine is a one-line email at a lower unit price.
Who Orders Motor Adapters
"The pump motor is dead and the replacement is a different frame — I need it running this week"
Ship us the machine's mounting face and the new motor. We machine an adapter that bolts to both, register turned concentric, usually in days — so the swap doesn't wait on a redesign or a special-order motor that may not exist.
"Our specified motor went obsolete mid-production and the new one has a different flange"
We machine an adapter so the new motor drops into the existing housing without re-tooling the casting. Repeatable from saved CAD, with material certs for your build documentation — the design stays frozen.
"I repower old units and need adapters between whatever motor the client has and the pump"
We sit behind you as the machine shop: NEMA-to-IEC, SAE pump mounts, pilot rings and the matching shaft coupler, all to fit — so you quote the rebuild without hunting for a frame-matched motor.
"The metric motor on this imported machine failed and I can only source a NEMA one"
Cross-standard adapters are routine here — we machine the metric pattern one side, imperial the other, both to their register, so the locally-available motor mounts as if it were the original.
What Buyers Search When a Motor Won't Fit
Frequently Asked Questions
Yes, that is exactly what an adapter ring or plate is for. Send us the new motor's mounting face and the machine's mounting face — the two parts, or photos with a bolt circle and pilot measurement — and we machine an adapter that carries the new motor's pattern on one side and the old machine's pattern on the other, with the pilot register turned to keep the motor concentric.
Yes. A flange mismatch is usually paired with a shaft mismatch. We machine a matching shaft coupler or bore adapter in the same order so the drive is sorted end to end — the adapter ring aligns the housing, the coupler joins the shafts. Give us both shaft diameters, keyway sizes and the shaft height difference and we quote the pair together.
No. Frame codes help if you have them, but we work from the parts, not the catalogue. Send the motor and the machine — or a marked-up photo with the bolt circle diameter, hole count, hole size and pilot (register) diameter of each — and we reconstruct both interfaces ourselves and machine the adapter to fit.
Yes — cross-standard adapters are one of the commonest jobs. An IEC B5 (FF flange) or B14 (FT face) motor onto a NEMA C-face pump, a NEMA frame onto a metric gearbox, or either onto an SAE pump mount. We machine the metric pattern on one face and the imperial pattern on the other, both to their published register, so the motor lands square and concentric.
Depends on the load and environment. 6061-T6 aluminium for most C-face and light-duty adapters where weight matters; 7075-T6 aluminium or 1045 steel and cast iron for heavy or cantilevered motors that load the adapter in bending; 304 or 316 stainless for washdown, marine and corrosive service. All machined from solid — no casting porosity — with EN 10204 3.1 certificates on request.
Yes, and this is the part catalogue spacers get wrong. Bolting two flanges together through a plain ring does not center them — if the pilot (spigot register) is missing or the wrong diameter the motor runs eccentric and eats the coupling and bearings. We machine a female register to your machine's spigot and a male or female register to the motor's, turned concentric in one setup, so alignment is built into the part rather than left to the bolts.
Related Custom Parts
Motor adapters often ship with the parts around them. We also machine custom flange adapters for pipework and equipment flanges, shaft collars and couplers for the drive side, and full pump replacement parts when the motor swap is part of a larger rebuild. If the motor itself is a discontinued unit, see obsolete part reproduction.
Motor Adapter Quote
Send the two faces or photos. Reply in 24h.
// Qty & price
1 pc
Sample price
Confirm fit before a run
3–10
Unit price drops
Setup cost shared
10+
Best price
All tiers quoted upfront
- →No distributor — you pay the maker directly
- →CAD saved after first order — reorder anytime at lower unit price