What the part has to do
- Hold the stator square so the airgap does not vary through a revolution.
- Keep the bolt pattern interchangeable across a fleet and across a repair.
- Carry thrust and gyroscopic loads into the arm.
- Conduct stator heat away, whether or not it was designed to.
Material and finish
6061-T6 for almost every mount. It is stiffness driven rather than strength driven, it carries heat away from the motor and it anodises evenly. 7075 only where the mount is also a structural arm end.
Type II anodise, clear or black. Hard anodise for agricultural and coastal aircraft. Mask the contact area if the mount is part of the motor ground path.
The features that decide it
Tolerance these. Let everything else on the drawing run to the general tolerance, because it costs money and changes nothing.
Bolt circle true position
Holes drift, the stator sits crooked, the motor runs hot at hover. Held to 0.04 mm in a single setup.
Mating face flatness
The screws are strong enough to pull the stator into whatever shape the mount is.
Centre bore clearance
Clearance, not a fit. A thin plate bows under thrust and closes a gap that looked fine in CAD.
Screw engagement depth
A motor screw 1 mm too long bottoms in the stator and destroys the windings on the first flight.
What we hold
| Feature | Held |
|---|---|
| Bolt circle true position | 0.04 mm |
| Mating face flatness | 0.02 mm over 100 mm |
| Centre bore | Clearance, ±0.05 mm |
| Everything else | General tolerance |
Normal production figures for this shop, not a best case. Full tolerance reference.
What we need to quote it
- Motor model and bolt pattern, named rather than only dimensioned
- Maximum screw length the design allows
- Whether the mount is part of the ground path
- Thrust and aircraft mass, if the plate is thin
- Quantity now and the likely annual quantity
Send what you have. A STEP file and a quantity are enough to start, and the rest sharpens the number.
Read before you draw it
Tools for this part
Run your part through them and send the answers with the model. It makes the quote sharper and the questions fewer.
Questions about motor mounts and bells
Can you machine a mount that fits two motor patterns?
We can, and we would advise against it. A plate drilled for two bolt circles is weaker, heavier and confusing on assembly. Pick the motor first and the mount gets lighter.
Do you turn motor bells as well as mounts?
Yes. Bells, hubs, standoffs and adapters are turned work with live tooling for cross holes, and they come from the same lot traceability as the milled parts.
Quote this part
Send the model and the quantity. Price, lead time and any question that would cost you money if we guessed come back within 24 business hours, EXW, in USD.
Need the full form with tolerances, finish and documents? Open the RFQ page.
Other parts we cut
Arm and boom clamps
The joint that holds the arm on. It has to grip a tube that is never the diameter the catalogue says, without crushing it, and come off again after a season in the weather.
OpenGimbal brackets and yokes
A small part with a hard job. The camera has to point where the controller says it is pointing, through vibration, while weighing as little as possible.
OpenEnclosures and housings
The parts that keep water, dust and spray away from electronics, and the place where most ingress ratings are lost before the gasket is even chosen.
OpenHeat sinks and cold plates
On a small aircraft there is no fan and every gram of heat sink is a gram not spent on battery, so thermal parts are a weight problem wearing a temperature problem as a disguise.
Open