What the part has to do
- Hold two bearing seats coaxial so the axis does not bind.
- Keep the motor face square to the axis so the rotor does not run eccentric.
- Keep each axis square to the next, because cross coupling is a fight the controller never fully wins.
- Keep mass close to the axis, because inertia at the ends is what the motor has to accelerate.
Material and finish
6061-T6 for almost every bracket. Stiffness matters more here than strength, and 6061 machines and anodises cleanly. 7075 where the section is very thin or the bracket also takes landing loads.
Type II anodise, black, to keep reflections off the lens. Bearing seats masked.
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.
Coaxiality of the bearing seats
Out of line seats make the bearings fight each other, which shows as stepping in the footage.
Motor face perpendicularity
An out of square face makes the rotor run eccentric and the axis wobble.
Axis to axis squareness
Comes from one setup on five axis, not from a tolerance chase across fixtures.
Bearing seat fit and finish
A transition fit becomes a press fit if the seat is anodised, and a press fit distorts a thin housing.
What we hold
| Feature | Held |
|---|---|
| Bearing seat bore | H7 or stated interference |
| Coaxiality of seats | 0.02 mm |
| Motor face perpendicularity | 0.02 mm |
| Axis to axis squareness | 0.05 degrees |
Normal production figures for this shop, not a best case. Full tolerance reference.
What we need to quote it
- Bearing part number, so the fit comes from its data rather than a guess
- Motor part number and its mounting face
- Payload mass and where its centre of mass sits
- Bearing retention method, shoulder, circlip or compound
- Cable route, slip ring or hollow shaft
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 gimbal brackets and yokes
Why does five axis matter on a small bracket?
Because the difficulty is in relationships, not in any single dimension. Holding the part once means the bearing seats and the motor face are referenced to the same origin, so squareness comes from the machine rather than from how well the part was relocated on a fixture.
Can you machine a bracket from a printed prototype?
Send the model rather than the printed part. A printed prototype has different stiffness and different tolerances, so measuring it tells us less than the geometry does.
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
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OpenMotor mounts and bells
A plate with four holes that decides whether a motor runs cool and whether the replacement one sits the same way the first did.
OpenEnclosures and housings
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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