The most expensive mistake in small-appliance sourcing is not a bad factory — it is a good factory whose sample was made in a different way from the production run. Here is what we suggest asking, and what a straight answer sounds like.
1. Was this sample made on the production line or in the sample room?
Sample rooms are staffed by the best technicians with unlimited time. Production is not. Ask directly; a factory that admits "sample room" and explains which steps will differ is more trustworthy than one that says "same".
2. Which parts are the final tooling, and which are hand-made?
Early samples often use CNC or 3D-printed internals. Ask for the tooling status per part, and whether the mould is single-cavity (sample) or multi-cavity (production).
3. What is the tolerance on the fit you are showing me?
The gap you see is nominal. Ask for the tolerance band and the worst-case gap. If nobody can answer, the fit was not engineered.
4. Which components are second-sourced, and what happens if the primary fails?
Motor, battery, heating element, and the control board are the four that matter. Dual sourcing protects your lead time; single sourcing protects your consistency. Know which one you are buying.
5. What exactly is being tested, and to what standard?
A "100% tested" claim means nothing without the test list. Ask for the functional test sheet: what is measured, at what threshold, and what percentage fails.
6. What is the realistic lead time — and which step is the bottleneck?
Not the promised date. The bottleneck step. If it is the heating element supplier, you now know what to monitor.
7. Who signs the golden sample, and where does it live?
The golden sample is the contract. It should be signed by both sides, kept sealed at the factory, and photographed. Disputes about "the colour is different" end the moment someone can open a sealed bag.
None of these questions are hostile. A supplier that enjoys them is a supplier worth keeping.