Weight and balance
Weight is measured in grams, and the tolerance you should accept is roughly plus or minus eight grams from the target. Wider than that and two rackets from the same box will feel like different products to a player who cares.
Balance is the distance from the butt of the handle to the balance point, in millimetres. It is what makes a racket feel head-heavy or manoeuvrable, and it is the specification that most factories treat as an afterthought. We hold plus or minus five millimetres across a production run and it is achievable if you write it down.
Shore hardness and resin
Shore A hardness on the core, sampled across the batch. This is the substitution detector. If the sample read 45 and the production batch reads 38, you are not receiving the racket you paid for, regardless of what the invoice says.
Resin ratio matters for the laminate. Too much resin and the racket is heavy and dead. Too little and it delaminates. You will not measure this on the factory floor, but you can send a cut sample to a laboratory when the order justifies it.
Delamination and grommets
Tap the face and listen. A delaminated area sounds different, and a trained inspector finds it in seconds. It is the defect that turns into a warranty claim four months into your season.
Grommets and the frame protector seem trivial until a thousand rackets arrive with grommets that fall out. Check the fit, check the glue, check that the protector actually follows the frame profile.
What the report should look like
A number, a tolerance, a result, and a photograph when something failed. An AQL table showing the sample size and the accept and reject numbers. A count of major and minor defects. And a recommendation: release, or hold.
No adjectives. No score out of ten. If the report cannot be argued with in front of the factory manager, it is not a report, it is a reassurance, and you did not pay for reassurance.
- Weight ±8 g and balance ±5 mm. Write both into the contract.
- Shore A on the core is your substitution detector. Sample it across the batch.
- Tap-test for delamination. It is fast and it prevents warranty claims.
- A real report has numbers, tolerances, photographs and a hold or release call.
