A Tombstone Fixture is the difference between a part that measures correctly once and a part that measures correctly every time. This page covers a Tombstone Fixture built in a modular grid and reusable clamping kit for aerospace structural machining work: fixture design around drawing datums with clamped, verified location. The tool is designed around the part and the volume rather than copied from a previous job.
In practice the difficulty is rarely the nominal size. repeatability within 0.01 mm is held on the features that locate the part in the assembly, and the process is set up so that the first piece and the five hundredth measure the same way.
Specification
| Process | Fixture design around drawing datums with clamped, verified location |
|---|---|
| Material / configuration | a modular grid and reusable clamping kit |
| Size / capacity | part sizes from 20 to 1200 mm |
| Tolerance | repeatability within 0.01 mm |
| Surface finish | hardened locating pads and clamps |
| Application | tombstone fixture for aerospace structural machining |
| Inspection | Dimensional report, material certificate, first article report on request |
| Lead time | 7–15 working days for samples, 3–4 weeks for production |
| Minimum order | 1 piece for prototypes, from 50 pieces for production pricing |
Manufacturing process
Production begins with a drawing and material review. Stock is certified, the operation sequence is fixed, and fixture design around drawing datums with clamped, verified location is carried out on equipment maintained to hold repeatability within 0.01 mm over a full shift, not just on a first piece.
Material is purchased against a certificate and checked on receipt, so the composition is known before any cutting starts. Work in progress is identified by part number and operation, and the finished parts are deburred, cleaned and protected before they leave the machine area.
Typical applications
Most of the work supplied in this category falls into the following examples.
- Holding thin wall housings for machining.
- Locating parts for robotic welding.
- Assembly of instrument sub-assemblies.
- Drilling hole patterns in repeat batches.
- Inspection of critical interfaces.
Quality control and documentation
Inspection is not a final formality. Dimensions are checked during the cycle and again at the end, so drift is corrected while there is still stock to remove.
Material certificates to EN 10204 3.1, dimensional reports and first article inspection reports are issued with the shipment where the application requires them. Calibration dates and measurement uncertainty are recorded alongside every result.
Ordering, lead time and packaging
Orders start from a single piece. Samples are quoted from the 3D model, and production pricing follows once quantity, finishing and inspection are agreed.
Frequently asked questions
Why build a dedicated fixture instead of using a vice?
A vice locates the part approximately and needs indicating every time. A fixture locates from the drawing datums, so parts are loaded correctly in seconds and measure the same way.
Are fixtures kept between orders?
Yes. Fixtures are retained for the life of the part number, which is why a repeat batch runs on the same setup as the first one with no re-proving.
Do you keep tooling and programmes for repeat orders?
Fixtures, tool lists and verified CAM programmes are retained for the life of the part number, so a repeat release runs on the same setup as the first batch without a new proving run.
Send the drawing or the 3D model for a quotation. Include material, quantity, tolerance and finish, and a detailed quote with lead time is returned within one working day.
