What We Check on the Jig Table Before Your Aluminium Kit Leaves the Workshop
A transparent pre-dispatch QC checklist for trade aluminium fabrication — dimensions, hardware, weatherseals, glazing and labelling. Use it to evaluate any fabricator, or to understand what happens to your order before it reaches site.
Every installer has unpacked a kit on site and thought: this should have been caught before it left the factory.
We publish this checklist so you know exactly what happens to your order on our jig table in Warrington — and so you have a benchmark when you are comparing fabricators. If a supplier cannot describe their pre-dispatch checks this specifically, assume your fitter will absorb the gaps.
This is the process behind our 99% first-time fit rate. For the commercial argument — why jig testing protects margin versus cut-and-ship suppliers — read why jig-tested aluminium kits fit first time.
Stage 1 — Documentation lock
Before any unit reaches the jig, manufacture only starts against confirmed specification:
- Signed CAD or approved quote dimensions
- Hardware schedule (lock type, closer, pivot/floor spring, panic hardware, access control prep)
- Threshold type and hand of door
- Glass spec and finish (RAL reference)
- Opening reference label assigned
No confirmed spec, no cut. This prevents the workshop building to an ambiguous email thread.
Stage 2 — Dimensional verification on the jig
The fabricated frame or leaf is placed on the jig table and checked against the confirmed sizes:
| Check | What we verify | Typical failure mode if skipped |
|---|---|---|
| Width (head and threshold) | Matches signed CAD within workshop tolerance | Leaf binds or shows uneven reveal |
| Height (both jambs) | Square and parallel | Diagonal twist — door drags at top or bottom |
| Diagonals | Frame square | Corner gasket gaps, closer misalignment |
| Frame depth | Profile sits correctly in rebate | Fixings pull frame out of true |
| Threshold position | Correct type fitted (100mm / 150mm / drained) | Water ingress or trip hazard |
On replacement work, the survey dimensions are the authority — not an assumed standard size from a catalogue.
Stage 3 — Hardware operation
Hardware is cycled on the jig before dispatch:
- Hinges / pivots — full arc, no binding, correct backset
- Floor springs / closers — opening and closing force checked; hold-open and latch points verified
- Locks and panic hardware — engagement tested; cylinder orientation confirmed
- Access control prep — strike plate positions and conduit routes where specified
- Window operators — tilt, turn and restrictor functions on TW70/SW60 units
Hardware faults discovered on site cost a return visit. Hardware faults discovered on the jig cost us a workshop hour.
Stage 4 — Weatherseals and glazing
Where the product includes glazing and beading in our workshop:
- Gaskets seated consistently — no gaps at corners or transom junctions
- Beads clipped and secure — external beading checked on shopfront and entrance products
- Drainage paths clear on drained thresholds
- Glass alignment and pocket clearance within system limits (per Jack Aluminium system tolerances)
- Manifestation or safety glazing markers where specified
Factory glazing is not universal across every product line, but where we bead in Warrington, it is checked on the jig — not assumed.
Stage 5 — Finish and presentation
- Powder coat inspected for handling damage, exposed metal and face consistency
- Protective film applied where required for transit
- Opening reference label applied — matches your schedule and PO
- Kit completeness check — beads, gaskets, fixings, packers and specified hardware in the box
A missing gasket strip is a 45-minute site delay. The completeness check happens before wrap, not after your fitter calls.
Stage 6 — Pass / fail gate
Pass: Unit matches signed specification. Labelled, wrapped, palletised for dispatch.
Fail: Any dimensional, hardware or completeness issue. Unit stays in the workshop for remake or adjustment. We do not dispatch and hope the installer will “make it work.”
That pass/fail gate is what separates jig-tested supply from cut-and-ship. Most fabrication callbacks we hear about from installers joining us from other suppliers trace back to suppliers who skip this gate.
How this differs on reactive replacement orders
Reactive jobs often run from survey rather than architect CAD. The jig table check is the same — but the input is your survey package:
- Outerframe and leaf sizes from the maintenance survey
- Photos of the failed unit for hardware and threshold identification
- Like-for-like or upgrade confirmation in writing
See replacing a failed commercial aluminium door for the survey fields that make jig testing reliable on reactive work.
What you should expect when the kit arrives
When jig testing has been done properly, your installer should experience:
- Unpack — labelled by opening reference
- Offer into opening — frame sits without packing or grinding
- Fix — standard fixings, no improvisation
- Commission hardware — adjust closer speed if needed, not remake head detail
- Hand over — no callback for fabrication error
If step 2 fails routinely from a supplier, the problem is upstream — not your fitter.
That is also why a jig-tested kit may quote slightly higher than cut-and-ship alternatives. Standing the frame in the workshop, running hardware, checking seals and confirming completeness before wrap is real labour — labour most fabricators skip to win on unit price. Our trade clients accept that premium because the kit arrives ready to work, not ready to argue about. Read why jig-tested kits fit first time for the full commercial case.
Use this checklist in supplier reviews
When you are evaluating or switching fabricator, ask to see their QC process described at this level of detail. Generic claims like “quality assured” or “ISO certified” (if they even have it) do not tell you whether your door was checked before dispatch.
Send us a test opening through quick quote and ask us to walk you through the CAD sign-off and jig-test stages on that specific order. That is the practical proof — not a brochure claim.
We manufacture in Warrington, deliver palletised kits throughout mainland Britain via trade delivery, and aim for 21-day standard lead time from confirmed order. The jig test is what makes the lead time worth waiting for.