Jiggers look simple. Two cups, one seam, a few lines stamped inside. The moment a customer asks for four measurement marks instead of two, the job stops being simple — geometry starts calling the shots. Here is a real case from our floor: a buyer wanted 1 cl, 2 cl, 3 cl and 4 cl marked inside a stainless steel jigger. Three we could make. One we could not, and the reason is worth writing down because it comes up on almost every custom jigger project.
The Request: Four Marks Inside One Cup
The brief was a double-ended jigger in 304 stainless steel, with four graduated marks — 1 cl, 2 cl, 3 cl and 4 cl — on the inside of the small cup. On paper it is four lines. In practice, the 1 cl mark sits roughly 4 mm above the inside floor of the cup, which is exactly where the drawing radius turns into the base. That is the hardest place on the whole tool to work.
Two problems showed up immediately. The first is access: the cavity is narrow and deep, and whatever makes the mark — an etching electrode, a laser head, a stamping punch — has to reach past the rim without touching the wall. The second is readability: a line sitting that close to the floor is hidden by the liquid itself the moment you pour, and by the shadow of the cup wall when you look down into it.
Why the 1 cl Line Could Not Be Made
We ran it both ways before answering. A stamped mark needs a punch that bottoms out against the inside floor; at 1 cl there is not enough clearance for the punch body, and forcing it leaves a burr that catches a cloth and will not pass a food-contact check. Chemical etching needs a mask that lies flat against the surface; at the base radius it will not, so the line comes out uneven and half the depth it should be.
Even where we can make a mark that low, we usually advise against it. Our own rule of thumb is a minimum of 4.5 mm from the inside floor to the first graduation, and at least 4 mm between any two graduations. Below that, the bartender is guessing rather than reading — and a measurement mark that cannot be read is worse than no mark at all, because people trust it.
How Internal Scales Are Actually Made
There are three processes in normal use, and each one suits a different cup geometry:
Chemical etching — a resist is applied, the exposed metal is dissolved with acid, and the line is a shallow recess. It is the cheapest option at volume, it takes colour fill well, and the depth is consistent. It needs a surface the mask can seal against, which rules out tight base radii.
Laser marking — the surface is annealed or lightly ablated, leaving a dark line with no material removed. It holds tight tolerances and reads well on curved walls, but the mark sits almost flush with the surface, so it wears faster under steel wool and commercial dishwasher cycles.
Stamping or rolling — a punch presses the line into the wall. It is the most durable and gives a crisp edge that catches the light, but it needs clearance for the tool and it displaces metal, so the wall has to be thick enough to absorb it without distorting.
Etched vs Laser vs Stamped: Picking the Right Process
| Process | Durability | Best for | Watch out for |
|---|---|---|---|
| Chemical etching | Good — recessed, takes colour fill | Straight or gently tapered walls, runs above 1,000 pcs | Will not seal against tight base radii; uneven depth near the floor |
| Laser marking | Fair — flush with the surface | Curved walls, tight tolerances, small runs | Fades under abrasive scouring and harsh dishwasher detergent |
| Stamping / rolling | Best — displaced metal, crisp edge | High-volume standard jiggers, thick-wall cups | Needs tool clearance; not possible close to the inside floor |
What We Shipped Instead
We explained the geometry to the customer and sent both a drawing and a photo of a trial cup so the problem was visible rather than theoretical. They understood and agreed to drop the 1 cl graduation. The production sample carries 2 cl, 3 cl and 4 cl inside the small cup, all sitting comfortably above the base radius and spaced evenly enough to read at a glance.
Sampling took 10–14 days including the trial etch, and the sample went out with an AQL 2.5 inspection report. The customer was happy with the finish and placed the order. If you genuinely need a 1 cl measure on the bar, the honest answer is a smaller jigger or a separate graduated measure — not a line pressed into the bottom of a cup. Tell us the graduations you need and the cup volume you are working with, and we will tell you which of them the geometry can carry before you pay for tooling.
