Amada Coma 555
Turret Sleeving

Amada Coma 555 at a glance

Era

1978

Tonnage

50-55 ton

Stations

44/2AI, 58/2AI or 72

Turret

Thick turret

Auto-Index

2 A/I

Control

Fanuc 6M

The Coma line ran from the 1970s to 1994 and is long out of production. These are heavily built machines and a great many are still in daily service, which is precisely why turret restoration matters on them — there is no factory-fresh replacement to buy.

Where this machine is in its life

A Coma 555 built in 1978 has been earning for three decades or more. Machines of this generation are usually fully depreciated, well understood by the people running them, and producing perfectly acceptable work — right up until turret wear starts showing in the parts.

That is the decision point most Coma owners reach. The mechanical structure of these machines is heavily built and typically still sound; what has aged is the turret bores, and often the control. Neither requires replacing the machine.

How a Coma 555 turret wears

At 50 tons, the Coma 555 is in the heavy class, and that changes how the turret wears. Every stroke puts substantial force through the station bore. Wear here is driven by load rather than cycle count, and it tends to show first in the stations carrying the largest tools on the thickest material.

With 44/2AI, 58/2AI or 72 stations, work is spread across a wide turret, which is why wear on these machines is so rarely uniform. In practice a handful of stations carry the common tools and wear out well ahead of the rest. Most Coma 555 jobs are partial as a result — the worn stations are sleeved and the sound ones are left alone, which keeps both cost and downtime down.

The tell is always the same: the fault stays with the station rather than following the tool. Move a tool that is producing bad parts to another station — if it runs clean there, the bore is worn, and new tooling will not change that. See holes out of round, burring on punched parts or punches dulling too fast for the full diagnosis.

What sleeving a Coma 555 involves

Each worn bore is machined to a precise oversize and a hardened USA-made steel sleeve is installed with a precision slip fit and secured with retaining compound, restoring the station to Amada factory tolerance — typically within 0.0002″. Engineers travel to you; the Coma 555 never ships. 2–3 days of downtime, typically $8,000–$25,000 depending on scope. After the first install your own maintenance staff can replace sleeves in future.

Set against $100,000–$500,000+ for a replacement machine — see sleeve or replace, including where replacing genuinely wins.

2 A/I on this machine

The Coma 555 carries 2 A/I. Auto-index stations rotate tooling in 0.01° increments through gears, bearings and a rotary encoder mechanism — all in constant motion, all wearing. Symptoms are angular drift, indexing errors, alarm codes and parts punched off-angle.

TSI rebuilds them completely and calibrates before sign-off, routinely in the same visit as sleeving. Auto-index refurbishment · diagnosing angle errors.

Is the Coma 555 a thick or thin turret machine?

The Coma 555 is a thick turret machine. Thick and thin describe the turret, not automatically the tooling — the two are quoted separately, and a machine has to be identified on both counts before sleeves or tooling are ordered.

Tonnage will not tell you either: several 22-ton Amada machines run thick turrets. If you are not certain what your press carries, send us the model and serial number and we will confirm it. See also thick vs thin turret and how Amada model numbers work.

Turret configurations for the Coma 555

The Coma 555 was not built with one turret. Amada offered more than one layout, so the station count does not follow from the model name — it has to be read off the machine. These are the configurations documented for this model:

A–E are Amada tool-station sizes: A ½″, B 1¼″, C 2″, D 3½″, E 4½″. A blank size column means the station and auto-index totals are confirmed but the factory A–E mix is not — we would rather leave it open than guess it.

Confirm before you quote. Because the Coma 555 exists in more than one layout, we verify the turret from the serial number or a photograph before pricing any sleeving. If you send us the serial number we will tell you which of the above you have, and how many stations that means. Send us the serial number.

Station layouts documented for the Coma 555

The Coma 555 is documented on 2 different turret layouts — which is exactly why the station count has to be read off the machine instead of assumed from the model number. Both are drawn below, so you can tell at a glance which one you are looking at.

Bore positions, bore sizes and the numbering are read from the Amada factory layout sheet. Stations are grouped, not evenly spaced — that grouping is real, and it is the quickest way to recognise your turret. Follow a link for that turret's full station list.

What the number tells you

Amada model numbers describe the machine. The Coma 555 decodes as a 50-ton class press with a 50 × 50 table — the first digit is tonnage, the other two are table width and length. Its full designation is COMA-505050.

How to read an Amada model number — useful when your paperwork and your badge disagree.

How the Coma 555 compares

The original Coma, also sold as the NCT 555; the 72-station turret is on the early machines — that is what sets this machine apart on the spec sheet.

These machines are easy to mix up, and the difference matters when you are quoting a turret job. Against the other Coma models we cover:

• Amada Coma 567 — stations 44, 58 or 72 · auto-index 2 A/I · tonnage 50-55 ton.
• Amada Coma 557 — stations 44/2AI, 58/2AI or 72 · auto-index 2 A/I · tonnage 50-55 ton.
• Amada Coma 588 — stations 44 or 58 · auto-index 2 A/I standard; 4 A/I also built · tonnage 50 ton.

Sleeving is the same process across all of them. What changes is scope, and scope follows station count and how hard the machine has been run.

The Fanuc 6M control

A Coma 555 of this vintage shipped with the Fanuc 6M. If yours is still original, it is very likely the oldest thing on the machine — and the part most likely to strand it, because a control fault on an obsolete system is harder to solve than any mechanical wear.

TSI performs FANUC-based retrofits that keep full programming compatibility, so existing programs continue to run unmodified. Done in the same visit as turret work, it is one shutdown rather than two. See control upgrades.