What each material genuinely does

Hardwood — usually maple or beech — is dense and internally damping. It absorbs vibration, which is why hardwood machines tend to sound quieter even with identical bearings. It is also heavy, typically 100–140 lb, and it responds to humidity: in a very dry or very damp room, joinery can move slightly over years.

Anodized aluminum is dimensionally stable regardless of humidity, lighter at roughly 70–95 lb, and does not need refinishing. It transmits more vibration, so aluminum machines depend more heavily on good bearings to stay quiet, and the anodized finish resists sweat and cleaning products well.

Frame material comparison
HardwoodAluminum
Typical weight100–140 lb70–95 lb
Vibration dampingHigher — quieter for equal bearingsLower — depends on bearing quality
Humidity stabilityMoves slightly over yearsUnaffected
Moving and stackingDifficultPractical
RefinishingPossibleNot needed
Best suited toPermanent studio installationHome, mobile, multi-use rooms

The question that actually decides it

Will the machine move? If it will live in one place for a decade, hardwood is a pleasure and its weight is an advantage — it simply does not shift. If it will be folded, stacked, moved between rooms or carried to clients, aluminum turns a two-person job into a one-person job.

Almost every other consideration people raise — appearance, longevity, feel — is decided by build quality rather than material.

What to check regardless of material

Look at the joints, not the surface. On hardwood, that means how the rails meet the uprights and whether the joinery is mechanical or only glued and screwed. On aluminum, it means whether corners are welded or bolted, and how thick the extrusion wall is.

A thin, bolted aluminum frame and a poorly jointed hardwood one will both develop play. A well-made example of either will not.

How each ages over a decade

A hardwood frame in a humidity-stable room is essentially unchanged at ten years, and can be sanded and resealed to look new. In a room that swings between very dry winters and humid summers, joints loosen gradually and the frame eventually racks — a failure that cannot be economically corrected.

An anodized aluminum frame is dimensionally unchanged regardless of the room. What ages on it is the appearance of the fittings rather than the structure, and no refinishing is possible or needed.

Noise, in practice rather than theory

Hardwood damps vibration better, so with identical bearings a timber machine sounds slightly quieter. In practice the difference between a good and a poor bearing is several times larger than the difference between the two frame materials.

If quiet operation is the priority — a room above a bedroom, a shared building — spend the attention on bearing type and rail finish rather than on frame material.

What actually determines carriage noise
FactorEffect on noiseCan it be fixed later?
Bearing typeLargest single factorOnly by replacing wheels
Rail finish and conditionLargeNo, once scored
Frame materialSmallNo
Wheel materialModerateYes
Floor and mat under frameModerateYes, easily

The decision in one question

Will the machine move? If it will live in one place for a decade in a climate-stable room, hardwood is a pleasure and its weight is an asset. If it will be folded, stacked, carried between rooms, or kept in a garage or coastal property, aluminum removes most of the risk and half the weight.

Everything else people raise — appearance, longevity, feel — is decided by build quality within each material rather than by the choice between them.