Linkage arms
Matched pair — the reason five-axis matters is that the bore axes must agree between them.
CNC Milled & Structural Components
Three-, four- and five-axis milled parts — from small clamp blocks in repeat quantities to large structural housings and long frame rails where flatness across the whole part is the specification.
- Aluminum, steel, PEEK and engineering plastics
- Five-axis work on organic and compound-angle geometry
- Thin-wall and lightweighted parts held flat through the cut
Where milling gets difficult
Almost none of the difficulty in these parts is in removing the metal. It is in the part staying where you put it. A long frame rail relieves internal stress as it is cut and bows; a thin-wall plate flexes away from the cutter and springs back afterwards; a five-axis housing needs its bores concentric across faces that are never presented to the spindle in the same orientation.
So the work is in fixturing, cut sequence and stress relief between roughing and finishing — decisions that are invisible in the finished part and are most of what separates one made right from one made once. Where a drawing asks for something that will fight the process, we say so at DFM review rather than after the first article.
Five-axis and structural parts
Compound-angle and organic geometry, where the datum has to hold across faces the spindle sees from different directions.
Polished triple clamp
Clamped tube seats bored parallel, then the outside polished.
Structural frames
Compound-angle faces and pockets on both sides.
Connecting rods
Bore-to-bore centre distance is the dimension that matters here.
Frame rails, plates and large parts
Long and large components where the tolerance is not on any single feature but on flatness and hole position across the whole envelope.
Long frame rails
Stress-relieved between roughing and finishing so they stay straight.
Frame detail
Pocket floors and bored seats on a single reference.
Channelled cover plates
Internal channels and a seal groove that has to stay flat under bolt load.
Spoked ring frame
Large diameter, thin radial webs — supported through the cut so it doesn't chatter.
Thin-wall and lightweighted parts
Plates taken down to the minimum section that still carries load. The limit is not the cutter, but how much the part deflects during cutting and relaxes or distorts after unclamping.
Skeletonized plate
Long slots and thin webs, anodized black after machining.
Lightweighted plate set
A family of plates lightened to different degrees from the same stock.
Thin-wall group
Production group, where flatness has to repeat part to part.
Brackets, blocks and clamp hardware
Smaller milled parts in repeat quantities. The engineering question shifts from 'can it be made' to 'does part 500 measure the same as part 1'.
Milled brackets
Slotted and stepped brackets machined as a matched pair.
Twin-bore brackets
Forked brackets where both bores must share an axis.
Clamp block batch
Eight identical parts — the point of the photo is that they are identical.
Split clamp bushings
Slit after boring, so the bore is round before it is relieved.
Beyond aluminum: steel, PEEK and engineering plastics
Not every part should be aluminum. PEEK where the part must be electrically or thermally isolating and dimensionally stable, POM where it has to slide, steel where it has to take load or wear.
PEEK plate
Machined PEEK — low cutting forces, but it moves with temperature and moisture.
PEEK blocks
Tapped and counterbored PEEK for insulating mounts.
PEEK arc segment
Curved profile machined from solid rather than formed.
POM blocks
Acetal carriers where the part has to slide, not grip.
Steel mounting plates
Milled steel plate with apertures and countersinks.
Steel hinge plates
Stepped and bored, in matched sets.
Timing pulley
Cut tooth form with a bored and keyed hub.
Pinion gear
Cut gear teeth on a machined blank.
What we hold on milled work
Routine figures for the part families above, not the tightest achievable. Which feature actually controls the assembly matters more than the tightest number on the drawing.
Linear tolerance
±0.02 mm on machined features as a normal expectation, tightening per feature where a fit depends on it.
Flatness
Held across the whole envelope rather than locally, which on long rails means stress relief between roughing and finishing — not a final skim.
Five-axis positioning
Bores and faces that must agree across orientations are cut without re-fixturing, so their relationship comes from the machine rather than from a setup.
Thin-wall sections
Down to around 0.8 mm in aluminum depending on span and geometry. Below that the achievable tolerance is set by springback, so we quote it per part.
Wall thickness, span and material all interact — a 1 mm wall over 20 mm behaves nothing like 1 mm over 200 mm. Send the geometry and we will tell you what will hold its shape rather than quoting a single number.
Frequently Asked Questions
How thin a wall can you machine?
In aluminum, down to roughly 0.8 mm depending on how far it spans and what supports it. The honest answer is that wall thickness on its own does not determine feasibility: a 1 mm wall 20 mm across is straightforward, the same wall over 200 mm will deflect under the cutter and spring back afterwards. Send the geometry and we will tell you what will hold its shape, and where adding a rib would cost less than tightening a tolerance.
Do you have five-axis capability, and when does it actually matter?
Yes. It matters when features on different faces have to agree with each other — bore axes that must be parallel, or a compound angle referenced to a datum on another face. Cutting those in one orientation removes the setup error entirely. For a part that is essentially prismatic, three-axis work in two setups is often cheaper and just as accurate, and we will say so rather than quoting the more expensive route.
How do you stop long parts bowing?
By cutting them in stages. Stock carries internal stress, and removing material unevenly lets it move — so a long rail roughed to shape and then finished in the same setup will come off straight and bow later. We rough, allow the part to relieve, then finish, and fixture so clamping is not itself inducing the distortion. This is why a long frame rail costs more per hour of cutting than its shape suggests.
Can you machine PEEK and engineering plastics?
Yes — PEEK, POM and similar. They cut easily but hold tolerance differently from metal: PEEK moves noticeably with temperature and, over time, with moisture, so a dimension measured warm off the machine is not the dimension you will receive. We let parts stabilise before final inspection. If your tolerance is tight enough for that to matter, tell us the service temperature and we will discuss whether the material can actually hold it.
Can you cut gears and toothed profiles?
We machine cut tooth forms — timing pulleys and pinions like those shown above — on machined blanks. For high-volume or high-precision gearing to a specific AGMA or DIN quality class, tell us the class you need up front, because that is a different process question from simply cutting a tooth profile and we would rather establish it before quoting.
What size envelope can you machine?
The parts on this page run from clamp blocks a few centimetres across to structural housings and frame rails several hundred millimetres long. Rather than publish an envelope that may not match your part's real constraint, send the overall dimensions and we will confirm — for large parts the limiting factor is often the fixturing and the reach needed for a specific feature, not the table size.
Have a milled part to quote?
Send your STEP file and drawing with the material, quantity, critical tolerances and which datum features control the assembly. We will review it for manufacturability and come back with a quotation.
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