Billet means the part was machined out of a solid block of aluminium rather than cast in a mould or printed layer by layer. On a car part the word tells you two things: the metal is a wrought alloy with the same properties all the way through, and the shape came off a CNC machine, so the dimensions are tight. I have just finished drawing the first three billet parts for the FG Falcon, so this is what the word means in practice, and when it is actually worth paying for.
Billet vs cast vs 3D printed: what is the difference?
There are three common ways to make a small metal or plastic part for a car, and the word on the listing tells you which one you are getting.
Cast means molten aluminium poured or injected into a mould. It is the cheapest way to make a complex shape at volume, which is why a lot of factory parts are cast. The downside is porosity, small voids inside the metal, and casting alloys are generally softer than wrought ones. For a bracket that never gets touched, none of that matters. For something you grip or thread every week it can.
Billet means the part starts as a length of extruded or rolled aluminium bar, already heat treated, and a CNC machine cuts away everything that is not the part. There is no porosity because the metal was never liquid in the mould. Tolerances come down to the machine, not the shrinkage of a casting. The trade off is cost: machine time is expensive and a lot of the original bar ends up as swarf.
3D printed usually means plastic, printed in layers. It is brilliant for prototyping, I use it for exactly that, but it is a poor material for a finished interior part in this country. PLA, the most common printing plastic, starts to soften at around 60 degrees Celsius, and a closed car in a Perth summer gets there easily. Layer lines also show, and no amount of sanding makes a printed part feel like it came with the car.
What is 6061-T6 and why does it matter?
All three FG billet parts are machined from 6061-T6. The 6061 is the alloy, aluminium with magnesium and silicon, and the T6 is the heat treatment: solution treated, quenched and artificially aged, which is what gives it its strength. It machines cleanly, it anodises evenly, and it does not corrode easily, which is the combination you want for an interior or engine bay part.
You will see 7075 on some billet parts. It is stronger, but it costs more and it does not take anodising as consistently. For an oil cap, a shift knob or a cupholder divider, none of them are structural, so 6061-T6 is the right material, not the budget one.
Is billet actually stronger than cast?
Generally yes, but for the parts we are talking about strength is close to irrelevant. Nobody is going to snap an oil cap. What billet buys you on a part like this is dimensional accuracy, a consistent finish, and no voids that open up when you cut a thread or a groove into the part. That last one matters more than people think. A cast part machined for a thread can expose porosity right where you need a clean seal.
What does anodising do, and does it wear off?
Anodising is not paint. It is an electrochemical process that grows the natural oxide layer on the aluminium into something much thicker and harder, and if the part is coloured, the dye is locked into that layer before it is sealed. Because it is part of the metal rather than sitting on top of it, it does not chip or peel the way a painted or powder coated finish can.
It is not completely immune to the sun. Strong colours, reds and purples especially, can fade over years of direct UV. Black and clear anodising hold up best. An oil cap lives under a bonnet, so it is protected. A shift knob sits in the sun all day, which is one reason the shift knob finishes are brushed and brushed black, not bright colours.
Raw or brushed aluminium with no anodising is a different story. It is uncoated, so it will dull and pick up marks with use, and a wipe with metal polish brings it back. If you want a finish that stays the same for years, choose anodised.
Where billet beats carbon fibre on an FG, and where it does not
RB Innovations started with carbon, and carbon is still the right call for anything that is a shape over a surface: the shifter surround, the coil cover, the door pull cups. Carbon is light, it covers a large area, and the weave is the whole point. If you want the background on how it stacks up against other materials, I wrote up carbon fibre vs fibreglass vs ABS for car parts earlier this year.
Billet is for the things you grab, twist or thread. A shift knob needs weight in the hand and a thread that will not strip. An oil cap needs a seal face that is dead flat. A cupholder divider needs to sit in a hot cabin for ten years without changing shape. None of those are carbon jobs.
The three FG billet parts, and what I learnt drawing them
Each of these was designed in Australia from measurements and scans of the actual car, and each one taught me something I did not know before I started.
Barra billet oil filler cap
Before I drew the Barra billet oil filler cap I measured the filler neck on my own rocker cover: 33 mm across the thread crest, 36 mm at the widest point, with a coarse single start thread. I then printed a set of plastic test coupons at slightly different thread sizes and screwed each one on until I found the one that seated properly. That is what 3D printing is good for. Only after that did the design go to metal.
The cap reuses the flat rubber seal off your factory cap, so there is nothing else to buy, and the five scallops around the edge are there so you can get it off with oily hands. The logo is machined into the face rather than printed on, so it cannot wear off. It suits the Barra 4.0L in BA, BF, FG and FG X Falcons and SX, SY and SZ Territorys, in black or clear at $69 and red, blue, purple or orange at $79. The first batch is in production. Engine bay heat is a question I get asked about carbon, and the answer for aluminium is simpler: it does not care. If you are curious about the carbon side, see does engine bay heat damage carbon fibre parts.
FG and FG-X billet manual shift knob
The reason the FG billet manual shift knob exists is that Ford never sold the knob on its own. If your factory leather is split, the only genuine fix is a complete new old stock shifter assembly, and those are over $600 and running out. So I drew a replacement to the same shape and size: one piece of 6061-T6, no pressed rings or glued collars, wrapped in black Nappa leather with medium grey stitching to match the original.
Two details came out of doing it properly. The thread is M12 x 1.5, confirmed on 2008 onward cars, so it winds straight onto the factory lever with no adaptor. And the knob gets very hot sitting in direct sun, hot enough that an ordinary adhesive under the leather would eventually let go, so the leather tucks into machined grooves under the top ring and collar rather than relying on glue alone, and the adhesive had to be specified for that heat. The top pocket takes a 33 mm gel dome badge, which is not included, so you can run whichever badge suits your car. Brushed is $229 and brushed black anodised is $239, and the first run is in production.
FG and FG-X billet cupholder divider
The FG cupholder is one open tray from the factory, so a quick corner tips your drink. The FG billet cupholder divider drops into the middle by hand, no tools, and holds each cup in its own pocket. There is a pocket machined into the underside to keep the weight down, and it was test fitted in the car so it sits firm without rattling.
This one works differently to the others. It is a group batch: pre-orders open on 2 December and close on 16 December 2026, the batch only goes ahead if at least 20 are ordered across both finishes, and if it falls short everyone is refunded in full. Dispatch is late January 2027. Raw machined is $79 and gloss black anodised is $89.
Plastic interior parts on the FG are also why the FG Falcon door pulls crack in the first place, which is a useful reminder of what a hot cabin does to the wrong material over fifteen years.
When is billet worth paying for?
Pay for billet when the part is handled, threaded or sealed, when it lives somewhere hot, or when a cast or printed version would look out of place against factory trim. Do not pay for it on a hidden bracket where a casting does the same job. On an FG the obvious billet candidates are exactly the ones above: the cap you twist every oil change, the knob you hold every drive, and the divider that sits in the sun.
If you are ready to look at the actual parts, the full range of Ford Falcon FG and FG-X billet and carbon fibre parts is in one place, and everything else we make is in the complete RB Innovations catalogue.
FAQ
Is billet aluminium better than cast aluminium?
For strength and consistency, yes. Billet starts as heat treated wrought bar with no porosity, so threads and seal faces machine cleanly. Cast is cheaper at volume and fine for parts that are never handled or threaded. For small parts you touch or seal, billet is the better material.
Does anodising wear off?
Not in the way paint does. Anodising is a hardened layer grown into the aluminium itself, so it will not chip or peel. Bright dyed colours can fade after years of direct sun. Black and clear anodising hold their look the longest.
Will a raw aluminium part corrode or dull?
6061-T6 does not rust, but an uncoated raw or brushed surface will dull and can pick up marks with handling. A wipe with metal polish restores it. If you would rather not maintain it, choose an anodised finish.
Does a billet shift knob get hot in the sun?
Yes. Aluminium conducts heat, and a knob in direct sun gets very hot, the same as the factory aluminium knob always did. The leather wrap is what you hold, and on the RB Innovations knob the leather is held in machined grooves with a heat rated adhesive for exactly that reason.
Why not just 3D print an FG cupholder divider?
You can, and for a test fit I would. As a finished part, PLA starts to soften at around 60 degrees Celsius, which a closed car reaches in summer, so printed dividers can warp, and the layer lines always show. A machined aluminium divider will not move in the heat and looks like it belongs in the car.
Riley Baginski, founder, RB Innovations.
