Step 1: measure what you buy in
Pull twelve months of purchase invoices for spiral duct and round fittings. Sort them by diameter and gauge and add up the metres, the elbows and reducers, and the money. Then add what the invoices do not show: the jobs you lost or delayed because round duct was on someone else’s schedule, and the margin you gave away by reselling. Shops that buy in more than roughly 1,500–2,000 metres of spiral a year, or that have been caught by a supplier’s lead time twice, usually find a compact tubeformer pays back inside two years on the resale margin alone; our payback calculator lets you put your own numbers in. Below that volume, keep buying in unless a specific contract changes the picture.
Step 2: pick the machine class
| Volume and work | Machine class | Taokron example | Why |
|---|
| Occasional round duct, one project at a time, mostly Ø100–800 mm in 0.5–0.8 mm | Compact saw-blade tubeformer | SBTF-1500: Ø80–1500 mm, 0.4–1.2 mm, 5.5 kW + 4 kW saw, 1,708 kg | Lowest capital and floor; saw cutting is simpler to maintain; enough for part-time production |
| Daily round duct, full diameter range, commercial gauges | 1602-class flying-slitter tubeformer | SBTF-1602: Ø80–1600 mm, galv 0.4–1.3 mm, SS 0.4–0.8 mm, 11 kW | The industry standard class; clean slitter cuts at speed; stainless capability for kitchen exhaust |
| Mining, industrial exhaust, jacketing, duct above Ø1600 mm or above 1.3 mm | 2020-class heavy-gauge tubeformer | SBTF-2020: Ø80–2500 mm, 0.4–2.0 mm, plasma + slitter, 22 kW | Only if the heavy work exists; it is a bigger machine to feed and house |
Brand and product names are the property of their respective owners, referenced here for honest comparison only. Ownership, positioning and published ranges are as verified in September 2026 from each maker’s own publications; confirm current specifications and support with each vendor before buying.
Buy the class for the work you actually invoiced, not the biggest diameter you can imagine. A rectangular shop’s first tubeformer is very often the compact machine, replaced or joined by a 1602-class machine two or three years later when round duct has become a product line rather than a favour. Our spiral tubeformer comparison shows what other makers publish in each class.
Step 3: budget the fittings line
A tubeformer makes straight pipe; customers buy systems. On day one you need a way to make elbows and reducers, and it is usually the fittings, not the pipe, that a buying-in shop struggles to source quickly. The minimum set: a fitting shaper for reducers, saddles and take-offs (Ø90–400 mm covers most rectangular shops’ round work), and either an elbow welder for pressed small elbows (Ø80–250 mm) or gored segments cut on the plasma table you already own and closed on a stitch welder. Add a flanging machine when flanged joints are specified, and an ovalizer only when flat-oval work appears. Our fittings machines comparison maps the options.
Step 4: floor, power, coil and people
- Floor. A compact machine needs about 3.4 × 2.1 m plus a run-out for 3 m ducts and coil access; a 1602-class machine about 2 × 1.7 m mainframe, a 2 × 1.1 m decoiler and a 2.5 m run-out table. Long tubes need a longer run-out.
- Power and water. A dedicated three-phase circuit (5.5 + 4 kW compact, 11 kW 1602-class) and, for a flying slitter, a small cooling-water supply.
- Coil. Spiral machines run slit strip, 137 mm for 0.4–1.0 mm and 140 mm for 1.1–1.3 mm. Confirm your coil supplier slits to those widths or budget a slitting machine.
- Heads. Forming heads are diameter-specific; buy the set for the diameters in your invoices and add heads as work appears.
- People. One operator trained at commissioning; a spiral machine is not hard to run, but head changes and strip tension want one person who owns them.
Step 5: acceptance test and start-up
Have the machine run on your slit coil at your top three diameters at the factory, timed and measured, and test-fit the sample to spiral duct you have bought in; put it in the factory acceptance test. Plan the first month’s round-duct jobs from the purchase history you pulled in step one, so the machine starts on work you already know you sell. Commissioning is two to three days for a tubeformer with fittings machines; see installation and commissioning.
The worked path Taokron recommends
This is our own recommendation, so read it as a vendor’s. Taokron is an Australian supplier that has built HVAC duct machinery since 1995, with 5,000+ machines in 100+ countries, and most of our spiral machines go into shops that already run our rectangular lines. The path we see work: an SBTF-1500 with a fitting shaper and elbow welder in year one, using the shop’s existing plasma table and welders for gored elbows; an SBTF-1602 when round duct passes about a third of the shop’s output, keeping the 1500 for overflow or small diameters; a flanging machine and ovalizer as the specifications demand them. Because the round and rectangular machines come from one vendor, one engineer commissions the addition and one spares list covers the shop. Weigh: if your round-duct volume is already high and the money is there, skip the compact step and buy the 1602 class; our Spiro 1602 versus SBTF-1602 page shows where the benchmark machine is the better buy.
Ask for a round-duct start-up quotation with your purchase history →
FAQ
How much spiral duct do I need to buy in before making it pays?
As a rule of thumb, shops buying in more than about 1,500 to 2,000 metres a year, or that have been caught by supplier lead times twice, find a compact tubeformer pays back inside two years on resale margin alone. Put your own invoices into the payback calculator; the answer depends on your margin and your supplier’s prices.
Should my first spiral machine be the compact one or the 1602 class?
If round duct is occasional, the compact saw-blade machine (Taokron SBTF-1500) costs least in capital, floor and maintenance. If you will run it daily across the full diameter range, or need stainless for kitchen exhaust, buy the 1602 class from the start.
What fittings machines do I need on day one?
A fitting shaper for reducers and take-offs, and a way to make elbows: an elbow welder for pressed small elbows, or plasma-cut gores closed on a stitch welder. Flanging and ovalising machines come later as specifications demand.
What coil does a spiral machine use?
Slit strip, typically 137 mm wide for 0.4 to 1.0 mm and 140 mm for 1.1 to 1.3 mm. Confirm your coil supplier slits to those widths or add a slitting machine.
How long does it take to be producing?
Two to three days of commissioning for a tubeformer with fittings machines on a prepared site, after a factory acceptance test on your own strip. Plan the first month’s jobs from your purchase history so the machine starts on known work.
Can I keep buying in the large diameters?
Yes, and many shops do: make the diameters that dominate your invoices and buy in the occasional large ones until the volume justifies the heads or a bigger machine.
