Choosing a Bar Bending Machine by Bar Diameter: GW42, JBB42A or GW50
Quick answer
Choose a bar bending machine by the largest bar diameter in your bar bending schedule. If nothing goes above 32 mm, the GW42 or the JBB42A is the right machine. If even one bar mark calls for 36 mm or 40 mm, you need the GW50. Between the GW42 and the JBB42A the bending capacity is identical; the choice is about how the machine is driven. The JBB42A adds automatic and manual bending from the foot paddle and a heavy-duty control panel, which pays off on long runs of identical shapes.
All three are electric bench benders built by Jamshedji Constro Equip at MIDC Bhosari, Pune. They look alike in photographs because they share the same general construction, so this guide sets out what actually separates them: bar capacity, motor, control and weight, and which one fits which kind of site.
The three machines
GW42 vs JBB42A vs GW50 at a glance
| Specification | GW42 | JBB42A | GW50 |
|---|---|---|---|
| Bar capacity (TMT) | 6–32 mm | 6–32 mm | 6–40 mm |
| Motor | 3 kW / 4 HP, 1440 rpm | 3 kW / 4 HP, 1440 rpm | 5 kW / 6.5 HP, 1440 rpm |
| Power supply | 415 V, three-phase | 415 V, three-phase | 415 V, three-phase |
| Control | Preset angle stops, limit switch | Automatic + manual from foot paddle, heavy-duty panel | Adjustable angle settings, limit switch |
| Weight | 350 kg | 380 kg | 420 kg |
| Overall size | 850 × 790 × 900 mm | 850 × 790 × 900 mm | 900 × 800 × 800 mm |
| Matching bar cutter | GQ45 | GQ45 | GQ50 |
| Listed price | ₹88,500 | ₹1,18,000 | ₹1,18,000 |
| Best suited to | RCC buildings, mixed bending on site | Fabrication yards, long runs of repeat shapes | Bridges, flyovers, metro piers, heavy foundations |
Step 1: Find the largest bar in your bar bending schedule
A bar bending machine is rated by the largest deformed bar it can bend, and that rating is a hard limit, not a guideline. A machine rated to 32 mm cannot bend a 36 mm bar even once. So the question is not what bar you bend most often; it is what the single largest bar mark on the job is.
Go through the bar bending schedule, or the structural drawings if the BBS is not ready, and note the biggest diameter that has to be bent rather than used straight. On most residential and commercial buildings, slab and beam steel sits in the 8–25 mm range and column bars rarely go above 32 mm. Bar of 36 mm and 40 mm typically shows up in bridge and flyover decks, metro and viaduct piers, transfer girders, and heavy raft and pile-cap foundations.
- ✔ Largest bar 32 mm or below: GW42 or JBB42A. Go to Step 2.
- ✔ Any bar at 36 mm or 40 mm: GW50. Go to Step 3.
The reverse also holds: if your work never goes above 32 mm, there is no reason to buy the GW50. It is heavier, draws more power and costs more than the GW42, and that extra capacity sits unused.
Step 2: Up to 32 mm, choose GW42 or JBB42A by how you will run it
Mechanically, the GW42 and the JBB42A are the same machine. Both bend 6–32 mm deformed bar, both run the same 3 kW motor through the same gearbox, and both are built on the same outer body, which is why their photographs look alike. The difference is entirely in the control panel and how the operator drives the bend.
The GW42: the common choice on RCC sites
The GW42 is Jamshedji’s highest-selling bender and the machine most contractors put on a building site. Preset angle stops and a large limit switch give repeatable bends across a cutting list of stirrups, cranks, hooks and L-bends. Where a site bends a varied mix of shapes through the day, it does everything that is needed.
The JBB42A: when the same shape repeats hundreds of times
The JBB42A adds automatic and manual bending from the foot paddle. In automatic mode the machine completes the bend to the preset angle and returns on its own, so an operator working through a long list of identical bars keeps a steady rhythm without resetting between pieces. Switching to manual on the same paddle gives direct control for one-off bends and corrections. Its heavy-duty control panel is built for the dust, vibration and knocks of a busy rebar yard, which is what wears out control gear long before the bending mechanism.
Choose the JBB42A for a fabrication yard, a precast or ready-to-fix rebar unit, or a large project bending long runs of the same bar marks. Choose the GW42 for general site work with a varied cutting list.
Step 3: For 36 mm and 40 mm bar, the GW50
Bending force rises steeply with bar diameter, so a 40 mm bar needs a machine sized for it rather than a 32 mm machine pushed harder. The GW50 steps up to a 5 kW (6.5 HP) motor and a gear train sized for repeated large-diameter bending, and bends the full 6–40 mm range. It weighs 420 kg against 350 kg for the GW42.
Because it covers the whole range, one GW50 can handle both the 40 mm main bars and the smaller links on a heavy infrastructure job. That makes it the usual choice for bridge and flyover contractors, metro and viaduct work, port and power-plant foundations, and high-capacity fabrication yards supplying them.
Check the power supply before you order
All three machines run on 415 V three-phase supply. The GW42 and JBB42A draw 3 kW and the GW50 draws 5 kW, so confirm the site panel or DG set can carry the starting load, especially if other machines share the same supply.
If there is no three-phase supply, or bending has to happen floor by floor inside a building, a bench bender is the wrong tool. The portable bar bending machine weighs 30 kg, runs on single-phase power and still bends up to 32 mm, which is why it is used on redevelopment and increased-FSI projects where the bender is carried to the steel.
Quick decision guide
| Your situation | Machine |
|---|---|
| Largest bar up to 32 mm, varied bending on a building site | GW42 |
| Largest bar up to 32 mm, long runs of identical shapes in a yard | JBB42A |
| Any 36 mm or 40 mm bar in the schedule | GW50 |
| Up to 32 mm, no three-phase supply or floor-by-floor work | Portable bar bending machine |
| High-volume stirrups from 4–10 mm coil | CNC automatic stirrup bender |
| Spirals for piles and circular columns, 6–25 mm | Rebar spiral bending machine |
Pair the bender with a matching cutter
A bending machine is half of a cut-and-bend station. Match the cutter to the same bar range: the GQ45 bar cutting machine pairs with the GW42 or JBB42A, and the GQ50 bar cutting machine (up to 40 mm) pairs with the GW50. Wear parts such as the centre pin, which fits all three benders, are stocked at the Bhosari works.
Buying, GST and delivery
- ✔ Supplied with a GST invoice: 18% GST, CGST + SGST within Maharashtra, IGST interstate
- ✔ Sold outright; Jamshedji Constro Equip does not rent or hire equipment
- ✔ Dispatched F.O.R. Pune across India, with export to Bangladesh, UAE, Kenya, Tanzania, Sri Lanka and Nepal
- ✔ No fixed foundation needed; each machine is moved with a chain pulley block, mini crane or hydraulic pallet truck
- ✔ Manufacturer founded in 1983, ISO 9001:2015 and MSME/Udyam registered, with 5,000+ clients. Pune buyers can inspect the machines at our MIDC Bhosari factory before buying
Frequently asked questions
Which bar bending machine do I need for 32 mm bar?
The GW42 or the JBB42A. Both bend 6–32 mm TMT bar on a 3 kW motor. Choose the GW42 for general site work and the JBB42A if you want automatic paddle-controlled bending for long runs of repeat shapes.
Can the GW42 bend 36 mm or 40 mm bar?
No. The GW42 and JBB42A are rated to 32 mm. For 36 mm and 40 mm bar, use the GW50, which bends 6–40 mm on a 5 kW motor.
What is the difference between the GW42 and the JBB42A?
The control. Both have the same 6–32 mm capacity, the same 3 kW motor and gearbox and the same outer body. The JBB42A adds automatic and manual bending from the foot paddle and a heavy-duty control panel, and weighs 380 kg against 350 kg for the GW42.
Should I buy the GW50 just to be safe?
Only if your work includes 36 mm or 40 mm bar. If your largest bar is 32 mm or below, the GW42 does the same job at a lower price, lower weight and lower power draw.
What power supply do these bar bending machines need?
All three need 415 V three-phase supply. The GW42 and JBB42A draw 3 kW and the GW50 draws 5 kW. Where only single-phase power is available, the portable bar bending machine bends up to 32 mm on single phase.
Which bar cutting machine goes with each bender?
The GQ45 bar cutting machine pairs with the GW42 and JBB42A, and the GQ50, which cuts up to 40 mm, pairs with the GW50.
What is the price of a bar bending machine in India?
The GW42 is listed at ₹88,500, and the JBB42A and GW50 at ₹1,18,000 each. Send your site location and largest bar diameter on WhatsApp for a GST-inclusive quotation with freight.
Not sure which bender fits your job?
Send us the largest bar diameter in your schedule and your site location, and we will confirm the right machine with a GST-inclusive quote.
💬 WhatsApp +91 8484061252 📞 Call +91 8484061252Bar bending machines near you
- Bar Bending Machine Pune
- Bar Bending Machine Mumbai
- Bar Bending Machine Hyderabad
- Bar Bending Machine Bangalore
- All TMT Bar Machines
- Construction Machinery India
Specifications and listed prices are taken from the current Jamshedji product pages. Typical bar sizes by structural element are a general guide; always check the bar bending schedule and structural drawings for your project.