The AirTAC Airtac SCJ40 Standard Cylinder SCJ40X125-20TC is a genuine double-acting SINGLE-ROD air cylinder with a rear-cap ADJUSTING SCREW: the stroke end is field-adjustable within a 20 mm range without swapping the cylinder. Ø40mm bore, 125mm nominal stroke, PT1/4 ports and adjustable end cushioning.
The SCJ40X125-20TC is a 40 mm bore, double-acting, single-rod pneumatic cylinder with a field-adjustable stroke end, giving you a 20 mm fine-tuning range on the 125 mm nominal stroke. Its rear-cap adjusting screw lets operators dial in the exact end position during commissioning or changeovers without swapping the cylinder or adding external hard stops. At 0.5 MPa, it delivers 628 N push and 528 N pull, and it uses a 16 mm diameter piston rod with an M12x1.25 male thread.
This TC-configured unit includes a centre trunnion pivot (F-SC40TC) and the matching TCM1 bracket, allowing the cylinder to swing as it strokes—ideal for pivoting linkages and articulated machine sections. The port is PT1/4, the air cushion is 21 mm, and the body length A(SCJ) is 185 mm. The operating pressure ranges from 0.15 to 1.0 MPa, with a proof pressure of 1.5 MPa.
| Model | Airtac SCJ40 Standard Cylinder SCJ40X125-20TC |
|---|---|
| Series | SCJ adjustable-stroke tie-rod cylinder |
| Bore size | Ø40 mm |
| Nominal stroke | 125 mm |
| Stroke adjustment | Up to 20 mm (rear adjusting screw) |
| Acting type | Double acting (single rod) |
| Port size | PT1/4 |
| Rod thread | M12×1.25 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Adjustable, 21 mm |
| Max stroke | Up to 1200 mm |
Specifications follow the official AirTAC SCJ (adjustable-stroke) datasheet. The rear adjusting screw sets the stroke end position; force is the same as the equivalent single-rod SC bore. Confirm against the product label before installation. Thread options: PT (standard) / G.
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | — |
| Max (@1.0 MPa) | 128 kgf | |
SCJ is single-rod, so force matches the equivalent SC bore: push uses the full bore area, pull subtracts the rod area. Actual usable force is lower than theoretical due to friction and back-pressure; size with a safety margin.
| SCJ | Adjustable-stroke tie-rod cylinder series. |
|---|---|
| 40 | Bore size in mm. |
| ×125 | Nominal (maximum) stroke length in mm. |
| -20 | Adjustable-stroke range in mm (options 10/20/30/40/50/75/100). |
| -S | Optional built-in magnet for sensor position sensing. |
Related types: SC (single rod, fixed stroke), SCD (double rod), SCT (multi-position). SCJ mounting: Basic, FA, LB, TC, TCM1. Seals: TPU standard / H = Viton / N = NBR. Thread: blank = PT, G = G thread.
During machine setup, the 20 mm adjustment screw allows technicians to precisely set the stroke end position to match tooling or product dimensions without re-plumbing or replacing the cylinder.
On packaging or assembly lines running multiple product sizes, operators can quickly adjust the cylinder stroke to accommodate different box heights or part positions, reducing downtime between batches.
In clamping or pressing fixtures, the adjustable stroke can be used to take up mechanical wear on pads or tooling over time, maintaining consistent contact force without modifying the machine program.
Choose this 40 mm bore when the 628 N push force at 0.5 MPa fits your load; if you need more force, step up to the 50 mm bore which provides 982 N push. The centre trunnion mount is correct for applications where the cylinder body must pivot during the stroke—if your load travels in a straight, rigid line, a basic or foot-mounted (LB) SCJ would be a simpler, more cost-effective choice. For a direct replacement, match the 40 mm bore, 125 mm nominal stroke, 20 mm adjust range, PT1/4 port, and TC mounting.
If your application demands a fixed, non-adjustable stroke, the standard SC series is a lighter, lower-cost alternative. For strokes of 300 mm or longer, evaluate side-loading and rod bending; an external guide rail or a guided cylinder assembly should be used to protect the rod bearing and seals from premature wear.
Adjustable-stroke checklist
At the standard 0.5 MPa operating pressure, this 40 mm bore cylinder provides 628 N of pushing force and 528 N of pulling force. At the maximum operating pressure of 0.9 MPa, the push force increases to 1130 N. Because it is a single-rod cylinder, the push force is always greater than the pull force.
Pick the SCJ when you need to fine-tune the stroke end position on the machine, such as during commissioning, for format changeovers, or to compensate for tooling wear. The rear adjusting screw provides a mechanical, field-adjustable stop within the specified range. If your stroke length is permanently fixed and never needs adjustment, the standard SC series is a simpler and more economical option.
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