Re-Grip Marks on a Torque-Turn Curve: What They Mean

A re-grip mark is the small step you see on a make-up curve each time the torque head releases the pipe, resets and grips again. Torque falls back, then climbs on the same line when rotation restarts. A step is normal on a fixed-arc machine. A step that resumes on a lower line is not,…

A re-grip mark is the small step you see on a make-up curve each time the torque head releases the pipe, resets and grips again. Torque falls back, then climbs on the same line when rotation restarts. A step is normal on a fixed-arc machine. A step that resumes on a lower line is not, and that is the difference worth learning to spot.

How many steps you get is arithmetic, not luck. Divide the rotation the head must deliver under torque by the arc it can swing in one stroke. A head with a 90 degree swing needs four strokes per turn, so three re-grips for every turn of make-up. A continuously rotating head needs none. The rest of this page shows how to count them, and how to judge each one against the trace.

Why continuous rotation leaves no steps

A rotational, fully continuous unit turns the connection in one unbroken 360° motion, with no stopping to re-grip. On premium connections that need a smooth, monitored make-up to the shoulder, that continuous rotation is the difference between a clean torque-turn curve and a stair-stepped one full of re-grip marks. If you are running casing or premium tubing in volume — dozens of joints a shift — the time you save not re-clamping adds up fast, and the make-up record reads cleaner for QA. This is the setup most threading lines and busy service centers end up choosing.

When a stepped curve is still acceptable

A traditional unit swings a fixed arc, releases, resets, and grips again. For a shop that makes and breaks a handful of connections a day — tool servicing, the odd drill-pipe job, a mixed bag of sizes — that is perfectly adequate, and it costs less up front. You trade cycle speed for a simpler, cheaper machine. If your throughput is low and the unit is not running all day, you rarely feel the difference.

Choosing a drive once you know your turns to shoulder

Purchase price is the easy number. The ones that actually bite are spares, service response, and operator training — a cheaper unit that sits idle waiting on a part is not cheaper. As a Chinese manufacturer, our advantage here is straightforward: a Galip rotational unit lands well below a Western-built machine of the same class, so you can often afford the continuous head for close to what a traditional import would cost, and still get spares and support direct from the factory.

Quick answers

Is rotational always the better option?
No. If you run low volume across mixed sizes, a traditional unit is the sensible buy.

What should break a close decision?
Throughput. Count the connections per shift honestly — that number decides it more than any single spec-sheet line.

Can a shop start traditional and move up later?
Yes. Plenty of shops pilot with a traditional unit and step up to a rotational head once volume justifies it.

Related: for backing connections out under high torque, see our hydraulic breakout unit.

If your step count keeps landing in double figures on premium work, the torque-controlled machines we build include continuous heads that take it to zero.

The same counting exercise applies in reverse on release, which is one reason why break-out runs higher than make-up and needs more strokes on a fixed-arc head.

Re-grip marks are one feature among several, so it helps to know how to read a make-up curve end to end before judging any single step.

If a step resumes on a lower line, park the joint and run the checks for damaged threads before make-up rather than pushing on to target.

Swing angle is set by the drive layout, so how drive structures change the swing angle decides the step count before anyone touches a control.

How to count re-grips and judge each step

Count the rotation the head has to deliver from thread engagement to final torque, after the pipe has been spun in. Then work out the strokes: strokes = turns under torque x (360 / swing angle in degrees), rounded up. Re-grip steps on the curve = strokes minus one.

Numbers in the table are worked examples. Take your own turn count off a recorded curve rather than off a catalogue, because thread run-in varies with pitch, taper and how well the joint was spun in.

With the count in hand, judge each step against these thresholds:

1. A torque drop of up to about 10 per cent of the value held at that point is normal on release. It is hydraulic bleed-back and elastic recovery in the joint, not damage.
2. On restart the trace should climb back to within about 5 per cent of the pre-release value inside 0.05 turn, then carry on at the same slope.
3. A resumption line with a visibly shallower slope means the joint has lost stiffness. Stop and inspect the threads before going further.
4. A step where turn advances while torque stays flat is not a re-grip artefact at all. That is stripping or a cross-thread, and the joint is scrap until proven otherwise.
5. No re-grip after shoulder contact. Once the shoulder is loaded, the final rise is the part of the curve QA is judged on, and releasing there makes the recorded final torque unreliable. If the head cannot reach final torque in one stroke after shouldering, it is the wrong machine for that connection.

The practical use of the count is triage. Eleven clean steps on a casing curve is a fixed-arc machine doing its job. Eleven steps where three of them sit lower than the one before is a thread problem hiding inside an artefact, and no operator spots that without knowing how many steps to expect in the first place.