Neometrix / Hydraulic Torque Wrench Systems / Hydraulic Torque Wrench System / NMX-HTW-48

NMX-HTW-48 · ENGINEERED-TO-ORDER CLASS — SELECT · FIT · SET · TIGHTEN · CHECK · RECORD

Hydraulic Torque Wrench System. Torque is not tension.

Name: Hydraulic Torque Wrench System
Brand: Neometrix
SKU: NMX-HTW-48

A bolt holds a joint shut by being stretched. The nut is turned with a wrench, but the wrench only knows how hard it was turned, not how far the bolt stretched.

So the system has two jobs. It makes the turning repeatable, with one pressure for one torque, and it brings a joint up evenly, in stepped passes, so that no bolt is left carrying less than its share.

Discuss a hydraulic torque wrench Capability note (PDF)

Fig · 01 — A low-profile hydraulic torque wrench with its socket, reaction arm and twin hoses with quick couplings — illustrative render.

The pressure

set from the chartone pressure per torque

The reaction

a solid pointthe arm takes the load

The method

stepped passesin a cross pattern

The record

pressure and passesone record per joint

Status

engineered to orderno system yet delivered

ISO 9001ISO 14001ASME PCC-1 joint assembly referenceISO 898-1 fastener reference

Overview

Why a torque wrench is judged by the tension it never sees.

Because the joint needs the bolt stretched, and the wrench cannot measure that. It can only make the turning the same every time.

Fig · 02 — The system in one picture: a pump set from the chart, a piston that drives the ratchet, and a nut that turns while the arm reacts.

Pressure in, torque out. The bolt wants tension.

What the system is for

It tightens large bolts and studs to a commanded torque, using oil pressure from a pump to drive a wrench head. It is used where the nut is too big, or the torque too high, for a hand wrench.

Why pressure becomes torque

Oil pressure pushes a piston, the piston drives a ratchet, and the ratchet turns the nut. For one wrench, one pressure gives one torque, which is why the pump is set from a chart made for that wrench.

Why the arm needs a solid point

The wrench pushes on the nut, so something must push back. The reaction arm rests on a solid point, often the next nut, and it moves towards that point as the wrench works, so hands stay clear.

Why torque is not tension

Most of the effort at the nut is spent on friction in the threads and under the nut. Only a small share becomes stretch in the bolt, and friction varies from bolt to bolt, so the same torque gives different tension.

Why a joint is tightened in steps

A flange has many bolts, and tightening one relaxes its neighbours. So the bolts are brought up in several passes, in a cross pattern, until the last pass changes nothing.

Why calibration belongs to the system

A pressure chart is only as good as the wrench it was made for, and a wrench wears. The system carries the wrench's last calibration, so the torque it claims can be trusted.

The method

Select, fit, set, tighten, check, and record.

Six steps in a fixed order. The two shaded steps are the ones a rushed job skips.

FIG · 02HYDRAULIC TORQUE WRENCH SYSTEM · SELECT / FIT / SET / TIGHTEN / CHECK / RECORD — TORQUE IS NOT TENSION

The step people underrate is the target. A torque taken from habit and not from the joint can crush a gasket or leave a joint leaking, whatever the wrench says.

Fig · 03 — One joint, three outcomes: one fast pass, stepped passes, and the wrong chart — a drawing of the idea, with no values.

1 · Select

The target torque is taken from the joint, the bolt and the gasket, not from habit or from the biggest figure on the chart.

2 · Fit

The wrench, the socket and the reaction arm are set up, with the arm on a solid point and clear of hands.

3 · Set

The pump is set to the pressure the chart gives for this wrench and this torque.

4 · Tighten

The bolts are brought up in several passes, in a cross pattern, until a pass changes nothing.

5 · Check

A final pass at the full torque is made round the joint, and each nut is marked to show it was done.

6 · Record

Pressure, passes and the wrench's last calibration are kept, one record for each joint.

Work content

What the system contains, element by element.

Read it as a checklist: a system missing a row will buy that row back later, usually as a joint that leaks.

A single compact portable electric hydraulic pump unit on a workshop floor: a plain grey tube frame with a carry handle, a dark grey electric motor on a small grey reservoir, two black hoses with steel quick couplings coiled beside it, and a black cable to a small hand pendant with two plain buttons, and no people

Fig · 04 — A compact electric hydraulic pump with its hoses and a hand pendant, the power pack of the system — illustrative render.

Element	What it does	What matters
Wrench head	turns the nut	low-profile or square drive, chosen from the nut size and the room round it
Reaction arm	takes the reaction	made to rest on a solid point at the customer's joint, with its stroke clear of hands
Sockets & cassettes	fit the nut	made to the customer's nut sizes, a close fit so that the nut is not rounded
Pump & power pack	sets the pressure	electric or air-driven to suit the site, with a regulator that holds the set pressure through the stroke
Hoses & couplings	carry the pressure	twin-line hoses with quick couplings that cannot be crossed or left half made
Pressure measurement	shows the set pressure	a gauge or transducer read against the chart, and traceable
Pressure-torque chart	links pressure to torque	made for this wrench and its hoses, from its own calibration
Calibration	proves the chart	the wrench checked on a torque transducer, with the date and the result kept
Case & accessories	protect the set	a case that holds every part, so that none is lost between jobs
Procedure	fixes the sequence	select, fit, set, tighten, check and record, the same for every joint
Testing & documentation	prove the set before use	each wrench run against a reference, and a record the customer can inspect

The element that decides whether a torque is real is not the pump. It is the chart. A chart made for another wrench, or for last year's wrench, gives a torque nobody measured.

Fig · 05 — One set, three jobs: flanges and pipework, heavy equipment, and tight spaces, with the job picking the head and the arm.

Full specification — expand

Set	A low-profile or square-drive hydraulic wrench head; reaction arms and sockets made to the customer's nuts; an electric or air-driven pump with a pressure regulator; twin-line hoses with quick couplings; pressure measurement; a pressure-to-torque chart made for the wrench; calibration of the wrench on a torque transducer; a case; a written procedure; and testing and documentation before handover
The One Idea	A wrench controls torque. A bolt needs tension. The gap between them is friction
Why Pressure Becomes Torque	Oil pressure pushes a piston, the piston drives a ratchet, and the ratchet turns the nut, so for one wrench one pressure gives one torque, which is why the pump is set from a chart made for that wrench
Why The Arm Needs A Solid Point	The wrench pushes on the nut, so something must push back: the reaction arm rests on a solid point and moves towards it as the wrench works, so hands stay clear
Why Torque Is Not Tension	Most of the effort at the nut is spent on friction in the threads and under the nut, only a small share becomes stretch in the bolt, and friction varies from bolt to bolt, so the same torque gives different tension
Why A Joint Is Tightened In Steps	A flange has many bolts and tightening one relaxes its neighbours, so the bolts are brought up in several passes, in a cross pattern, until the last pass changes nothing
Why Calibration Belongs To The System	A pressure chart is only as good as the wrench it was made for, and a wrench wears, so the system carries the wrench's last calibration and the torque it claims can be trusted
Standards	ASME PCC-1 is the public guideline for the assembly of pressure-boundary bolted flange joints, ISO 898-1 is the public reference for the mechanical properties of bolts, screws and studs, and ISO 4413 is the public reference for the safety of hydraulic fluid power systems. None of them sets the torque for a particular joint: that comes from the joint's designer, and this page prints none of it. Approval of the finished set rests with the customer and the authority they name; none is claimed here
Configurations	A wrench set with its sockets and arms, a set with a power pack that adds hoses and a pump, and a set with calibration that adds a pressure chart and a record
Scope Boundary	This is the system that tightens bolts with oil pressure and a wrench head. It is not the bench that calibrates hand torque wrenches (see torque wrench machine), not a hydraulic spreader (see hydraulic spreader machine), not a plant power skid (see hydraulic power pack and actuator system), and not a bolt tensioner, which pulls the bolt directly instead of turning the nut: that is a different tool and none is claimed here
Status	Neometrix has quoted against successive hydraulic torque wrench and power pack requirements, and no delivered hydraulic torque wrench system is claimed.

Configurations

One method, three ways to supply the system.

The method, the record and the pass rule are shared. What changes is how much of the set is supplied.

Wrench set

Wrench, sockets and arms

A hydraulic wrench with its sockets and reaction arms, made to the customer's nut sizes and supplied in a case.

Set with power pack

Wrench, hoses and pump

The wrench set with twin hoses and a pump, electric or air-driven, ready to plug in and use.

Set with calibration

With its chart and record

The set supplied with a pressure chart made from its own calibration, and a record the customer can keep.

Fig · 06 — Three ways to supply the system, one method: a wrench set, a set with a power pack, or a set with calibration.

And the part that is not equipment at all, yet decides all three: the pass plan. It fixes the target, the number of passes and the order of the bolts, and it is written from the joint, not from the wrench.

Where it is used

Wherever a big joint has to be made up and kept tight.

The common thread is a joint that leaks or fails if one bolt carries less than its share.

Flanges and pipework

Where flanged joints are made up in pipework, vessels and plant, and must stay leak-tight.

Plant and machinery

Where large studs hold turbines, pumps and presses, and are loosened and made up again at every overhaul.

Heavy structures

Where large bolted connections on structures and towers need a known torque on every bolt.

Workshops and tool rooms

Where one calibrated set serves many jobs, with its record kept for each.

FAQ

Common questions.

Longer answers, for readers who want the reasoning.

Q · 01 How does a hydraulic torque wrench work?

A pump sends oil to the wrench, where the pressure pushes a piston. The piston drives a ratchet round the nut through a small angle, then retracts, and the stroke repeats until the set pressure is reached and the nut stops turning. For one wrench, one pressure gives one torque, which is why the pump is set from a chart made for that wrench. The wrench head can be compact because the pump, not the wrench, holds the power.

Q · 02 Why does the wrench need a reaction arm?

Because a force that turns a nut also pushes back on the wrench. The reaction arm rests on a solid point, often the next nut or the edge of a flange, and carries that push. It moves towards its point as the wrench works, so the point must be sound and hands must be kept clear. A set-up without a sound reaction point is the main way a hydraulic wrench becomes dangerous.

Q · 03 Why is a joint tightened in steps and in a pattern?

Because a joint has many bolts, and tightening one relaxes the ones beside it. If each bolt is taken to full torque in one go, the first bolts end up looser than the last and the gasket is crushed unevenly. Bringing every bolt up a little at a time, in a cross pattern, until a pass changes nothing, gives an even joint. ASME PCC-1 is the public guideline for the method.

Q · 04 Is this the same as the torque wrench machine, hydraulic spreader or power pack pages?

No, and the differences are worth stating precisely. The torque wrench machine page is a bench that calibrates hand torque wrenches, so it checks a tool. The hydraulic spreader machine page is a hydraulic tool that opens a gap rather than tightening a bolt. The hydraulic power pack and actuator system page is a plant-scale power skid for actuators, where the pump on this page is a small unit that drives one hand tool. This page does not replace any of them, and it does not claim what they claim a second time.

Q · 05 What can the system not do?

It controls torque, not tension: two bolts at the same torque can carry different tension, because friction differs. Where the tension itself must be known, a bolt tensioner that pulls the bolt directly is the better tool, and this page does not claim one. It cannot make a worn wrench accurate, which is why the calibration is kept with it. No torque, pressure or bolt figure is printed here, and no laboratory accreditation is claimed: this page claims none. Approval of a joint rests with the customer and the authority they name; none is claimed here.

Q · 06 Has Neometrix built one of these?

We would rather answer this plainly than let a page imply otherwise. Neometrix has quoted against successive hydraulic torque wrench and power pack requirements, and no delivered hydraulic torque wrench system is claimed. What stands behind the offer is adjacent: Neometrix engineers hydraulic power packs (see the hydraulic power pack and actuator system page) and bench systems that calibrate torque wrenches (see the torque wrench machine page). The wrench heads, sockets and quick couplings are specialist items, bought in, not invented. What Neometrix engineers is the system around them: the pump and its pressure control, the hoses, the reaction arms and sockets to the customer's nuts, the pressure chart, the calibration, the procedure and the records. So the honest position is that the system is engineered to order, the neighbouring disciplines are in the building, and the first set of this exact kind will be built around the customer's own joints rather than lifted off a shelf.

Q · 07 Which standards apply, and who sets the torque?

ASME PCC-1 is the public guideline for the assembly of pressure-boundary bolted flange joints, ISO 898-1 is the public reference for the mechanical properties of bolts, screws and studs, and ISO 4413 is the public reference for the safety of hydraulic fluid power systems. None of them sets the torque for a particular joint: that comes from the joint's designer and the decisions that rest on it, and this page prints none of it. Acceptance of the finished set, including its proving runs before handover, rests with the customer and whatever authority they name.

Q · 08 What do you need from us to quote?

Six things, and most of them describe your joints rather than the set. First, the bolts: their sizes, how many, and the nut shape. Second, the torque: the target for each joint and who sets it. Third, the access: the room round the nut and the points the arm can rest on. Fourth, the power: electric or air, and the site's rules for it. Fifth, the records: the chart, the calibration and the record you want kept. Sixth, the users: who will use the set and how often it is calibrated. From that we come back with a set list, a written method you can check, and a budgetary price.

The neighbouring hydraulic tool pages, and how they differ from this one.

Three neighbours: a bench for hand wrenches, a tool that opens, and a plant-scale power skid.

↗ The bench for hand wrenches

Torque Wrench Machine

A bench that calibrates hand torque wrenches - it checks a tool, it does not tighten a joint.

↗ A tool that opens

Hydraulic Spreader Machine

A hydraulic tool that opens a gap - the opposite job to tightening a bolt.

↗ A plant-scale power skid

Hydraulic Power Pack and Actuator System

A large power skid for actuators - the pump here is a small unit that drives one hand tool.

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Get a quotation

Tell us the bolts, the torque,
and the access.

The projects desk replies within two working days with a set list, a written method you can check, and a budgetary quotation. Write to [email protected] or use the form.

Enquire — hydraulic torque wrench Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED-TO-ORDER CLASS — HYDRAULIC TORQUE WRENCH SYSTEM SELECT · FIT · SET · TIGHTEN · CHECK · RECORD — TORQUE IS NOT TENSION ENGINEERED IN NOIDA · INDIA