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MOSTMaynard Operation Sequence

Technique

Work Measurement System

By Yogesh Nakhate

Methods - Time Measurement

H. B. Maynard was one of three persons instrumental in the creation

of MTM.

Kjell Zandin, while working in the Swedish Division of H. B. Maynard in the late 1960’s,

detected striking similarities in the sequence of MTM defined

motions whenever an object was handled.

Under MOST, the primary work units are no longer basic motions

as in MTM, but collections of these basic motions dealing with

moving object.

MOST makes the assumption that to move an object, a standard

sequence of events occurs.

Under MOST, objects can be moved in only one of two ways:

• They are picked up and moved freely through space -- the GENERAL MOVE.

• They are moved and maintain contact with another surface -- the CONTROLLED MOVE.

The MOST Family

• Basic MOST -- General Operations

• Mini MOST -- Repetitive Operations

• Maxi MOST -- Non-repetitive Operations

• Clerical MOST -- Clerical Operations

Maxi MOST is used to analyze operations that are likely to be

performed less than 150 times per week.

Basic MOST is used for operations that are likely to be performed more than 150 times

but less than 1500 times per week.

Mini MOST is used to analyze operations likely to be repeated more than 1500 times per week.

The Decision Diagram provides a simple procedure for selecting the

most appropriate MOST Work Measurement System to use.

The MOST Decision Diagram is based on +/- 5% accuracy and a

95% confidence level.

System Selection Charts may be used in lieu of the Decision

Diagram for choosing the best MOST Work Measurement

System to use.

The MOST Standard Form provides the analyst with a

simple, consistent format for analyzing work using the method.

It should be possible to complete a MOST analysis by observing two complete cycles of work in

slow motion.

If the method is well established and the analyst knows the

operation and conditions, the Basic MOST calculations can be made from the office and used to

predict the times for a new procedure.

General Rules for Using MOST

• Each sequence model is fixed.

• No letter may be added or omitted for the General or Controlled Move Sequence.

• In general, no letter may be added or omitted for the Tool Use Sequence, with a few exceptions.

TMU

TMU = Time Measurement Unit

1 TMU = 0.0006 minutes

1 TMU = 0.036 seconds

How it works

• The purpose of the MOST system is to calculate the cycle time for an operation based on Pre-determined time study data.

Doing the math• A typical MOST work sequence code would look like this:• A10 B6 G3 A6 P3 A0

• Step 1 add up all the subscript numbers 10+6+3+6+3+0= 28

(the subscript is the MOST index value)• Step 2 Multiple the sum of the index by 10

– This answer gives the TMU equivalent 28 x 10 = 280 TMU

• Step 3 Convert to time 280 TMU * .036 seconds = 10.08 seconds

1 TMU

General Move

Sequence

Four subactivities constitute the General Move Sequence

• “A” Action Distance (mainly horizontal)

• “B” Body Motion (mainly vertical)

• “G” Gain Control

• “P” Placement

Roughly 50% of all manual work occurs as a General Move.

The percentage runs higher for assembly and material handling

and lower for machine shop operations.

The General Move follows a fixed sequence of steps:

• Reach, either directly or in conjunction with body motions or steps.

• Gain control of the object.

• Move the object, as in “reach”.

• Place the object in temporary or final position.

• Return to the workplace.

The General Move Sequence Model

A B G A B P A

Action Distance (A)

This parameter is used to analyze all spatial movement or actions of the

fingers, hands, and/or feet.

A0 < 2 Inches

This is any displacement of the fingers, hands, and/or feet a distance

of 2 inches or less.

A1 Within Reach

Actions that are confined to an area described by the arc of the

outstretched arm pivoted about the shoulder.

A3 One to Two Steps

The trunk of the body is shifted or displaced by walking, stepping to the

side, or turning the body around using 1 or 2 steps.

More Than 2 Steps

Used with Action Distance data table to cover longer movements.

Body Motion (B)

This parameter is used to analyze either vertical motions of the body or the actions necessary to overcome an

obstruction or impairment to body movement.

B3 -- Bend & Arise, 50% Occurrence

Bend & Arise is required only 50% of the time during a repetitive activity.

B3 -- Sit or Stand without Moving Chair

When the body is simply lowered into a chair from an erect position,

without hand/foot motions required to manipulate the chair.

B6 -- Bend & Arise

From an erect standing position, the trunk of the body is lowered by

bending from the waist and/or knees to allow the hands to reach below the

knees.

B10 -- Sit or Stand

A series of several hand, foot, and body motions to move a stool / chair into position followed by the body

sitting or standing.

B16 -- Stand and Bend

This is a case where a sitting person must stand up and walk to a location to gain control of an object placed below knee level, where a Bend &

Arise is required.

B16 -- Bend & Sit

This applies when gaining control of an object requires a Bend & Arise

followed by a Sit prior to placing the object.

B16 -- Climb On or Off

This parameter variant covers climbing on or off a work platform on

any raised surface (~3 ft) using a series of hand and body motions to

lift or lower the body.

B16 -- Passing Through Door

Passing through a door consists of reaching for and turning the handle, opening the door, walking through the door, and subsequently closing

the door.

Gain Control (G)

This parameter is used to analyze all manual motions employed to obtain

complete manual control of an object(s) and to subsequently

relinquish that control.

G1 -- Light Object

Gain control of an object by grasping it as long as no difficulty is

encountered.

G1 -- Light Objects Simo

One hand gains control of a light object while the other hand obtains

another light object.

G3 -- Light Object(s) Non-Simo

While one hand is grasping an object, the other hand must wait before it can

grasp the other object.

G3 -- Heavy or Bulky

In grasping a heavy or bulky object there is a delay between when the

object is grasped and when it begins to move due to weight, bulk, etc.

G3 -- Blind or Obstructed

Access to the object is restricted because an obstacle prevents the

operator from seeing the object or creates an obstruction to the

hand/fingers in attempting to gain control.

G3 -- Disengage

An application of muscular force to free an object from its surroundings

typified by a need to overcome resistance followed by sudden

movement and recoil of the object.

G3 -- Interlocked

Interlocked means the object is intermingled or tangled with other objects and must be separated or

worked free before reaching control.

G3 -- Collect

Gain control of several objects jumbled together in a pile or spread

out on a surface.

Placement (P)

This parameter is used to analyze actions at the final stage of an

object’s displacement to align, orient, and/or engage the object with other object(s) before control of the object

is relinquished.

P0 -- Pickup Objects

This is “placement” in which no placement occurs. The object is

picked up and held.

P0 -- Toss Object(s)

Another “placement” where placement does not occur. The object

is released during the “action distance” (A) parameter without

placing motions or pause to point the object toward the target.

P1 -- Lay Aside

The object is placed in an appropriate locations with no apparent aligning or

adjusting motions.

P1 -- Loose Fit

The object is placed in a more specific location than described by the Lay Aside parameter, but with

tolerances so loose that only a modest amount of control is needed for

placement.

P3 -- Adjustments

Adjustments are defined as the corrective actions occurring at the point of placement, and recognized by obvious efforts, hesitations, or correcting motions to align, orient,

and/or engage the object.

P3 -- Light Pressure

Because of close tolerances or the nature of the placement, the

application of muscular force is needed to seat the object.

P3 -- Double

With “double”, two distinct phases occur during the total placing

activity.

P3 -- Loose Fit Blind

In this case the operator must feel around for the placement location

before a loose placement can occur.

P6 -- Care or Precision

Extreme care is needed to place an object within a closely defined

relationship with another object, and characterized by the obvious slow motion of the placement due to the

high degree of concentration required.

P6 -- Heavy Pressure

As a result of very tight tolerances, a high degree of muscular force is

needed to engage the object.

P6 -- Blind or Obstructed

Accessibility to the point of placement is restricted because an

obstacle prevents the operator from seeing the point of placement, or

creates an obstruction to the hand/fingers when attempting to

place the object.

P6 -- Intermediate Moves

Several intermediate moves of the object are required prior to placing.

General Move Example

From a stack located 10 feet away, a heavy object must be picked up and moved 5 feet and placed on top of a workbench with some adjustments.


An assembly worker gets a handful of washers (6) from a bin located within

reach and puts one on each of six bolts located within reach, which are

four inches apart.


A worker gains control of two fittings that are within reach and located

more than two inches apart, one at a time, and places them on separate

trays that are within reach and located less than 2 inches apart.

Controlled Move

Sequence

Three new subactivities are found in the Controlled Move Sequence

“M” Move Controlled

“X” Process Times

“I” Align

The Controlled Move Sequence describes the manual

displacement of an object over a “controlled” path.

The Controlled Move follows a fixed sequence of steps:

Reach, either directly or in conjunction with body motions or steps.

Gain control of the object.

Move the object over a controlled path.

Allow time for the process to occur.

Align the object after the move/process.

Return to the workplace.

A Controlled Move is performed under the following conditions:

• The object or device is restrained by its attachment to another object

• It’s controlled during the move by the contact it makes with the surface of another object.

• It must be moved on a controlled path to accomplish the activity.

Move Controlled (M)

This parameter is used to analyze all manually guided movements or

actions of an object over a controlled path.

M1 -- One Stage < 12”

Object displacement is achieved by a movement of the fingers/hands/feet

not exceeding 12 inches.

M1 -- Button/Switch/Knob

The device is actuated by a short pressing, moving, or rotating action

of the fingers/hands/wrist/feet.

M3 -- One Stage > 12”

Object displacement is achieved by a movement of the hands, arms, or feet,

plus body motion, exceeding 12 inches.

M3 -- Resistance, Seat/Unseat

Conditions surrounding the object or device require that resistance be

overcome prior to, during, or after the Controlled Move.

M3 -- High Control

This parameter reflects the need to align an object using a high degree of

visual concentration.

M3 -- Two Stages < 12”

An object is displaced in two directions or increments a distance not exceeding 12 inches per stage

without relinquishing control.

M6 -- Two Stages > 12” -- OR-- With One - Two Steps

An object is displaced in two directions or increments a distance

exceeding 12 inches per stage without relinquishing control.

M10 -- Three to Four Stages --- OR --- 3 - 5 Steps

An object is displaced three or four directions or increments without

relinquishing control or pushed/pulled on a conveyor belt.

M16 -- Move Controlled with 6 - 9 Steps

Push or pull an object(s) using 6 - 9 steps.

“Cranking” action is performed by moving the fingers, hand,

wrist, and/or forearm in a circular path more than half a revolution.

Less than this is considered a Push/Pull/Pivot.

Push - Pull Cranking

If cranking results in a back - and - forth movement of the elbow instead

of pivoting at the wrist and / or elbow, it is considered push - pull

cranking.

Pivotal cranking is more efficient than push - pull cranking, and

should be used whenever possible.

Process Time

Process time is that portion of work controlled by electronic or

mechanical devices / machines, not by manual actions.

As a rule of thumb, the process time expressed as an index

number should not exceed 20% of the cycle time.

Alignment refers to manual actions following the Move

Controlled or at the conclusion of process time to achieve an

alignment or specific orientation of objects.

Within the area of normal vision (a 4” diameter circle), the

alignment of an object to two points can be performed without

any additional “eye times”.

I1 -- To One Point

Following a controlled move, an object is aligned to one point.

I3 -- To Two Points < 4” Apart

The object is aligned to points not more than 4 inches apart following a

Controlled Move.

I6 -- To Two Points > 4” Apart

The object is aligned to points more than 4 inches apart following a

Controlled Move.

I16 -- Precision

The object is aligned to several points with extreme care or precision following a Controlled Move.

I3 -- To Workpiece

A Machining Operations parameter where the machine tool is aligned to the workpiece prior to making a cut.

I6 -- To Scale Mark

Another Machining Operations parameter, the machine tool is aligned to a scale mark prior to

making a cut.

I10 -- To Indicator Dial

The third Machining Operations parameter, the machine tool is

aligned to the correct indicator dial setting prior to making a cut.

Alignment of Nontypical Objects

Nontypical objects are those that are especially large, flimsy, sharp, or

require special handling.

Alignment of a nontypical object normally takes place as a series

of short correcting motions (< 2”) following the Controlled Move,

usually with the assistance of stops, guides, or marks.

Controlled Move Example

From a position in front of a lathe, the operator takes two steps to the side, turns the handwheel two rotations, and sets the cutting tool by aligning the handwheel dial to a scale mark.


A milling machine operator walks four steps to the quick-feeding cross

lever and engages the feed. The machine time following the 4” lever

action is 2.5 seconds.


A material handler takes hold of a heavy carton with both hands and

pushes it 18” across conveyor rollers.


Using the foot pedal to activate the machine, a sewing machine operator makes a stitch requiring 3.5 seconds

process time. The operator must reach the pedal with the foot.

The Tool Use Sequence is a combination of the General Move and Controlled Move activities.

Tools not listed in the tables that are similar to a tool in the table

can use their time values for analysis.

Tool Use Phases

• Get Tool (Object)

• Put Tool (Object) in Place

• Use Tool

• Put Tool (Object) Aside

• Return

The Tool Use Sequence model makes use of the “A”, “B”, “G”, and “P” parameters, which are all familiar to us, plus the new Tool

Use parameters.

The Tool Use Sequence Model

A B G A B P * A B P A

* consists of the “tool use” parameters F, L, C, S, M, R, & T.

Tool Use Sequence Parameters

• F -- Fasten

• L -- Loosen

• C -- Cut

• S -- Surface Treat

• M -- Measure

• R -- Record

• T -- Think

Fasten / Loosen

Manually or mechanically assembling or disassembling one object to or from another using the fingers, a

hand, or hand tools.

Index values for “F” and “L” are determined by the body member

performing the action.

Finger Spins are the movement of the fingers and thumb to run a threaded fastener down or out,

and include a light application of pressure for seating / unseating

the fastener.

Wrist Actions

• Wrist Turn

• Wrist Stroke (with reposition)

• Wrist Crank

• Tap

Wrist Turn

During a wrist turn, the tool is not removed from the fastener during use and not repositioned on the fastener

after an action.

Wrist Stroke (with reposition)

In this tool use, after each stroke with the tool and before making each

subsequent stroke, the tool must be removed from the fastener and

repositioned.

Wrist Crank

Wrist crank applies to tools that are spun or rotated around a fastener

while remaining affixed to it.

Tap

This parameter covers the use of a hammer (or similar device) to exert

short tapping motions by pivoting the hand at the wrist.

Arm Actions

• Arm Turn

• Arm Stroke (with reposition)

• Arm Crank

• Strike

• T-Wrench (two hands)

Arm Turn(s)

Arm Turn(s), applying to ratchets, occur when the tool is held near the

end of the handle, resulting in a pulling action on the tool.

Arm Stroke (with reposition)

Following each stroke or pull with the tool, it must be removed and

repositioned again on the fastener before making a subsequent pull.

Arm Crank

The tool is used with a circular movement of the forearm as it is

pivoted at the elbow or the shoulder to push or crank the tool around the

fastener.

Strike

Strike is the use of a hammer with an up - and - down motion performed with the hand as it is pivoted

from the elbow.

T-Wrench (two hands)

A two - handed arm action, including the reach for each hand to the

opposite handle before making the next turn, and involving a 180 degree

turn of the T-wrench with each action.

Power Tools

The use of electric and pneumatic power wrenches to run a standard threaded fastener down or out a

length 1 1/2 times the bolt diameter.

The time values generated by the data card for power tool use must

be compared to the times generated by the tools used in the shop, and adjusted if necessary.

Torque Wrenches

• F6 -- Torque wrench handle length to 10”.

• F10 -- Handle length from 10 - 15”.

• F16 -- Handle length from 15 - 40”.

• In all cases, the value is for one arm action and includes the time either to align the dial or to await the click.

Tool Placement

As a general rule, the “P” parameter for the Fasten / Loosen tools will

carry the index values indicated in the Tool Placement table.

Tool Use Frequencies Example

An operator picks up a screwdriver within reach and tightens two screws with six wrist turns each and then sets

aside the screwdriver.

Multiple Tool Actions Example

A screw is fastened with a screwdriver. A total of 18 spins and

4 wrist turns are necessary.

Multiple Tool Actions Example

A nut is fastened with a ratchet wrench. Following 3 wrist cranks, 6

wrist turns are applied.

Tool Use Example -- F / L

Obtain a nut from a parts bin located within reach, place it on a bolt, and run it down with 7 finger actions.

Tool Use Example - F / L

Pick up a small screwdriver that lies within reach and fasten a screw with

6 finger actions, and set aside the tool.


Obtain a power wrench that lies within reach, run down four 3/8”

bolts located 6” apart, and set aside wrench.


From a position in front of an engine lathe, obtain a large T-wrench located 5 steps away and loosen one bolt on a chuck on the engine lathe with both hands using five arm actions. Set

aside the T-wrench from the machine, but within reach.

Cut

• Pliers

• Scissors

• Knife

Pliers

• C3 -- Soft: Using pliers with one hand and making one cut.

• C6 -- Medium: Using pliers with one hand and making two cuts.

• C10 -- Hard: Using the pliers with two hands and making two cuts.

Pliers

• C1 -- Grip:Using pliers to hold an item and subsequently release the pressure on the item.

• C6 -- Twist: Close pliers jaws on two wires and use two twisting actions to join the wires together.

• C6 -- Form Loop: Close pliers jaws on wire and using two actions, bend loop in end of wire.

• C16 -- Secure Cotter Pin: Use pliers to bend both legs on cotter pin to hold it in position.

Index values using scissors are selected according to the number

of cuts used.

Tool Use Example -- Cut

An operator picks up a knife from a workbench two steps away, makes

one cut across the top of a cardboard box, and sets aside the knife on the

workbench.


During a sewing operation, a tailor cuts the thread from the machine before setting aside the finished

garment. The scissors are held in the palm during the sewing operation.


Following a soldering operation, an electronic component assembler must cut off the excess small - gauge wire

from a terminal connection. The pliers are located within reach.


An electrician working on transmission lines takes a pair of

pliers from the tool belt and cuts off a piece of line. The line is heavy, such

that 2 hands are needed to cut through the wire.

Surface Treat

Surface Treat covers the activities aimed at cleaning material or particles from or applying a

substance, coating, or finish to the surface of an object.

Index values for cleaning tools are based primarily on the

amount of surface area (sq. ft.) cleaned.

Tool Use Example: Surface Treat

Before marking off a piece of sheet metal (4 ft sq) for a cutting operation,

the operator takes a rag from his or her back pocket and wipes an oily

film from the surface.


Following a sanding operation, an operator standing at a workbench picks

up a brush located within reach and brushes the dust and chips from the working are (6 ft sq), and then sets aside the brush on the workbench.


Before assembling three components to a casting, the operator obtains an air

hose (within reach) and blows the small metal filings left from the previous

machining operation out of 3 cavities. The distance between cavities is > 2”.

M10 -- Profile Gauge

Used to compare the profile of an object to that of the gauge.

M16 -- Fixed Scale

Covers the use of a linear (yardstick) or angular (protractor) measuring

device.

M16 -- Calipers < 12”

Covers the use of vernier calipers with a capacity to 12 inches.

M24 -- Feeler Gauge

Covers the use of a gauge to measure the gap between two points.

M32 -- Steel Tape < 6 Ft.

This parameter covers the use of a steel tape to measure, from a fixed

position, between two points.

Micrometers < 4”

• M32 -- Depth measurement

• M42 -- Outside diameter measurement

• M54 -- Inside diameter measurement

Tool Use Example -- Measure

Before welding two steel plates, a welder obtains a square and checks the angle between the plates to see

that it is correct. The square (a profile gauge) is located three steps

away on a workbench.

Tool Use Example -- Measure

Following a turning operation, a machinist checks the diameter of a small shaft with a micrometer. The

micrometer is located on and returned to the workbench 2 steps away.

Measure Supplemental Values

• M6 -- Snap gauge; OD to 2”

• M10 -- Snap gauge; OD to 4”

• M16 -- Plug gauge; go/no-go to 1”

• M24 -- Thread gauge; go/no-go int/ext to 1”

• M24 -- Vernier Depth Gauge; to 6”

• M42 -- Thread gauge; go/no-go int/ext 1-2”

Record

• Write: covers routine clerical activities. » Index value based on number of digits or words

• Mark: covers marking object» Each mark is considered a “digit”

Tool Use Example -- Record

After finishing an assigned job, the operator picks up a clipboard and

pencil (simo) from the workbench, fills out the completion date on the

job card, and signs his name. He then returns the board and pencil to the

workbench.


To order a part, a clerk takes a pencil from her shirt pocket and writes a six-

digit part number on the requisition form on her desk. She then clips the

pencil back in her pocket.


Part of a packing operation involves identifying the components in the

carton. This involves picking up a felt marker (within reach) and marking a

6-digit number on the container.

Think

Most of the time “think” occurs internal to the manual work, but there are times it must be considered as a

separate activity.

Think -- Inspect

The type of inspection work we’re looking at here is that where only

simple “yes / no” decisions are quickly made on the existence of a

particular defect in a part.

Inspect -- Read

• The column Digits or Single Words is to be used for reading technical data (part numbers, codes, quantities, etc.)

• The column Text of Words is used when analyzing situations in which the operator reads words arranged into sentences or paragraphs.

• Other, specialized, values exist for reading gauges, scales, date/time, & tables.

Tool Use Example -- Think

During a testing operation, an electronics technician picks up a

meter lead, places it on a terminal, and reads voltage off the meter scale.

The lead is then put aside.

Tool Use Example -- Think

Prior to starting a turning operation, an operator picks up a work order set and

reads a paragraph that describes the method to be followed. It contains an

average of 30 words. The operator then places the set aside on the workbench.

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