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Precision Instruments, Inc.

The Finest Torque Products

Incorporated since 1938

Toll-free:(866)T WRENCH
(866)897-3624

All American made from domestic steel

Click here for informational charts

Factors That Affect Torque
Hand Hold positions and Extensions

  Change to Wrench

Torque Output

D C M
Hand hold position moved toward the square drive. No Change

wpe11.jpg (807 bytes)

wpe11.jpg (807 bytes)

Hand hold position moved away from the square drive No Change

wpe12.jpg (803 bytes)

wpe12.jpg (803 bytes)

Extension added to the square drive end.

wpe11.jpg (807 bytes)

wpe11.jpg (807 bytes)

wpe11.jpg (807 bytes)

Extension added to the handle end.

No Change

wpe12.jpg (803 bytes)

wpe12.jpg (803 bytes)

Angle extension added to the square drive end. See Formula in below

HOW TO COMPUTE TORQUE WHEN USlNG ADAPTORS

If an adaptor or extension is attached to the square drive of a click-type torque wrench and this adds to its length, then the applied torque will be greater than the pre-set torque. A formula can be used to find what the preset-set torque should be in order to obtain the correct applied torque.

Here is the formula:

 Pre-set_torque_formula.jpg (7562 bytes)

RS = Torque setting of the torque wrench.

 wpe1E.jpg (3367 bytes)

 A = Distance from the center of the square drive of the torque wrench to the center of the handle grip pull point.
B = Length of the adaptor from the center of the square drive to the center of the nut or bolt. Use only the length which is parallel to the handle. See figure 1
T = Torque desired. This is the actual torque applied to the fastener. Here is a typical problem: What should the setting be when ‘‘A’’ is 12’’, ‘‘B’’ is 6’’ and ‘‘T’’ is 30 Ib. ft.

 wpe1F.jpg (4866 bytes)

Therefore 30 pound foot of Torque will be applied at the fastener when ‘‘RS’’ is 20 pound foot.

Note: If the torque wrench reads in pound foot, then ‘‘T’’ should also be in pound foot. ‘‘T’’ and ‘‘RS’’ should be in the same unit of measurement. ‘‘A’’ and ‘‘B’’ should also be the same unit of measurement.

TE_Adaptor_Views (11K)

 

CONVERSION OF VARIOUS UNITS OF TORQUE

Convert

Convert

From

To

Multiply

From

To

Multiply

lb.in.

oz.in.

16

oz.in.

lb.in.

.0625

lb.in.

lb.ft.

.08333

lb.ft.

lb.in.

12

lb.in.

kg.cm.

1.1519

kg.cm.

lb.in.

.8681

lb.in.

kg.m.

.011519

kg.m.

lb.in.

86.81

lb.in.

N•m

.133

N•m

lb.in.

8.85

lb.in.

dN•m

1.13

dN•m

lb.in.

.885

lb.ft.

kg.m.

.1382

kg.m.

lb.ft.

7.236

lb.ft.

N•m

1.356

N•m

lb.ft.

.7376

N•m

dN•m

10

dN•m

N•m

.10

N•m

kg.cm.

10.2

kg.cm.

N•m

.09807

N•m

kg.m.

.102

kg.m.

N•m

9.807

 

Question: What does the "M" in a D2F150HM stand for?

Answer: Memory model Retains the highest torque reading for easy reference. For Quality Control testing, a memory model displays the maximum reading obtained. This is excellent for verifying production torque applications.

Question: How do I use the "M" (Memory model) option properly?

Answer: To use the Memory model in the clockwise direction, rotate knurled knob counter clockwise on top of crystal until the memory pointer contacts main pointer. Next turn the dial bezel counter clockwise until the memory pointer is on zero. Place the torque wrench on the fastener and pull on the wrench handle until the desired torque is reached. When the pressure is released the main pointer will return to zero and the memory pointer will remain at the peak torque reached. For counter clockwise direction use, reverse above procedure. The memory model feature can be used to record peak torque when the dial may not be visible. Be careful not to overtorque the fastener or torque wrench.

Question: What does the "L" in a D2F150HL stand for?

Answer: Indicator Light Model Indicates when a preset torque level is achieved. Set the dial to the required torque, and the light will go on when the proper torque is reached. This is particularly useful when the dial is not visible.

Question: How do I use the "L" (Lighted) option properly?

Answer: To use the Indicator Light Model for clockwise applications, turn the dial until the gold pointer is set at the desired torque (the red pointer for counterclockwise applications). Place the torque wrench on the fastener and pull until the light comes on. Check the bulb and battery if the light fails to light when the pointer touches the gold contact pin.

Question: What is the difference between a "C4D600F" and the "CP4D600F"?

Answer: The CP4D600F is a preset model meaning that the wrench comes from factory preset to a specific torque. A user with a torque tester can also adjust the torque setting.

Question: Where should preset models be used?

Answer: Preset torque wrenches such as the CP click wrench series and the MSP fully releasing driver type wrench are best suited to applications where a specific torque is applied over and over. They provide the user with the ability to set the torque and be assured that the setting will not accidentally be changed during production.

Question: Is a "M" micrometer style wrench calibrated in the same way as other micrometer style wrenches?

Answer: NO! The "M" series requires special tools available to perform calibration. DO NOT DISASSEMBLE a "M" wrench as you would other micrometer style wrenches! The mechanism in the "M" does not rely on shims, spacers or blocks to perform calibration. Instead, all calibration is performed externally, quickly, and without the need to disassemble the wrench. This keeps the internal components free from outside contaminates, eliminates calibration kits, and makes "tweaking" the calibration very simple.

Question: How often do torque wrenches require calibration?

Answer: The more a wrench is used, the more it will require calibration. Every wrench regardless of use should be calibrated at least every six months to ensure perfect calibration. Production units may require calibration every month, week, or day! Users should be encouraged to maintain wrench calibration and, when establishing their calibration intervals, to request calibration certificates that indicate the readings after the calibration and as the wrench was received.

Question: Which click wrenches have to be turned down to the bottom of the scale for storage?

Answer: Every click wrench other than the "C" series must be returned to the bottom of the scale after use. Springs in micrometer style wrenches will "take a set" after time and this will affect the calibration of the wrench. The "C" series does not use a coil spring and therefore can be stored at any value.

Question: Which torque wrenches work in both directions?

Answer: ALL torque wrenches other than the "C" series work in both directions. The "C" series works only in the clockwise direction, except the C4D600F series’ ratchet can be flipped over to allow for counter-clockwise applications. The accuracy of the D and QT series is the same clockwise and counter-clockwise, but other wrenches may have different specifications based on direction.