TORQUE WRENCH SETING AND USING.
The purpose of a torque device is to measure amount of rotational force (torque) we apply to bolt type fasteners. Torque is measured as the amount of force times (X) the length of the lever arm.12.lb. means12 lb. (force or torque) applied at the end of a 1 inch. Lever (same as1 lb. Applied at the end of a 12.lever). The Tork-it (torque wrench) is a release type device. The mechanism release at a preset torque. It complied to ANSI Type3, Class A, Style 1, Screwdriver Grip torque wrench standards. You cannot apply more than amount of torque you preset.
TORQUE WRENCH TYPES:
- Deflecting beam
- Rigid case, dial indicating
- Adjustable value, snap-action,
- Impulse feel tee handle,
- ratcheting, preset (fixed value)
- Adjustable value, snap-action,
- Impulse feel, screwdriver
- Direct reading,
- Torque screwdriver
Figure 1 Torque Model 100F.
Torque Model 100F-20 – 100 ft,lb Duty Micro-precision Torque wrench foe fine equipment. Ratcheting and reverse type.
Figure 2 Torque Model 100F Scale sleeve and adjust handle.
Torque Considerations.
Select proper size and capacity torque wrench so that the working range shall not be lower than 20 percent for impulse feel torque wrenches and 25percent for screwdriver type torque wrenches, nor greater than the rated capacity of the torque wrench. Example: A torque wrench of which the lowest torqueing value is 10 and the highest torqueing value is 200, is considered to have a capacity of 200. The lowest 20 percent of this capacity would be 40, (20 percent of 200). Normal use of this wrench must be limited to values of 40 through 200. Preset torque wrenches or torque screwdrivers that are not adjustable by the user may be used at torque settings lower than 20 or 25percent of rated capacity limits if they have been properly certified for that torque setting.
-Prior to the use of any torque device that has a breakaway feature (includes torque screwdrivers which may have multiple break points as the handle is rotated 360 degrees), the torque device to be used must be cycled through the breakaway torque as recommended in the manufacturer's brochure. If the manufacturer's brochure is not available, set the torque device at the maximum setting and cycle through the breakaway torque at least six times. This can be accomplished by (typical example) securing the square tang of the wrench in a smooth jawed vise. This breakaway exercise can be performed at the beginning of a work shift or any time subsequent, however, it is not required more than once each shift (normally eight hours) on The specific torque wrench or wrenches to be used. The purpose of the breakaway procedure permits special internal lubricant to recoat internal working parts, eliminating internal resistance to give the most accurate reading possible.
-Large torque wrenches (150ft-lbs and over), may be exercised at the torque value they will be used at rather than their maximum setting.
On an impulse feel type wrench, to set the torque handle to the selected value, unlock, and adjust to the desired setting on the scale, then relock. Install required wrenching attachment on the square drive of the handle. Note the direction of the permanently etched arrow(s) on the barrel shaft of the torque wrench. This is the calibrated direction(s) of the torque wrench. Apply the wrench assembly to the fastener to be torqued and push or pull with a smooth and steady motion. When the torque applied reaches the predetermined torque setting of the handle, the handle will automatically release or “break” producing from approximately five (5) to 10 degrees free travel. This release is distinct, is easily detected by mechanic, and indicates completed torqueing action on the fastener
NOTE
A fast or jerky motion will result in an improperly torqued fastener.
Caution
Never use your torque wrench as a hammer or pry.
Never use torque device as a breaker,
Always store torque wrench set below 25% of capacity.
Loosen all bolts before re-torqueing.
Clean fasteners and apply a film of lubricant (Anti seize compound).
Be sure threads and threaded bolt hole are clean.
Use the correct size bit.
Use alternate diagonal tightening sequence. (See diagram)
Tighten at least three stages 50%, 75% and finally 100%.Torque must be do calibration check every 2 years.
Do not torque hot equipment, Let it cool. Several bolts or nut install on the same place suckas,
Setting the torque.
1. Turn the collar to the unlock position.
2.Hold the scale sleeve by knurl and turn the screwdriver handle CW.to increase the torque.(turn hand grip CCW.to decrease the torque.) to obtain torque between values stamp on the scale sleeve, adjust the handle until the sum of value on the scale sleeve and value on the handle equals (align) the desired value.(see figure 3)
3. While holding the grip at the proper setting, lock it in position by turning the lock collar to the lock position.
Caution
Do not try to lock the torque between increments on the hand grip.
Do not turn the hand grip more than one revolution above or below the scale stamp on the sleeve.
Recommended Maximum Torques (Steel bolts in to aluminum)
Bolt size |
Torque |
Socket Size |
2.0 mm. |
5-7 in-lb |
1.5 mm. |
2-56 |
6-8 in-lb |
5/64 in. |
2.5 mm. |
8-10 in-lb |
2.0 mm. |
4-40 |
12-14 in-lb |
3/32 in. |
3.0 mm. |
13-15 in-lb |
2.5 mm. |
5-40 |
14-18 in-lb |
3/32 in. |
6-32 |
17-21 in-lb |
7/64 in. |
4.0 mm. |
20-24 in-lb |
3.0 mm. |
8-32 |
22-26 in-lb |
9/64 in. |
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Figure 4Torque Tighten Sequence.
Several bolts, nuts and screws install on the same place must be tighten by sequencing method.
Note
Use the higher values for head bolts with longer thread engagement and the lesser values for backplate, valve covet etc. These value consider all threads in good condition.
Proper care and maintenance.
1. The torque is precision instrument and should be handle and store with care.
2. When the wrench is not in use, keep it set at the lowest setting.
3, Other than periodic calibration checks and adjustment, no maintenance is require.