Palace119 Power Tools

Snap Torque

I'm screwed help?

trying to break loose crankshaft pully bolt on 22r just broke a 1 inch 19mm socket (snap-on) with 1200 lbs of torque with air gun. what else can i try breaker bar broke 2 sockets broke neumatic socket broke . anyone with any ideas woth 10 points
does any one know the direction of the crankshaft bolt for the 22r
i have tried loosing it in both directions
$100 to any one who can get this bolt off

I generally use a lubricant like "Break Free" or a penetrating oil like, "Liquid Wrench" before I try to remove a potentially frozen nut or bolt. I allow the part to sit overnight after applying the oil and then the next day bang on it with a rubber mallet to loosen the rust. Works for me. Sometimes I get frustrated and freeze the nut/bolt with some liquid nitrogen, this causes the part to shrink a little allowing the two threads to separate. If you don't have liquid Nitro, you can use ice.

Snap on torque wrenches

Pro Torque

Best power/torque/speed gain for a BMW 325i?

Hi guys

I have a 1992 BMW E36 325i, carbon fibre panels so very light. Cars ecu has been chipped, and the limits are endless. Car has gained alot more power, no speed barrier or rev count. You'd be a GREAT help if you could tell me the pros and cons..

Supercharger Kit
Turbo Kit
NOS Kit
ecu chipped. k&n cold air intake. factory 3 series, 2.5L injected engine.
Thanks for your answer man, big help. Carbon fibre, yeah.. bit early huh? I just wanted the look more than anything.. only the hood & boot.
Has air breathers, and the cold air intake. Fluidyne radiator, NGK platinum plugs & leading, remus headers, fuel management system, 550hp fuel pump & an ark cat back exhaust. Factory suspension, apart from rear koni struts and shocks.
Oh.. its an automatic, lol. Have everything for a conversion though, might get some better pulleys and maybe machine the flywheel. Possibly get an exedy clutch kit.

you have an OK start. I am confused about going carbon fiber so early, but hey its your car

supercharger kit - big money, power added throughout all rpms
turbo kit - big money, larger gains but power is only added in generally after 3k rpm
NOS - relatively cheap, great for a couple thousand miles of use till your engines internals start to warp & fall apart.

before you start throwing money into a supercharger, you want to get a aftermarket intake manifold, throttle body spacer, headers, high flow cats, mufflers, platinum plugs, wires, lightweight rims, sport tires, upgrade your sway bars, buy strut tower bars, pillar bars, lightweight flywheel, lightweight pulleys, clutch

EDIT: i wish you posted this a month ago, I actually had a virgin crate engine for this car I picked up at an auction. Would have been awesome to pull apart and build with bullet proof internals
ah well, maybe next time

ProTorque Racing customers

High Torque

What's the Difference between Super Torque Motors, And High Speed Motors in Airsoft?

I'm just wondering what's the difference between the two?

Thanks.

Depends on your spring and gears. For a stronger spring you need torque up gears along with a super torque motor to run the gears and pull that strong spring back. Of course I'm only talking about the motor and gears; there are many other parts that will have to be upgraded. As for High speed motors, they can be used in conjunction with a lighter spring to make the most out of it and increase the rate of fire.

TV HIGH TORQUE Válvula termostática.

Wrench Automotive

Who makes the best torque wrenches for automotive use?

Snap-On is very expensive. Who makes the best torque wrench that has the best value. Also which size is good for all-around use. Can you just buy a 1/2" and use a 3/8" adapter. Or can I just buy a 3/8" size. I don't think I can afford to buy more than one right now so it's either a 1/2" or 3/8" but I don't know which one to buy. Any advice?

The cheap wrenches, like from Harbor Freight, are better than nothing. They're usually off by about 10% and they don't stay in adjustment very long. You don't have to spend Snap-on, Mac, or Matco kind of money though. Central tools makes very good precision tools and you can find them at discount tool sites like tooldiscounter.com.

Most 3/8" wrenches are good for low torque uses like small bolts and spark plugs. Using a large 1/2" drive wrench in those applications will work physically with an adapter, but the torque will be way off. Spark plugs in aluminum heads can be as little as 15 ft/lbs. The lowest a 1/2" wrench goes is 20 ft/lbs and even then they're not accurate at the low end of the scale. So it really depends on what kind of work you're doing.

If you're putting in head gaskets, spend the money for a really good 1/2" wrench.

Orange County Fire at Golden Wrench Automotive

Drive Wrench

Which is the better 3/8” torque wrench for me... range of 10-80Nm, or one with range of 27-108Nm?

I want a 3/8” torque wrench for doing stuff on my car....

Which do you think would be most versatile for most of my auto needs?

(I know little about auto mechanics but have been doing some of the easier jobs so far.... and maybe more in the future, excluding timing belt - so am looking for which torque wrench range might offer the best option for most of the easier jobs I might encounter)

The one with range of 10-80Nm:

http://www.toolsnstuff.co.uk/product_info.php?pName=38%22-SQUARE-DRIVE-10-80-NM-OR-885-708-IN-LB-RATCHET-TORQUE-WRENCH&products_id=8102&osCsid=f518ef2049aa6cadaa616f100bcbb98b

Or the one with range of 27-108Nm?

http://www.toolsnstuff.co.uk/product_info.php?pName=Torque-Wrench-38%94Sq-Drive&products_id=16454&osCsid=f518ef2049aa6cadaa616f100bcbb98b

I realize that neither is an uber precision style Teng, Snap-On ect... cause I just can't afford it tbh.

Thanks

Hi Retardboy. I suggest you go for a 1/2" drive instead. If you intend doing more ambitious stuff like cylinder heads, a 3/8" drive is really not up to the job. Check out www.machinemart.co.uk. They do a 1/2" drive with a range of 28-210Nm for around the £15 mark. It comes with adaptors for use with 3/8" & 1/4" sockets as a bonus. Cheers!

Used Ingersoll Rand #5RANC1 Screw Gun Impact Wrench 1/4" Drive on sale at www.toolsez.com 562-653-9474

Torque Angle

Dynamic Analysis of Stepper Motor Mechanism

A force of one pound will accelerate a mass of one slug at one foot per second squared. The same relationship holds between the force, mass, time and distance units of the other measurement systems. Most people prefer to measure angles in degrees, and the common engineering practice of specifying mass in pounds or force in kilograms will not yield correct results in the formulas given here! Care must be taken to convert such irregular units to one of the standard systems outlined above before applying the formulas given here!

 

Statics

For a motor that turns S radians per step, the plot of torque versus angular position for the rotor relative to some initial equilibrium position will generally approximate a sinusoid. The actual shape of the curve depends on the pole geometry of both rotor and stator, and neither this curve nor the geometry information is given in the motor data sheets I've seen! For permanent magnet and hybrid motors, the actual curve usually looks sinusoidal, but looks can be misleading. For variable reluctance motors, the curve rarely even looks sinusoidal; trapezoidal and even assymetrical sawtooth curves are not uncommon.

 

For a three-winding variable reluctance or permanent magnet motors with S radians per step, the period of the torque versus position curve will be 3S; for a 5-phase permanent magnet motor, the period will be 5S. For a two-winding permanent magnet or hybrid motor, the most common type, the period will be 4S, as illustrated in Figure 2.1:

 

Figure 2.1

Again, for an ideal 2 winding permanent magnet motor, this can be mathematically expressed as:

T = -h sin( ((/2) / S)  )

Where:

T -- torque

h -- holding torque

S -- step angle, in radians

 = shaft angle, in radians

But remember, subtle departures from the ideal sinusoid described here are very common.

The single-winding holding torque of a stepping motor is the peak value of the torque versus position curve when the maximum allowed current is flowing through one motor winding. If you attempt to apply a torque greater than this to the motor rotor while maintaining power to one winding, it will rotate freely.

 

It is sometimes useful to distinguish between the electrical shaft angle and the mechanical shaft angle. In the mechanical frame of reference, 2 radians is defined as one full revolution. In the electrical frame of reference, a revolution is defined as one period of the torque versus shaft angle curve. Throughout this tutorial,  refers to the mechanical shaft angle, and ((/2)/S) gives the electrical angle for a motor with 4 steps per cycle of the torque curve.

 

Assuming that the torque versus angular position curve is a good approximation of a sinusoid, as long as the torque remains below the holding torque of the motor, the rotor will remain within 1/4 period of the equilibrium position. For a two-winding permanent magnet or hybrid motor, this means the rotor will remain within one step of the equilibrium position.

 

With no power to any of the motor windings, the torque does not always fall to zero! In variable reluctance stepping motors, residual magnetization in the magnetic circuits of the motor may lead to a small residual torque, and in permanent magnet and hybrid stepping motors, the combination of pole geometry and the permanently magnetized rotor may lead to significant torque with no applied power.

 

The residual torque in a permanent magnet or hybrid stepping motor is frequently referred to as the cogging torque or detent torque of the motor because a naive observer will frequently guess that there is a detent mechanism of some kind inside the motor. The most common motor designs yield a detent torque that varies sinusoidally with rotor angle, with an equilibrium position at every step and an amplitude of roughly 10% of the rated holding torque of the motor, but a quick survey of motors from one manufacturer (Phytron) shows values as high as 23% for one very small motor to a low of 2.6% for one mid-sized motor.

 

 

Half-Stepping and Micro stepping

 

So long as no part of the magnetic circuit saturates, powering two motor windings simultaneously will produce a torque versus position curve that is the sum of the torque versus position curves for the two motor windings taken in isolation. For a two-winding permanent magnet or hybrid motor, the two curves will be S radians out of phase, and if the currents in the two windings are equal, the peaks and valleys of the sum will be displaced S/2 radians from the peaks of the original curves, as shown in Figure 2.2:

 

Figure 2.2

This is the basis of half-stepping. The two-winding holding torque is the peak of the composite torque curve when two windings are carrying their maximum rated current. For common two-winding permanent magnet or hybrid stepping motors, the two-winding holding torque will be:

h2 = 20.5 h1

where:

h1 -- single-winding holding torque

h2 -- two-winding holding torque

 

This assumes that no part of the magnetic circuit is saturated and that the torque versus position curve for each winding is an ideal sinusoid.

 

Most permanent-magnet and variable-reluctance stepping motor data sheets quote the two-winding holding torque and not the single-winding figure; in part, this is because it is larger, and in part, it is because the most common full-step controllers always apply power to two windings at once.

 

If any part of the motor's magnetic circuits is saturated, the two torque curves will not add linearly. As a result, the composite torque will be less than the sum of the component torques and the equilibrium position of the composite may not be exactly S/2 radians from the equilibria of the original.

 

Microstepping allows even smaller steps by using different currents through the two motor windings, as shown in Figure 2.3:

 

Figure 2.3

For a two-winding variable reluctance or permanent magnet motor, assuming nonsaturating magnetic circuits, and assuming perfectly sinusoidal torque versus position curves for each motor winding, the following formula gives the key characteristics of the composite torque curve:

h = ( a2 + b2 )0.5

x = ( S / (/2) ) arctan( b / a )

Where:

a -- torque applied by winding with equilibrium at 0 radians.

b -- torque applied by winding with equilibrium at S radians.

h -- holding torque of composite.

x -- equilibrium position, in radians.

S -- step angle, in radians.

 

In the absence of saturation, the torques a and b are directly proportional to the currents through the corresponding windings. It is quite common to work with normalized currents and torques, so that the single-winding holding torque or the maximum current allowed in one motor winding is 1.0.

 

Friction and the Dead Zone

 

The torque versus position curve shown in Figure 2.1 does not take into account the torque the motor must exert to overcome friction! Note that frictional forces may be divided into two large categories, static or sliding friction, which requires a constant torque to overcome, regardless of velocity, and dynamic friction or viscous drag, which offers a resistance that varies with velocity. Here, we are concerned with the impact of static friction. Suppose the torque needed to overcome the static friction on the driven system is 1/2 the peak torque of the motor, as illustrated in Figure 2.4.

 

Figure 2.4

The dotted lines in Figure 2.4 show the torque needed to overcome friction; only that part of the torque curve outside the dotted lines is available to move the rotor. The curve showing the available torque as a function of shaft angle is the difference between these curves, as shown in Figure 2.5:

Figure 2.5

Note that the consequences of static friction are twofold. First, the total torque available to move the load is reduced, and second, there is a dead zone about each of the equilibria of the ideal motor. If the motor rotor is positioned anywhere within the dead zone for the current equilibrium position, the frictional torque will exceed the torque applied by the motor windings, and the rotor will not move. Assuming an ideal sinusoidal torque versus position curve in the absence of friction, the angular width of these dead zones will be:

d = 2 ( S / (/2) ) arcsin( f / h ) = ( S / (/4) ) arcsin( f / h )

where:

d -- width of dead zone, in radians

S -- step angle, in radians

f -- torque needed to overcome static friction

h -- holding torque

 

The important thing to note about the dead zone is that it limits the ultimate positioning accuracy! For the example, where the static friction is 1/2 the peak torque, a 90° per step motor will have dead-zones 60° wide! That means that successive steps may be as large as 150° and as small as 30°, depending on where in the dead zone the rotor stops after each step!

 

The presence of a dead zone has a significant impact on the utility of microstepping! If the dead zone is x° wide, then microstepping with a step size smaller than x° may not move the rotor at all. Thus, for systems intended to use high resolution microstepping, it is very important to minimize static friction.

 

Dynamics

Each time you step the motor, you electronically move the equilibrium position S radians. This moves the entire curve illustrated in Figure 2.1 a distance of S radians, as shown in Figure 2.6:

 

Figure 2.6

The first thing to note about the process of taking one step is that the maximum available torque is at a minimum when the rotor is halfway from one step to the next. This minimum determines the running torque, the maximum torque the motor can drive as it steps slowly forward. For common two-winding permanent magnet motors with ideal sinusoidal torque versus position curves and holding torque h, this will be h/(20.5). If the motor is stepped by powering two windings at a time, the running torque of an ideal two-winding permanent magnet motor will be the same as the single-winding holding torque.

It shoud be noted that at higher stepping speeds, the running torque is sometimes defined as the pull-out torque. That is, it is the maximum frictional torque the motor can overcome on a rotating load before the load is pulled out of step by the friction. Some motor data sheets define a second torque figure, the pull-in torque. This is the maximum frictional torque that the motor can overcome to accelerate a stopped load to synchronous speed. The pull-in torques documented on stepping motor data sheets are of questionable value because the pull-in torque depends on the moment of inertia of the load used when they were measured, and few motor data sheets document this!

 

In practice, there is always some friction, so after the equilibrium position moves one step, the rotor is likely to oscillate briefly about the new equilibrium position. The resulting trajectory may resemble the one shown in Figure 2.7:

 

 

 

 

Figure 2.7

 

Here, the trajectory of the equilibrium position is shown as a dotted line, while the solid curve shows the trajectory of the motor rotor.

 

Resonance

 

The resonant frequency of the motor rotor depends on the amplitude of the oscillation; but as the amplitude decreases, the resonant frequency rises to a well-defined small-amplitude frequency. This frequency depends on the step angle and on the ratio of the holding torque to the moment of inertia of the rotor. Either a higher torque or a lower moment will increase the frequency!

 

Formally, the small-amplitude resonance can be computed as follows: First, recall Newton's law for angular acceleration:

 

T = µ A

Where:

T -- torque applied to rotor

µ -- moment of inertia of rotor and load

A -- angular acceleration, in radians per second per second

We assume that, for small amplitudes, the torque on the rotor can be approximated as a linear function of the displacement from the equilibrium position. Therefore, Hooke's law applies:

T = -k 

where:

k -- the "spring constant" of the system, in torque units per radian

 -- angular position of rotor, in radians

We can equate the two formulas for the torque to get:

µ A = -k 

Note that acceleration is the second derivitive of position with respect to time:

A = d2/dt2

so we can rewrite this the above in differential equation form:

d2/dt2 = -(k/µ) 

To solve this, recall that, for:

f( t ) = a sin bt

The derivitives are:

df( t )/dt = ab cos bt

d2f( t )/dt2 = -ab2 sin bt = -b2 f(t)

Note that, throughout this discussion, we assumed that the rotor is resonating. Therefore, it has an equation of motion something like:

 = a sin (2 f t)

a = angular amplitude of resonance

f = resonant frequency

This is an admissable solution to the above differential equation if we agree that:

b = 2 f

b2 = k/µ

Solving for the resonant frequency f as a function of k and µ, we get:

f = ( k/µ )0.5 / 2

 

It is crucial to note that it is the moment of inertia of the rotor plus any coupled load that matters. The moment of the rotor, in isolation, is irrelevant! Some motor data sheets include information on resonance, but if any load is coupled to the rotor, the resonant frequency will change!

In practice, this oscillation can cause significant problems when the stepping rate is anywhere near a resonant frequency of the system; the result frequently appears as random and uncontrollable motion.

 

Resonance and the Ideal Motor

 

Up to this point, we have dealt only with the small-angle spring constant k for the system. This can be measured experimentally, but if the motor's torque versus position curve is sinusoidal, it is also a simple function of the motor's holding torque. Recall that:

 

T = -h sin( ((/2)/S)  )

The small angle spring constant k is the negative derivitive of T at the origin.

k = -dT / d = - (- h ((/2)/S) cos( 0 ) ) = (/2)(h / S)

Substituting this into the formula for frequency, we get:

f = ( (/2)(h / S) / µ )0.5 / 2 = ( h / ( 8 µ S ) )0.5

Given that the holding torque and resonant frequency of the system are easily measured, the easiest way to determine the moment of inertia of the moving parts in a system driven by a stepping motor is indirectly from the above relationship!

µ = h / ( 8 f2 S )

For practical purposes, it is usually not the torque or the moment of inertia that matters, but rather, the maximum sustainable acceleration that matters! Conveniently, this is a simple function of the resonant frequency! Starting with the Newton's law for angular acceleration:

A = T / µ

We can substitute the above formula for the moment of inertia as a function of resonant frequency, and then substitute the maximum sustainable running torque as a function of the holding torque to get:

A = ( h / ( 20.5 ) ) / ( h / ( 8 f2 S ) ) = 8 S f2 / (20.5)

Measuring acceleration in steps per second squared instead of in radians per second squared, this simplifies to:

Asteps = A / S = 8 f2 / (20.5)

Thus, for an ideal motor with a sinusoidal torque versus rotor position function, the maximum acceleration in steps per second squared is a trivial function of the resonant frequency of the motor and rigidly coupled load!

For a two-winding permanent-magnet or variable-reluctance motor, with an ideal sinusoidal torque-versus-position characteristic, the two-winding holding torque is a simple function of the single-winding holding torque:

 

h2 = 20.5 h1

Where:

h1 -- single-winding holding torque

h2 -- two-winding holding torque

Substituting this into the formula for resonant frequency, we can find the ratios of the resonant frequencies in these two operating modes:

f1 = ( h1 / ... )0.5

f2 = ( h2 / ... )0.5 = ( 20.5 h1 / ... )0.5 = 20.25 ( h1 / ... )0.5 = 20.25 f1 = 1.189... f1

This relationship only holds if the torque provided by the motor does not vary appreciably as the stepping rate varies between these two frequencies.

In general, as will be discussed later, the available torque will tend to remain relatively constant up until some cutoff stepping rate, and then it will fall. Therefore, this relationship only holds if the resonant frequencies are below this cutoff stepping rate. At stepping rates above the cutoff rate, the two frequencies will be closer to each other!

 

 

Living with Resonance

 

If a rigidly mounted stepping motor is rigidly coupled to a frictionless load and then stepped at a frequency near the resonant frequency, energy will be pumped into the resonant system, and the result of this is that the motor will literally lose control. There are three basic ways to deal with this problem:

 

Controlling resonance in the mechanism

 

Use of elastomeric motor mounts or elastomeric couplings between motor and load can drain energy out of the resonant system, preventing energy from accumulating to the extent that it allows the motor rotor to escape from control. Or, viscous damping can be used. Here, the damping will not only draw energy out of the resonant modes of the system, but it will also subtract from the total torque available at higher speeds. Magnetic eddy current damping is equivalent to viscous damping for our purposes.

 

Figure 2.8 illustrates the use of elastomeric couplings and viscous damping in two typical stepping motor applications, one using a lead screw to drive a load, and the other using a tendon drive:

 

Figure 2.8

In Figure 2.8, elastomeric moter mounts are shown at a and elastomeric couplings between the motor and load are shown at b and c. The end bearing for the lead screw or tendon, at d, offers an opportunity for viscous damping, as do the ways on which the load slides, at e. Even the friction found in sealed ball bearings or Teflon on steel ways can provide enough damping to prevent resonance problems.

 

Controlling resonance in the low-level drive circuitry

 

A resonating motor rotor will induce an alternating current voltage in the motor windings. If some motor winding is not currently being driven, shorting this winding will impose a drag on the motor rotor that is exactly equivalent to using a magnetic eddy current damper.

 

If some motor winding is currently being driven, the AC voltage induced by the resonance will tend to modulate the current through the winding. Clamping the motor current with an external inductor will counteract the resonance. Schemes based on this idea are incorporated into some of the drive circuits illustrated in later sections of this tutorial.

 

Controlling resonance in the high-level control system

 

The high level control system can avoid driving the motor at known resonant frequencies, accelerating and decelerating through these frequencies and never attempting sustained rotation at these speeds.

 

Recall that the resonant frequency of a motor in half-stepped mode will vary by up to 20% from one half-step to the next. As a result, half-stepping pumps energy into the resonant system less efficiently than full stepping. Furthermore, when operating near these resonant frequencies, the motor control system may preferentially use only the two-winding half steps when operating near the single-winding resonant frequency, and only the single-winding half steps when operating near the two-winding resonant frequency. Figure 2.9 illustrates this:

 

Figure 2.9

 

The darkened curve in Figure 2.9 shows the operating torque achieved by a simple control scheme that delivers useful torque over a wide range of speeds despite the fact that the available torque drops to zero at each resonance in the system. This solution is particularly effective if the resonant frequencies are sharply defined and well separated. This will be the case in minimally damped systems operating well below the cutoff speed defined in the next section.

 

Torque versus Speed

 

An important consideration in designing high-speed stepping motor controllers is the effect of the inductance of the motor windings. As with the torque versus angular position information, this is frequently poorly documented in motor data sheets, and indeed, for variable reluctance stepping motors, it is not a constant! The inductance of the motor winding determines the rise and fall time of the current through the windings. While we might hope for a square-wave plot of current versus time, the inductance forces an exponential, as illustrated in Figure 2.10:

 

Figure 2.10

               

The details of the current-versus-time function through each winding depend as much on the drive circuitry as they do on the motor itself! It is quite common for the time constants of these exponentials to differ. The rise time is determined by the drive voltage and drive circuitry, while the fall time depends on the circuitry used to dissipate the stored energy in the motor winding.

At low stepping rates, the rise and fall times of the current through the motor windings has little effect on the motor's performance, but at higher speeds, the effect of the inductance of the motor windings is to reduce the available torque, as shown in Figure 2.11:

 

Figure 2.11

The motor's maximum speed is defined as the speed at which the available torque falls to zero. Measuring maximum speed can be difficult when there are resonance problems, because these cause the torque to drop to zero prematurely. The cutoff speed is the speed above which the torque begins to fall. When the motor is operating below its cutoff speed, the rise and fall times of the current through the motor windings occupy an insignificant fraction of each step, while at the cutoff speed, the step duration is comparable to the sum of the rise and fall times. Note that a sharp cutoff is rare, and therefore, statements of a motor's cutoff speed are, of necessity, approximate.

The details of the torque versus speed relationship depend on the details of the rise and fall times in the motor windings, and these depend on the motor control system as well as the motor. Therefore, the cutoff speed and maximum speed for any particular motor depend, in part, on the control system! The torque versus speed curves published in motor data sheets occasionally come with documentation of the motor controller used to obtain that curve, but this is far from universal practice!

 

Similarly, the resonant speed depends on the moment of inertia of the entire rotating system, not just the motor rotor, and the extent to which the torque drops at resonance depends on the presence of mechanical damping and on the nature of the control system. Some published torque versus speed curves show very clear resonances without documenting the moment of inertia of the hardware that may have been attached to the motor shaft in order to make torque measurements.

 

The torque versus speed curve shown in Figure 2.11 is typical of the simplest of control systems. More complex control systems sometimes introduce electronic resonances that act to increase the available torque above the motor's low-speed torque. A common result of this is a peak in the available torque near the cutoff speed.

 

About the Author

Assistant professor in lord venkateswara engineering college.I am doing phd in sathyabama university, Tamil Nadu,India.

How does torque change as the motor shaft rotates on a DC Motor?

I need to know how torque changes throughout one full 360 degree rotation of the armature/shaft of a DC motor. (Torque vs. Angle Position)

To answer this you have to specify how many poles there are on the motor. The result on a 2 pole motor is much different from a 12 pole.

BMR Adjustable Torque Arm Pinion Angle How To

Drive Micrometer

Hard Disk Doesn’t Spin Up

A hard disk is comprised of several disk-shaped platters that rotate rapidly mounted on a shaft. These platters are magnetically coated with a similar material that is used magnetic recording tape. If not exposed to external conditions like temperature, water, vibrations etc, hard disk can remain functional for a long time. However, if it already suffers manufacturing faults, hard disk may crash unexpectedly. Hard disk contains a set of moving parts and that’s why, it has high odds to get wear out. In all such cases, Hard Drive Data Recovery experts come to rescue. They can extract lost information from such physically damaged hard drives using advanced tools and procedures.

Consider a situation, you power on the system and hard disk fails to spin up. Possible reasons could be:

Spindle motor is crashed: Hard disk spindle motor provides power to platters so that they may spin up. They allow them to rotate. It can get crashed if hard disk suffers high intensity shocks. A hard disk with crashed pindle motor can’t spin up. It can also happen if shaft is damaged or twisted

Head crash: Read/write head is the moving component that is responsible for accessing data from  hard drive recovery software . It floats at micrometer distance from platters’ surface. If one or more heads get crashed over this surface, they may prevent platters to spin up.

Logic board is damaged: Logic board is the circuitry that controls all hard disk internals. Due to short circuits and unexpected power failure, it may get damaged. In such cases, hard disk doesn’t get power and fails to spin up.

If you observe that hard drive is not spinning up, verify that power cable is properly attached and is in good condition first. If you find it correct, then probably your hard disk is physically damaged. You need to turn off the system immediately and use anti-static and shock-proof material to pack it and send to a  hard drive recovery service center. In this recovery service, experts deal with physically failed hard drive to extract lost data. Hard Drive Data Recovery experts follow some standard and advanced recovery techniques, like replacing or repairing damaged internals, displacing misaligned platters etc.

Stellar Information Systems Limited offers industry’s leading Hard Drive Recovery service for all sorts of physically damaged hard drives. It is offered through Class 100 Clean Rooms. Stellar provides complete and confidential disk recovery service for all makes of hard drives, including SCSI, SATA, IDE and EIDE.

About the Author

Simpson Raid is a freelancer for Stellar which offers data recovery software and file recovery programs for different OS and file system.

For mechs that know torque wrenches, which would you buy & trust?

Snapon
Torque Wrench, Adj. Click-type, U.S., Compact-Ratchet, 40-200 in. lb., 3/8" drive

http://buy1.snapon.com/catalog/item.asp?P65=&tool=hand&item_ID=55249&group_ID=953&store=snapon-store&dir=catalog

Sears
GearWrench Micrometer Torque Wrench 1/4" Drive 30-200 inch pounds

http://www.sears.com/shc/s/p_10153_12605_00993097000P?vName=Automotive&keyword=%22torque+wrench%22

This is primarily for a Yamaha motorcycle
Was also considering a Stanley Proto thats miltary grade...

http://www.stanleyproto.com/default.asp?CATEGORY=MICROMETER+TORQUE+WRENCHES&TYPE=PRODUCT&PARTNUMBER=J6061CX&strSiteName=PROTO&strDefaultCatalog=PROTO&SDesc=1%2F4%26quot%3B+Drive+40+-+200+in%2Flb.+Fixed+Head+Micrometer+Torque+Wrench

I just spent $800 upgrading my torque wrenches. I bought the Tech Angle Snap-ON 3/8" and 1/2" Most modern cars have torque to this spec then torque to this spec loosen all the bolts torque to this spec and then draw 90 degrees and 75 degrees to stretch the bolts Tech Angle will do that + or- 1 degree. And you will want to replace the fasteners when they measure to thin in the specified area. So you will need a good digital caliper too. Just depends what your doing and how often you build engines. Torquing wheels and suspension bolts Go with Sears. I remove the battery's when my tech angle are in there boxes. No leaky battery is going to ruin My 400 dollar wrench x 2

Standard Paper Box Machine 28" x 38" die cutter

Torque Wrench

How to attach a torque wrench to an external bottom bracket?

I'm replacing the bottom bracket on my bike with an external one and the instructions advise using a torque wrench to install it. What I don't know how to do is attach the wrench to the bottom bracket so that I can use the torque settings? Can anyone help?

Forget the torque wrench and tighten the bolt or nut with a rachet or wrench handle one foot long. Then if you push or pull with a 20 pound force on the handle, you'll get 20 foot pounds. Many bolts and nuts don't allow the use of torque wrenches because you can't get the torque wrench in there to tighten them! However, make sure not to over tighten to the point of breaking the bolt or stud off.

Car Maintenance Tips : How to Use a Torque Wrench

Square Torque

Men's Jewellery - Focus on Fred Bennett Jewellery

Men's Jewellery has come into its own in the last few years. There has been a move away from the bling bling culture of the nineties and now there are stylish, subtle pieces of jewellery for men that are far more appealing. Style for men has developed a more refined attitude than it had. Many men are now choosing to own a signature piece of jewellery. Jewellery for men tends to be designed around a small selection of styles with subtle variations. For example the dog tag, worn by celebrities such as Justin Timberlake and Jamie Foxx. Military in origin dog tags are masculine expressions of style. Different tags made by designers like Hot Diamonds, Fred Bennett or Police have enough individuality to create a different look whilst adhering to the masculine stereotypes fostered by the military association.

Fred Bennett Jewellery is a collection that is inspired by a combination of classic and contemporary design. Smooth lines and clean design characterise the collection, but it is by no means a dull range of jewellery. The Fred Bennett range is drawn together in the centre of fashionable London, the designers are superbly placed to take advantage of the city's influential fashion scene. The artistic vibrancy of the city is evident in the Fred Bennett jewellery collection; the range is full of texture and interesting shapes that draw the eye and give the wearer a unique style.

Two of the most popular pieces of Fred Bennett Jewellery are the black woven leather magnetic clasp bracelet and the highly polished squared torque bangle. Both pieces reflect the essential masculinity of the collection whilst being part of modern style which is right on trend. The Fred Bennett range also has a selection of men's sterling silver jewellery. Precious metal jewellery has lasting value and the designs in silver are not created to be disposable fashion. The great designs have lasting appeal and include a diamond set ID bracelet and a scratched finished cross pendant.

Designer men's jewellery is popular right now, Fred Bennett is an up and coming brand name that is swiftly building up an army of followers. The diverse range ensures that there is something for every man including cuff links, necklaces, bracelets and bangles.

Another range to look out for is the iconic Police jewellery range. Police have been at the forefront of style for two decades, with high profile brand ambassadors such as David Beckham, Bruce Willis, Anotonio Banderas and George Clooney. There unusual collection of jewellery is designed for people who are unique.

About the Author

Amy works for Find Jewellery we have a stylish selection of Fred Bennett Jewellery and a great range of other jewellery for men and women.

Help explaining a behavior of a material?

Assuming that they have the same total cross sectional area, which should be better able to resit an applied torque: a) a round bar or, b) a square bar of the same material?

Symmetry, I think, favors the round bar without even thinking about it. But thinking about it....

If both have the same total cross sectional area, then the corners of the square will protrude outside of the round, but its sides will pass inside of the round. Now, since the corners of the square are "broken" every 90 degrees, it seems to me that every part of the square that is outside of the largest circle that can be inscribed will not contribute to torque capacity. In other words, the torque capacity of the square is equal to that of a round rod of the same material which has a diameter equal to the length of a side of the square. And since that rod would be smaller in diameter than the round which has the same total cross sectional area, would be weaker.

rapidtorc square drive hydraulic torque wrench

Torque Drive

How To Handle a Skid in a Front Wheel Drive Car

The majority of cars nowadays are front wheel drive. This is because they are both mechanically easier to design and dynamically the handling is regarded as more benign, in the event that the driver enters a skid. In essence, there are three ways a driver can skid the wheels, whilst accelerating, under braking or during cornering and the recovery from each does differ.

Skidding a front wheel drive car under acceleration
If the road surface is slippery, due to ice or rain, or you have applied excessive throttle, then the front wheels are very likely to skid. In high powered front wheel drive cars this can also result in the steering wheel tugging in either direction making the car hard to hold steady in a straight line, and this is known as torque steer.

To prevent the wheels from spinning in this situation you need to gently lift off the throttle, the front wheels will regain traction and forward drive is restored. This type of skid is normally avoidable and can be anticipated if for example, you are pulling out of an uphill junction and the road is wet or if there is snow on the road. However, if you are on ice and the level of grip is very low it would be better to attempt to pull away in second gear by slipping the clutch slightly. This should reduce the torque through the front wheels and give you better traction.

Skidding a front wheel drive under braking
If you lock the front wheels up under heavy braking then your ability to steer will be lost and, if this occurs on ice or slippery roads, so will your ability to slow down. To come out of the skid gently release the brake pedal until the skid stops and the front wheels start turning again then reapply the brakes using less force.

Normally there will be no need for the procedure above as most modern road cars are fitted with antilock braking systems called ABS, which will carry out the same process hundreds of times a second, so that you can maintain steering control whilst under heavy braking. This is normally felt as a judder through the brake pedal accompanied by a loud graunching noise. Whilst ABS is an important safety aid it can't work miracles and it will still take longer to stop on a wet road than on a dry one.

Skidding a front wheel drive car whilst cornering, causing understeer
When cornering a front wheel drive car, the front wheels have to cope both with supplying the power and applying a turning force. If you enter a corner too fast, the front wheels will lose grip and start to skid, this problem is more likely to occur at night, where the light from your car headlight bulbs may not show up the tightening radius curve of a bend. The car will want to carry straight on regardless of how much steering input you use, and this effect is called understeer.

Often when an inexperienced driver feels their car start to understeer they will panic and try to resolve the problem by braking harshly. This will only worsens the understeer, and makes you more likely to plough on into the path of an oncoming car or straight off the road and into a hedge. You must avoid this temptation to brake aggressively and instead if you start to feel the car understeer gently lift off the throttle, grip will return and the steering will take effect again.

Skidding a front wheel drive car whilst cornering, causing oversteer
There is one other type of skid that can occur to a front wheel drive car when cornering, and that is called oversteer. It is very rare for a road driver to experience this type of skid, as oversteer will normally only occur at very high cornering speeds, when the driver has sharply lifted off the throttle mid way through the corner. When a car is oversteering the back wheels slide out towards the outside of the turn, and this is counteracted in a front wheel drive car by pressing hard down on the throttle which will pull the vehicle out of the slide.

Whilst it may seem more natural to depress the brake if a front wheel drive car is oversteering this would be serious mistake. Braking would place more weight over the front wheels of the car, causing the rear wheels to skid more, the oversteer will worsen and it is very likely that you will spin off the road and into the nearest hedge backwards.

About the Author

Jo Alexander is an online, freelance journalist and keen windsurfer. Jo lives by the sea in Essex.

CAN YOU DRIVE A CAR WITH A BAD TORQUE CONVERTER?

I have read all of the symptoms of a bad torque converter and it seems to be describing my 96 honda civic to a tee. My biggest concern is can i continue to drive it?

your torque converter only makes a connection between the engine and transmission.if it fails then you have no Go.it replaces the clutch.so if your clutch burns out `you have no Go also.

drive by wire with torque feed back