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Terry
02-03-2010, 08:24 PM
http://www.glacern.net/free_photo_upload/MVC-725S.jpg
http://www.glacern.net/free_photo_upload/MVC-726S.jpg

It has a half inch drive in and half inch square out for maybe a socket.
Don't know what the wire clamp is for.
What is it for and how do you use it?

ligito
02-03-2010, 08:27 PM
A static clamp?

Black_Moons
02-03-2010, 08:36 PM
I think thats a torque rotation aid.
I seem to recall some bolts (head bolts on an engine?) that required to be torqued to a point, and then rotated another half turn or whatever.

the clamp would be used to make the guage stationary, and it looks like theres an indicator 'rod' sticking out of the center that rotates. as you tighten the bolt... letting you keep track of the rotation of the bolt even as you move your rachet back and forth.

cryptrx
02-03-2010, 08:55 PM
The only pieces on their site made in America?

- Bill

quadrod
02-03-2010, 08:55 PM
black moons has it right, it is an torque angle indicator. Lots of the automotive manufactures use plastic region bolts that are torqued to say 25 lbs and then an additional 90* and then an additional 90*.

jixxerbill
02-03-2010, 10:12 PM
black moons has it right, it is an torque angle indicator. Lots of the automotive manufactures use plastic region bolts that are torqued to say 25 lbs and then an additional 90* and then an additional 90*.
you r correct sir !!!

Ken_Shea
02-03-2010, 10:27 PM
Had never seen one of those, used a screwdriver to scratch a mark and fudged the 90.

tdkkart
02-03-2010, 10:45 PM
Harley specifies this type of torque procedure on it's current Twin Cam motors.

EddyCurr
02-03-2010, 10:59 PM
Lots of the automotive manufactures use plastic region bolts that are
torqued to say 25 lbs and then an additional 90* and then an additional 90*.These are known as Torque-To-Yield fasteners.

There may be exceptions, but generally, TTY fasteners are intended for
one-time use. They are to be replaced with new bolts, not used again.

Further reading: The secrets of bolt tightening (http://www.canadiandriver.com/2004/03/03/auto-tech-the-secrets-of-bolt-tightening.htm) by Jim Kerr.

.

Ken_Shea
02-03-2010, 11:18 PM
These are known as Torque-To-Yield fasteners.

There may be exceptions, but generally, TTY fasteners are intended for
one-time use. They are to be replaced with new bolts, not used again.

Further reading: The secrets of bolt tightening (http://www.canadiandriver.com/2004/03/03/auto-tech-the-secrets-of-bolt-tightening.htm) by Jim Kerr.

.

Also called stretch bolts. use just once is correct.

darryl
02-04-2010, 12:27 AM
Now that doesn't instill a whole lot of confidence- torque the bolts til they start to give way :)

winchman
02-04-2010, 04:08 AM
So, how are you supposed to know the difference between the stretch bolts and the regular kind once it's removed from where it was originally installed?

Is there a way to tell if they've already been stretched? Maybe paint on the shank that would show hairline cracks?

gnm109
02-04-2010, 07:43 AM
Harley specifies this type of torque procedure on it's current Twin Cam motors.


Yes. But they have used that method for a long time starting with the Evolution motors in 1984/85 on the cylinder head torque procedure. They get to a certain point and then give another set rotation in degrees.

More recently, on the Twin Cam engines as you say, they changed the procedure to tighten up the motor drive sprocket from a straight torque to something like 70 ft. lbs. followed by another set degree of rotation.

I'm guessing that the clamp on that tool would be used to hang it up somewhere so that it doesn't get lost.

Ken_Shea
02-04-2010, 08:17 AM
So, how are you supposed to know the difference between the stretch bolts and the regular kind once it's removed from where it was originally installed?

Is there a way to tell if they've already been stretched? Maybe paint on the shank that would show hairline cracks?

Don't know of any easily definable method.
They do seem to be smaller in diameter then conventional (automotive) head bolts but never deliberately compared them, however, it wouldn't surprise me if there was some form of marking stamped in them.

djinh
02-04-2010, 09:15 AM
So, how are you supposed to know the difference between the stretch bolts and the regular kind once it's removed from where it was originally installed?

Is there a way to tell if they've already been stretched? Maybe paint on the shank that would show hairline cracks?

When they've been stretched they'll usually be longer :)

The workshop manual will specify the bolt length limits.

But not mixing up the used and the new bolts when re-assembling an engine also helps of course...

Alex

digger_doug
02-04-2010, 10:02 AM
Now that doesn't instill a whole lot of confidence- torque the bolts til they start to give way :)


Well, to add to the complaint, I have heard, if when installing them,
one breaks, fish it out, and put in a new one at the same torque.

The little I've been exposed to them, and haging around the engineers,
the bolt will not see any ADDITIONAL load after you torque it.

Prestretching the bolt, loads the surrounding area into compression
(the area under the washer head) and this area is about 8 times
the cross sectional area of the bolt.

Until the load becomes so great that this area "unloads" it's
pre-loaded compressional load, there will be no change
(physical) in the length of the bolt, hence no load change.

In a head application (on a car engine) the repeated
explosion load from running, will not be seen by the bolt.

A soft head gasket, relaxing after years of being squished,
could allow the head to "unload" its compression load.

OR so I've been told....

form_change
02-04-2010, 03:01 PM
Torque-turn tightening of fasteners isn't just limited to the one time use as given above, it is also a legitimate way of ensuring the correct load on normal fasteners, alsthough they are not taken into the plastic region. The reasoning is that the fastener is there to increase the load between the two surfaces that they are clamping. Typically this is done by applying around 65% of the yield load. However, the load applied with a standard torque wrench will be around (from memory) around +/- 20% of the ideal load because of things like thread condition, thread lubrication, temperature, surface treatments and so on. For critical joints applying a small preload torque that is sufficient to bed the fastener and then an angle (60 or maybe 90 degrees) is far more accurate. Because of the helix angle of the thread the rotation can be reliably translated into a thread/ shank elongation (elastic region) that will then give a more repeatable clamp load, I think around+/- 5% (again from memory - all my good books are at work).
Michael

WaveDude
02-04-2010, 03:04 PM
The ultimate guide to apply to your torque wrench:

http://sheldonbrown.com/images/tork-calibration.gif

jixxerbill
02-04-2010, 08:12 PM
The ultimate guide to apply to your torque wrench:

http://sheldonbrown.com/images/tork-calibration.gif
i use a german torque to tighten things .......goodntight !!! lol
on a serious note most high-end drag racing motors use a bolt stretch guage. im not sure if thats what its called !!! ive seen it used on rod bolts, they will tighten the nut till the bolt reaches a certain length ....my .02

rolland
02-04-2010, 10:21 PM
The easy way is to tighten it a half turn before it strips. To find that strip it and back out a half turn.
Been there done that:eek:

S_J_H
02-05-2010, 09:34 AM
yep, a torque angle indicator. Cheapy tool. I have had that exact same tool for a long time. It has come in handy now and then.

Steve