what does "angle-tighten" mean?

[HolidayRoad]

Gents,

Can anyone explain the following: In my Haynes manual it says, ...do up the gearchange mechanism selector rod clamp bolt, stage 1, 12Nm, then through stage 2, "angle-tighten a further 225 degrees". ?????

[Trooper2]

This should explain better than I could

"ANGLE CONTROLLED TIGHTENING
A tightening procedure in which a fastener is first tightened by a pre-selected torque (called the snug torque) so that the clamped surfaces are pulled together, and then is further tightened by giving the nut an additional measured rotation. Frequently bolts are tightened beyond their yield point by this method in order to ensure that a precise preload is achieved. Bolts of short length can be elongated too much by this method and the bolt material must be sufficiently ductile to cater for the plastic deformation involved. Because of the bolt being tightened beyond yield, its re-use is limited."

Taken from here: http://www.boltscience.com/pages/glossary.htm

See also: http://www.robbos.com.au/myweb/Tech_Bolts.htm (scroll down)

This method of torquing is greatly aided by using a Torque Angle Gauge:

http://buy1.snapon.com/catalog/item.asp?item_ID=88...

You don't have to buy the expensive Snap-On, you should be able to find one for around £ 10.00 if you need one.

[HolidayRoad]

Thanks Trooper!

[tempus]

Hi,lazer tools do one for about a fiver,motorfactors should stock them.Tempus

[Boosted LS1]

tempus said:

Hi,lazer tools do one for about a fiver,motorfactors should stock them.Tempus

They're not that much cop though so be careful to zero them when starting the settings and I tension the wrench to take out the slack. That's before I went digital

Boosted.

[sirhc]

Prob a bit late to give you a worth while answer now, but here goes.
Consider you start tightening the bolt/nut at 12 o'clock & finish tightening at 12:37 1/2.
That would give you 225 degrees.
Just like working with a clock face.
90 degrees = 15 mins
180 degrees = 30 mins
270 degrees = 45 mins.

[That Daddy]

Oh is just a quick heads up mark all the bolts with paint at the 12 o,clock position(colour of your choice,faint line or dot)that way if the phone rings or the missus tells you your coffee is ready,you dont lose track of the bolts you have already stretched/angle tightened(i dont need to explain the consequence if you over do things with these bolts)it sounds obvious i know but when your in a busy workshop you cannot afford to make dumb mistakes like thateven more so when your building the bottom end of a seasoned unit.

[HolidayRoad]

Thanks everybody for the useful tech tips! Very helpful. I am in the process of replacing the gearlinkage on wife's Corsa (C)