I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer. My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!


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On 12/08/17 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer.

The results of not going to that have been fixed by me more than once.

My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Hire a bigger torque wernch. I ended up borrowing one and putting some
scaffold over the end to get more leverage as I jumped off te car bumper.




--
Religion is regarded by the common people as true, by the wise as
foolish, and by the rulers as useful.

(Seneca the Younger, 65 AD)

There should be an equation where a longer extension on that existing wrench
would make it torque more. I have this misty memory of something like this,
but it was a long while ago now
Brian

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On 12/08/17 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer.

The results of not going to that have been fixed by me more than once.

My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Hire a bigger torque wernch. I ended up borrowing one and putting some
scaffold over the end to get more leverage as I jumped off te car bumper.




--
Religion is regarded by the common people as true, by the wise as foolish,
and by the rulers as useful.

(Seneca the Younger, 65 AD)

On 12/08/2017 11:34, Cursitor Doom wrote:
I need to do up a bolt (crankshaft pully) to 220ft/lb,

Chuck the old VW flat 4 on the nearest scrapheap and
buy something modern ?.

Or use a torque multiplier.

Or do what garage 'mechanics' do, just use an
air gun with an impact socket and blast away
at it, then finish with a four foot long bar.

On Saturday, 12 August 2017 11:38:48 UTC+1, Cursitor Doom wrote:
I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer. My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

220ftlb is 220lbs at 1', 110lbs at 2', 55lbs at 4'. You don't need a torque wrench at all.


NT

On Sat, 12 Aug 2017 12:34:01 +0100, Tim+ wrote:

Probably not going to be possible with an in situ engine though.
Better to hire or borrow appropriate tool.

....or just use loads of Locktite.

On 12/08/2017 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer. My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the

There are ways of doing that sum, but it not straight forward. Basically
you can calculate the clamping pressure exerted by the faster if you
know a bunch of things like the bolt head diameter, the pitch of the
thread, the modulus of elasticity of the fastener, and the coefficient
of friction in the interface between fastener and what you are
fastening. Then you could work out the relationship between rotation
angle and stretch, and between stretch in the fastener and applied
clamping force.

required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Alternative approaches would include using an extension on the *output*
side of the torque wrench. i.e. use the wrench's indicator to measure
the torque applied to the extension, and then calculate the torque
applied to the fastening, using the ratio of the lengths of the wrench
and the extension. An example he

https://www.norbar.com/en-gb/Home/To...ion-Calculator

Or if you have a way of measuring the pull applied to the end of the
bar, extend that, and just use force applied multiplied by the bar
length to get a direct measure of the torque you are applying. e.g. 50
lbs of pull on a 5' bar would give 250 lbs.ft


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Saturday, 12 August 2017 14:05:36 UTC+1, John Rumm wrote:
On 12/08/2017 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not

there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Alternative approaches would include using an extension on the *output*
side of the torque wrench. i.e. use the wrench's indicator to measure
the torque applied to the extension, and then calculate the torque
applied to the fastening, using the ratio of the lengths of the wrench
and the extension. An example he

https://www.norbar.com/en-gb/Home/To...ion-Calculator

Or if you have a way of measuring the pull applied to the end of the
bar, extend that, and just use force applied multiplied by the bar
length to get a direct measure of the torque you are applying. e.g. 50
lbs of pull on a 5' bar would give 250 lbs.ft

bathroom scales


NT

wrote:
On Saturday, 12 August 2017 14:05:36 UTC+1, John Rumm wrote:
On 12/08/2017 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not

there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Alternative approaches would include using an extension on the *output*
side of the torque wrench. i.e. use the wrench's indicator to measure
the torque applied to the extension, and then calculate the torque
applied to the fastening, using the ratio of the lengths of the wrench
and the extension. An example he

https://www.norbar.com/en-gb/Home/To...ion-Calculator

Or if you have a way of measuring the pull applied to the end of the
bar, extend that, and just use force applied multiplied by the bar
length to get a direct measure of the torque you are applying. e.g. 50
lbs of pull on a 5' bar would give 250 lbs.ft

bathroom scales


NT


Or, many people have luggage scales for when they don't want check-in
problems.

On 8/12/2017 11:34 AM, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer. My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!


Well there *are* some calcs which could be done, but in this case I
would take a much simpler approach. You know how heavy you are. Stick a
suitable scaffold pole over a suitable spanner, and apply your weight at
the appropriate distance. You just need to place one foot there, and
lift yourself off the ground. Try not to bounce too much.

On Sat, 12 Aug 2017 21:19:14 +0100, newshound wrote:

Well there *are* some calcs which could be done, but in this case I
would take a much simpler approach. You know how heavy you are. Stick a
suitable scaffold pole over a suitable spanner, and apply your weight at
the appropriate distance.

Yeah, but I only want to apply 220ft/lbs., not shear the head off in a
microsecond. ;-)




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This message may be freely reproduced without limit or charge only via
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On 12/08/2017 15:16, wrote:
On Saturday, 12 August 2017 14:05:36 UTC+1, John Rumm wrote:
On 12/08/2017 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not

there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Alternative approaches would include using an extension on the *output*
side of the torque wrench. i.e. use the wrench's indicator to measure
the torque applied to the extension, and then calculate the torque
applied to the fastening, using the ratio of the lengths of the wrench
and the extension. An example he

https://www.norbar.com/en-gb/Home/To...ion-Calculator

Or if you have a way of measuring the pull applied to the end of the
bar, extend that, and just use force applied multiplied by the bar
length to get a direct measure of the torque you are applying. e.g. 50
lbs of pull on a 5' bar would give 250 lbs.ft

bathroom scales

That was my immediate thought too. Bathroom scales and a long bar of a
known length on a wrench.

If this was a once only tighten, I might consider say 45degs of
additional turn to put the bolt into the plastic range after torquing to
150ftlbs.

Alternatively, perhaps noting the amount of turn, from 50 to 100, and
100 to 150. From 150 to 220ftlbs ought to be proportional(ish).

On 8/12/2017 10:00 PM, Cursitor Doom wrote:
On Sat, 12 Aug 2017 21:19:14 +0100, newshound wrote:

Well there *are* some calcs which could be done, but in this case I
would take a much simpler approach. You know how heavy you are. Stick a
suitable scaffold pole over a suitable spanner, and apply your weight at
the appropriate distance.

Yeah, but I only want to apply 220ft/lbs., not shear the head off in a
microsecond. ;-)




Can't remember the numbers, but last time I needed something out of
range of my biggest torque wrench (18 inch long, 1/2 square drive) it
was a couple of feet of scaffold pole. Long time ago.

:-)

On 12/08/2017 22:00, Cursitor Doom wrote:
On Sat, 12 Aug 2017 21:19:14 +0100, newshound wrote:

Well there *are* some calcs which could be done, but in this case I
would take a much simpler approach. You know how heavy you are. Stick a
suitable scaffold pole over a suitable spanner, and apply your weight at
the appropriate distance.

Yeah, but I only want to apply 220ft/lbs., not shear the head off in a
microsecond. ;-)

I resemble that remark ;-)


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Saturday, August 12, 2017 at 10:08:14 PM UTC+1, Fredxxx wrote:
On 12/08/2017 15:16, wrote:
On Saturday, 12 August 2017 14:05:36 UTC+1, John Rumm wrote:
On 12/08/2017 11:34, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not

there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!

Alternative approaches would include using an extension on the *output*
side of the torque wrench. i.e. use the wrench's indicator to measure
the torque applied to the extension, and then calculate the torque
applied to the fastening, using the ratio of the lengths of the wrench
and the extension. An example he

https://www.norbar.com/en-gb/Home/To...ion-Calculator

Or if you have a way of measuring the pull applied to the end of the
bar, extend that, and just use force applied multiplied by the bar
length to get a direct measure of the torque you are applying. e.g. 50
lbs of pull on a 5' bar would give 250 lbs.ft

bathroom scales

That was my immediate thought too. Bathroom scales and a long bar of a
known length on a wrench.

If this was a once only tighten, I might consider say 45degs of
additional turn to put the bolt into the plastic range after torquing to
150ftlbs.

Alternatively, perhaps noting the amount of turn, from 50 to 100, and
100 to 150. From 150 to 220ftlbs ought to be proportional(ish).

Spring scales are what I used many moons ago. Something like what fishermen use might do

On Sat, 12 Aug 2017 22:08:16 +0100, Fredxxx wrote:

Alternatively, perhaps noting the amount of turn, from 50 to 100, and
100 to 150. From 150 to 220ftlbs ought to be proportional(ish).

I like your thinking. This would be unlikely to be a linear relationship,
so the results would best be graphed. It should be an excellent predictor
of the required full torque in terms of degrees of twist needed.
Thoroughly greasing the threads up first should also improve accuracy.
Probably the best answer so far IMO, although Tabby's was pretty neat,
too.

Thanks all!



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On Monday, 14 August 2017 23:38:12 UTC+1, Cursitor Doom wrote:
On Sat, 12 Aug 2017 22:08:16 +0100, Fredxxx wrote:

Alternatively, perhaps noting the amount of turn, from 50 to 100, and
100 to 150. From 150 to 220ftlbs ought to be proportional(ish).

I like your thinking. This would be unlikely to be a linear relationship,
so the results would best be graphed.

which is done by practical testing with known torques, thus doesn't solve the problem. And IME bolt tightening v torque is far from linear.

It should be an excellent predictor
of the required full torque in terms of degrees of twist needed.
Thoroughly greasing the threads up first should also improve accuracy.
Probably the best answer so far IMO, although Tabby's was pretty neat,
too.

I don't know of a reason to complicate what is a simple task.


NT

On 8/12/2017 11:34 AM, Cursitor Doom wrote:

I need to do up a bolt (crankshaft pully) to 220ft/lb, apparently. Not
really sure why it demands such a high figure, but I'm no mechanical
engineer. My torque wrench, which I thought was pretty big, 'only' goes
up to 150ft/lb, which I assumed would be plenty. How wrong I was.
The question is, is there a way tightening this bolt up to the required
220ft/lb by tightening to 150 then marking the bolt head and giving it a
further - for example - 90' of rotation? How does one arrive at the
required extra rotation figure (assuming this method even works) or is
there another better approach altogether? I'm not about to buy another
even bigger torque wrench just for one sodding bolt!!


For the real pedants, this isn't a bad analysis of the problem:

http://projekter.aau.dk/projekter/fi...s_of_bolts.pdf

Another reasonable treatment is given in a Handbook published by
Molykote in 1991, but unfortunately they don't seem to have ported it to
the web.

Basically, you have friction in two places: within the threads, and
underneath the head of the bolt. If you are designing something
complicated with multiple fasteners like a cylinder head or a helicopter
gearbox, it's worth going into the detail.

For a single bolt like a crankshaft pulley where you have been given a
target torque, just use a simple calculation. But the theory helps to
explain why you want clean and well lubricated surfaces for the threads,
and underneath the head of the bolt.

On Mon, 14 Aug 2017 16:18:11 -0700, tabbypurr wrote:

I don't know of a reason to complicate what is a simple task.


NT

OK, your suggestion wins. A ten shilling postal order is on its way.
;-)



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This message may be freely reproduced without limit or charge only via
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