Hookes Law

can we see a digital representation of this device?

datakoll said:

can we see a digital representation of this device?

the problem is? the tool samples a predetermined length of the spoke's
shaft and relates that specific length bit by the tool to the tool's
gauge
whereas hanging weight from a spoke twists the spoke's complete length
and twists the hub end.
what that does to the measurement ? is trial and error on your end
right?

Tosspot said:

Since I have acquired home bodged spoke tensiometer and a "conversion
chart", I was wondering if the conversion chart is accurate. So, I
reason, it should be easy enough so suspend a given volume of water from
a spoke and measure the deflection.

My question is this, can I get away with say 5,10,15 and 20 kgs (about a
bucket in 5 litre increments), or do I need to get closer to the 70-90kg
that a spoke experiences.

In short, is it linear?

no it's most definitely not. your tensiometer is testing a material in
3-point loading, with both tension and bending being factors. you
therefore need to be in the loading zone found in practice to have
accuracy - extrapolation for lower tensions is highly unreliable.

Quoted message said:

For those that are interested, the principle of the bodge job is the
same as the DT Tensio

http://www.dtswiss.com/index.asp?fuseaction=proline.bikedetail&id=8

but a bit (ok a lot) more Heath-Robinson

http://en.wikipedia.org/wiki/Heath_Robinson

jim beam said:

Tosspot said:

Since I have acquired home bodged spoke tensiometer and a "conversion
chart", I was wondering if the conversion chart is accurate. So, I
reason, it should be easy enough so suspend a given volume of water
from a spoke and measure the deflection.

My question is this, can I get away with say 5,10,15 and 20 kgs (about
a bucket in 5 litre increments), or do I need to get closer to the
70-90kg that a spoke experiences.

In short, is it linear?

no it's most definitely not. your tensiometer is testing a material in
3-point loading, with both tension and bending being factors. you
therefore need to be in the loading zone found in practice to have
accuracy - extrapolation for lower tensions is highly unreliable.

Thanks for that, I shall find a bigger bucket then!

Tosspot said:

jim beam said:

Tosspot said:

Since I have acquired home bodged spoke tensiometer and a "conversion
chart", I was wondering if the conversion chart is accurate. So, I
reason, it should be easy enough so suspend a given volume of water
from a spoke and measure the deflection.

My question is this, can I get away with say 5,10,15 and 20 kgs
(about a bucket in 5 litre increments), or do I need to get closer to
the 70-90kg that a spoke experiences.

In short, is it linear?

no it's most definitely not. your tensiometer is testing a material
in 3-point loading, with both tension and bending being factors. you
therefore need to be in the loading zone found in practice to have
accuracy - extrapolation for lower tensions is highly unreliable.

Thanks for that, I shall find a bigger bucket then!

what are you putting in the bucket? 100kg of water is quite a volume.
100kg of lead is not.

Quoted message said:

Tosspot said:

Thanks for that, I shall find a bigger bucket then!

jim beam said:

what are you putting in the bucket? 100kg of water is quite a volume.
100kg of lead is not.

Hell, sand would be a huge improvement over water. (wet sand even better)

I haven't tried this exercise but its widespread fersure as several
rube Goldberg devices ahhhh spring to mind. Yet I haven't read of
one ??? is there a website devoted to gearloose tensiometers? but off
course-at least 15 as of 9AM EDST

http://www.google.com/patents?spell=1&q=wire+tensiometer&btnG=Search+Patents
http://www.google.com/patents?id=W8AwAAAAEBAJ&dq=spoke+tensiometer

an unbendable "beam" holding a given spoke length and a fish scale
coordinated to the beama acquisition....

datakoll said:

I haven't tried this exercise but its widespread fersure as several
rube Goldberg devices ahhhh spring to mind. Yet I haven't read of
one ??? is there a website devoted to gearloose tensiometers? but off
course-at least 15 as of 9AM EDST

http://www.google.com/patents?spell=1&q=wire+tensiometer&btnG=Search+...http://www.google.com/patents?id=W8AwAAAAEBAJ&dq=spoke+tensiometer

an unbendable "beam" holding a given spoke length and a fish scale
coordinated to the beama acquisition....

AHHHH. do it backwards with a pull then release into the digital
readout!
the problem could be-designing to avoid grade 9 hardware

jim beam said:

Tosspot said:

jim beam said:

Tosspot wrote:

>
> Since I have acquired home bodged spoke tensiometer and a
> "conversion chart", I was wondering if the conversion chart is
> accurate. So, I reason, it should be easy enough so suspend a given
> volume of water from a spoke and measure the deflection.
>
> My question is this, can I get away with say 5,10,15 and 20 kgs
> (about a bucket in 5 litre increments), or do I need to get closer
> to the 70-90kg that a spoke experiences.
>
> In short, is it linear?

no it's most definitely not. your tensiometer is testing a material
in 3-point loading, with both tension and bending being factors. you
therefore need to be in the loading zone found in practice to have
accuracy - extrapolation for lower tensions is highly unreliable.

Thanks for that, I shall find a bigger bucket then!

what are you putting in the bucket? 100kg of water is quite a volume.
100kg of lead is not.

Well, I was thinking of water because it's easy to transport in a
hodepipe and easy to dispose of later. The current thinking is one of
those "IKEA Bags", which look waterproof and will certainly hold the weight.