Park tensiometer... Lubrication reduces readings by 20%

Basically that is it. I got the idea yesterday to lube (Dupont Teflon
lube) my 4 month old Park gauge yesterday, because I figured "what
could it hurt?". A spoke that previously measured 129kg (2 days ago)
now measures 105kg. A spoke that measured 102kg now measures 80kg.
Both are without tires, in case you were wondering.

Lubrication is probably a good thing, since if there is stiction in
the device that will reduce the consistency of the readings. My
question is... which one is likely to be correct? If they are
"calibrated" to include the stiction, then my readings are too low
now. A ~20% change is *not* small.

On Mar 24, 10:05 am, "Phil, Non-Squid"
wrote:
If you're certain, why not just turn the adjustment screw until your 129
measures 128kgf again?

That's the issue... I don't know which is correct. if the unit comes
unlubricated (seems to be the case with mine at least), and is
calibrated with significant stiction (maybe... maybe not... they don't
calibrate each device) then that would be an ok approach. But if they
calibrate them with stiction that can be easily removed with a little
lube, then I think their method is flawed. Stiction is not something
you want in a tensiometer anyway.

Ron Ruff wrote:
Basically that is it. I got the idea yesterday to lube (Dupont Teflon
lube) my 4 month old Park gauge yesterday, because I figured "what
could it hurt?". A spoke that previously measured 129kg (2 days ago)
now measures 105kg. A spoke that measured 102kg now measures 80kg.
Both are without tires, in case you were wondering.

Lubrication is probably a good thing, since if there is stiction in
the device that will reduce the consistency of the readings. My
question is... which one is likely to be correct? If they are
"calibrated" to include the stiction, then my readings are too low
now. A ~20% change is *not* small.

If you're certain, why not just turn the adjustment screw until your 129
measures 128kgf again? Check again with the 102 and if it matches then you
should be good. Now you just have to keep it lubed.
--
Phil

Ron Ruff wrote:
Basically that is it. I got the idea yesterday to lube (Dupont Teflon
lube) my 4 month old Park gauge yesterday, because I figured "what
could it hurt?". A spoke that previously measured 129kg (2 days ago)
now measures 105kg. A spoke that measured 102kg now measures 80kg.
Both are without tires, in case you were wondering.

Lubrication is probably a good thing, since if there is stiction in
the device that will reduce the consistency of the readings. My
question is... which one is likely to be correct? If they are
"calibrated" to include the stiction, then my readings are too low
now. A ~20% change is *not* small.

they're calibrated dry, so they should be used dry. we can all easily
point out that reducing friction is a good thing in theory, but in
reality, this is a $60 device and it's a question of how it was
calibrated. got to be consistent if you want to measure absolutes.
relatives too for that matter.

i say stay dry.

jim beam wrote:
Ron Ruff wrote:
Basically that is it. I got the idea yesterday to lube (Dupont Teflon
lube) my 4 month old Park gauge yesterday, because I figured "what
could it hurt?". A spoke that previously measured 129kg (2 days ago)
now measures 105kg. A spoke that measured 102kg now measures 80kg.
Both are without tires, in case you were wondering.

Lubrication is probably a good thing, since if there is stiction in
the device that will reduce the consistency of the readings. My
question is... which one is likely to be correct? If they are
"calibrated" to include the stiction, then my readings are too low
now. A ~20% change is *not* small.

they're calibrated dry, so they should be used dry. we can all easily
point out that reducing friction is a good thing in theory, but in
reality, this is a $60 device and it's a question of how it was
calibrated. got to be consistent if you want to measure absolutes.
relatives too for that matter.

i say stay dry.

How dry? Finger/nipple grease and lube will invariably find its way onto
the meter. Does this mean it needs to be degreased before each use?

--
Phil

It hardly seems that stiction will be so predictable and smooth that it can
be included in the calibration of a measuring instrument. Ever heard of
"slip-stick?" Once the surfaces begin to slide, they come to a new resting
place, and start to build up unreleased force again. At the other extreme
from the tensiometer we have earthquake faults.

On Mar 24, 2:04 pm, "Leo Lichtman"
wrote:
It hardly seems that stiction will be so predictable and smooth that it can
be included in the calibration of a measuring instrument.

That's what I was thinking... you'd want stiction to be out of the
picture entirely, or at least reduced to a negligible level. If I can
reduce the readings by 20% by adding a little lube, then it isn't hard
to imagine a little corrosion or dirt adding more than 20% to the
original stiction.

Does everyone elses make a scraping noise as it is opened and closed?
I thought lubrication would get rid of that but it didn't seem to
help. It is coming from the pointer which has two washers (nylon?) on
either side. Oddly, one of the washers actually rubs on the scale...
the scribed marks in the aluminum plate. That doesn't seem like a very
good design. Anyway, the scrapng sounds like metal on metal, but I
don't see any metal on metal contact.

Hang a 100Kg weight off a spoke and you can calibrate it.

"Ron Ruff" wrote in message
oups.com...
Basically that is it. I got the idea yesterday to lube (Dupont Teflon
lube) my 4 month old Park gauge yesterday, because I figured "what
could it hurt?". A spoke that previously measured 129kg (2 days ago)
now measures 105kg. A spoke that measured 102kg now measures 80kg.
Both are without tires, in case you were wondering.

Lubrication is probably a good thing, since if there is stiction in
the device that will reduce the consistency of the readings. My
question is... which one is likely to be correct? If they are
"calibrated" to include the stiction, then my readings are too low
now. A ~20% change is *not* small.

On Mar 24, 3:50 pm, "Ron Ruff" wrote:
good design. Anyway, the scrapng sounds like metal on metal, but I
don't see any metal on metal contact.

Correction... the two metal arms *are* rubbing on each other. That is
the greatest source of noise.

On Mar 24, 5:26 pm, "Ron Ruff" wrote:
On Mar 24, 3:50 pm, "Ron Ruff" wrote:

good design. Anyway, the scrapng sounds like metal on metal, but I
don't see any metal on metal contact.

Correction... the two metal arms *are* rubbing on each other. That is
the greatest source of noise.

There is no rubbing between the two metal arms on my TM-1. The only
points of contact between the black arm and the blue arm are along the
tension "scale", isolated plastic washers, and the the pivot point
itself (on the pivot pin). But no rubbing contact.

Perhaps your example is damaged in some way?