Made a "Forklift Scale" for the working poor
 

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Made a "Forklift Scale" for the working poor
 

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

Made a "Forklift Scale" for the working poor
 

"Pete C." wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

A shutoff valve for the gauge is also a good idea so you can shut it off
if you're doing rough work that will generate a lot of pressure spikes,
and also if the gauge fails you can easily shut off the line and replace
the gauge.

Made a "Forklift Scale" for the working poor
 

Ignoramus32392 fired this volley in
:

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

Ig, since the math is simple (and you, especially, know that), I'd
suggest that instead of making up a table for your work-a-day weighing,
you do it only once to determine if there are any non-linearities (in the
gauge... the cylinder will be linear), then make a replacement SCALE for
the gauge itself.

If you don't want to disassemble the gauge, you can just make it from
transparent label stock, and stick it on the glass.

LLoyd

Made a "Forklift Scale" for the working poor
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

then make a replacement SCALE for
the gauge itself.


Hmmm... servers must've delayed messages. I see that Pete C suggested
the same thing.

He's right about the snubber and cut-off, too.

Lloyd

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, Pete C. wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

OK, the "new scale" is a good idea. The pressure snubber is something
that I never heard about. I would think that the forklift hydraulics
is somehow protected from pressure spikes, anyway?

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley in
. 3.70:

then make a replacement SCALE for
the gauge itself.


Hmmm... servers must've delayed messages. I see that Pete C suggested
the same thing.

He's right about the snubber and cut-off, too.

Lloyd

Yep, I will do that indeed.

i

Made a "Forklift Scale" for the working poor
 

On Sun, 07 Apr 2013 11:12:07 -0500, Ignoramus32392
wrote:

On 2013-04-07, Pete C. wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

OK, the "new scale" is a good idea. The pressure snubber is something
that I never heard about. I would think that the forklift hydraulics
is somehow protected from pressure spikes, anyway?

I've done something similar. My gauge was oil filled and on the end of
about 8' of flex hose, no snubber. Gauge did bounce a little but was
fine for years.

Made a "Forklift Scale" for the working poor
 

On Apr 7, 10:06*am, Ignoramus32392 ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.


Dan

Made a "Forklift Scale" for the working poor
 

On Sun, 7 Apr 2013 11:04:41 -0700 (PDT), "
wrote:

On Apr 7, 10:06*am, Ignoramus32392 ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

We low-buck racers used a bathroom scale and a 2 x 8 with a fulcrum. A
mess to set up, but it worked.

And I made my own tire-temperature gauge with a 1N914 diode for a
sensor and an op-amp and analog gauge. Accurate to within a degree or
so, and dirt cheap.

1N914s, unlike thermistors, are linear as hell and they respond in
about one second to tire temperatures. Leads must be short, however.

--
Ed Huntress



Dan

Made a "Forklift Scale" for the working poor
 

On Apr 7, 1:23*pm, Ed Huntress wrote:
On Sun, 7 Apr 2013 11:04:41 -0700 (PDT), "





wrote:
On Apr 7, 10:06*am, Ignoramus32392 ignoramus32...@NOSPAM.
32392.invalid wrote:

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. *I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. *And I have always wondered how accurate that
approach was. *Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. *There
of course one does not need absolute weight.

We low-buck racers used a bathroom scale and a 2 x 8 with a fulcrum. A
mess to set up, but it worked.

And I made my own tire-temperature gauge with a 1N914 diode for a
sensor and an op-amp and analog gauge. Accurate to within a degree or
so, and dirt cheap.

1N914s, unlike thermistors, are linear as hell and they respond in
about one second to tire temperatures. Leads must be short, however.

--
Ed Huntress





Dan- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Good ideas Ed...I especially like homegrown solutions.

TMT

Made a "Forklift Scale" for the working poor
 

On Apr 7, 10:57*am, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this volley 8.3.70:

then make a replacement SCALE for
the gauge itself.

Hmmm... servers must've delayed messages. *I see that Pete C suggested
the same thing.

He's right about the snubber and cut-off, too.

Lloyd

Agreed...

TMT

Made a "Forklift Scale" for the working poor
 

On Apr 7, 11:12*am, Ignoramus32392 ignoramus32...@NOSPAM.
32392.invalid wrote:
On 2013-04-07, Pete C. wrote:







Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

OK, the "new scale" is a good idea. The pressure snubber is something
that I never heard about. I would think that the forklift hydraulics
is somehow protected from pressure spikes, anyway?- Hide quoted text -

- Show quoted text -

But the guage isn't...it will have a limit beyond it goes...

TMT

Made a "Forklift Scale" for the working poor
 

On Apr 7, 12:04*pm, whoyakidding's ghost
wrote:
On Sun, 07 Apr 2013 11:12:07 -0500, Ignoramus32392





wrote:
On 2013-04-07, Pete C. wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

OK, the "new scale" is a good idea. The pressure snubber is something
that I never heard about. I would think that the forklift hydraulics
is somehow protected from pressure spikes, anyway?

I've done something similar. My gauge was oil filled and on the end of
about 8' of flex hose, no snubber. Gauge did bounce a little but was
fine for years.- Hide quoted text -

- Show quoted text -

The oil filled is for vibration.

TMT

Made a "Forklift Scale" for the working poor
 

On Apr 7, 2:23*pm, Ed Huntress wrote:


We low-buck racers used a bathroom scale and a 2 x 8 with a fulcrum. A
mess to set up, but it worked.


--
Ed Huntress


It is not a lot of money to make a cylinder out of aluminum, make a
piston using an O ring for the seal ,and connect it to a pressure
gage. I think we made a set of four and spent less than $10 per
wheel, not counting engineering and manufacturing time. It was worth
while for circle track racing where you were adjusting the suspension
often. Might not be worthwhile for sports cars.

Dan

Made a "Forklift Scale" for the working poor
 

whoyakidding's ghost fired this volley in
:

My gauge was oil filled and on the end of
about 8' of flex hose, no snubber. Gauge did bounce a little but was
fine for years.


Hoses expand and contract more than one might assume, based on their
pressure ratings. The hose (that long) WAS the 'snubber'. Essentially,
the same as adding a small air accumulator near the gauge, but using the
flexibility of the hose instead of the compressiblity of air to do the
absorbing of the spikes.


Lloyd

Made a "Forklift Scale" for the working poor
 

Too_Many_Tools fired this volley in
:

Good ideas Ed...I especially like homegrown solutions.

I did essentially the same thing in reverse when we needed a 0.01g
balance at work ASAP, and the one we ordered was a week away.

I built a small lever/fulcrum arrangement from K&S brass stock and sewing
needles that multiplied the force by 10X.

Of course, we were working with a total load of only 2g G.

LLoyd

Made a "Forklift Scale" for the working poor
 

" fired this volley in news:a5aaeefa-
:

It is not a lot of money to make a cylinder out of aluminum, make a
piston using an O ring for the seal ,and connect it to a pressure
gage.

It's cheaper in mistakes and time to buy PortaPower shorty cylinders, and
convert them to purpose. They're rated at 10Kpsi.

LLoyd

Made a "Forklift Scale" for the working poor
 

On Apr 7, 3:17*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:


It's cheaper in mistakes and time to buy PortaPower shorty cylinders, and
convert them to purpose. *They're rated at 10Kpsi.

LLoyd

But not as much satisfaction in having made something. The 10kpsi
would have been wasted. The car weight was about 2000 lbs and only
about 500 psi per wheel.


Dan

Made a "Forklift Scale" for the working poor
 

"Ignoramus32392" wrote in
message ...
On 2013-04-07, Lloyd E. Sponenburgh lloydspinsidemindspring.com
wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this
volley in
. 3.70:

then make a replacement SCALE for
the gauge itself.


Hmmm... servers must've delayed messages. I see that Pete C
suggested
the same thing.

He's right about the snubber and cut-off, too.

Lloyd

Yep, I will do that indeed.

i

You might check if the indicated weight varies going up or down, or
close in vs out at the tips, from friction.
jsw

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392 ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

I will try to play with it and see.

I have a 5k forkilft that weighs about 8k lbs. I want to see if the
position on forks matters, etc, and how to get the most reproducible
pressure (creeping up vs stopped vs creeping down).

Extreme accuracy does not matter, +/-3% would be fine.
i

Made a "Forklift Scale" for the working poor
 

On 4/7/2013 8:10 AM, Pete C. wrote:

"Pete C." wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

A shutoff valve for the gauge is also a good idea so you can shut it off
if you're doing rough work that will generate a lot of pressure spikes,
and also if the gauge fails you can easily shut off the line and replace
the gauge.
I agree with Pete on the shut off. Use a needle valve. Also, if the
gauge is oil-filled, the shocks won't damage it. there was an oil filled
gauge on the main cylinder of a hydraulic plastic injection molding
machine I used to have. Believe me, there was lots of shock there!

Paul

Made a "Forklift Scale" for the working poor
 

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

I will try to play with it and see.

I have a 5k forkilft that weighs about 8k lbs. I want to see if the
position on forks matters, etc, and how to get the most reproducible
pressure (creeping up vs stopped vs creeping down).

Extreme accuracy does not matter, +/-3% would be fine.
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul

Made a "Forklift Scale" for the working poor
 

Paul Drahn wrote:

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

I will try to play with it and see.

I have a 5k forkilft that weighs about 8k lbs. I want to see if the
position on forks matters, etc, and how to get the most reproducible
pressure (creeping up vs stopped vs creeping down).

Extreme accuracy does not matter, +/-3% would be fine.
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul

When printing a new scale for the gauge it should be easy enough to
include different color scales for each mast stage and the weights
corrected for that stage. Little different than gauges with PSI and KPa
scales, in fact I believe the gauges Enerpack uses on their presses have
scales for PSI, and several scales indicating tonnage for different
cylinders they make.

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, Jim Wilkins wrote:
"Ignoramus32392" wrote in
message ...
On 2013-04-07, Lloyd E. Sponenburgh lloydspinsidemindspring.com
wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com fired this
volley in
. 3.70:

then make a replacement SCALE for
the gauge itself.


Hmmm... servers must've delayed messages. I see that Pete C
suggested
the same thing.

He's right about the snubber and cut-off, too.

Lloyd

Yep, I will do that indeed.

i

You might check if the indicated weight varies going up or down, or
close in vs out at the tips, from friction.

Yes, it does, I just checked. It varies by 20 PSI. Not that big of a
deal, and it is very consistent.

i

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, Paul Drahn wrote:
On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

I will try to play with it and see.

I have a 5k forkilft that weighs about 8k lbs. I want to see if the
position on forks matters, etc, and how to get the most reproducible
pressure (creeping up vs stopped vs creeping down).

Extreme accuracy does not matter, +/-3% would be fine.
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul

Mine is like that, also. Just a little bit more work to make a
conversion table.

i

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, Paul Drahn wrote:
On 4/7/2013 8:10 AM, Pete C. wrote:

"Pete C." wrote:

Ignoramus32392 wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

Print up a new scale for the pressure gauge so the weight can be seen at
a quick glance rather than referring to a chart. Also make sure you put
a pressure snubber orifice in the feed to the gauge to help protect it
from pressure spikes.

A shutoff valve for the gauge is also a good idea so you can shut it off
if you're doing rough work that will generate a lot of pressure spikes,
and also if the gauge fails you can easily shut off the line and replace
the gauge.
I agree with Pete on the shut off. Use a needle valve. Also, if the
gauge is oil-filled, the shocks won't damage it. there was an oil filled
gauge on the main cylinder of a hydraulic plastic injection molding
machine I used to have. Believe me, there was lots of shock there!

The gauge is NOT oil filled.

i

Made a "Forklift Scale" for the working poor
 

OK, I changed the non-liquid-filled 3,000 PSI valve, for a liquid
filled, stainless 5,000 PSI valve. I think that it will "do it".

Made a "Forklift Scale" for the working poor
 

"Paul Drahn" wrote in message
...
On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:



So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i

I would be interested is knowing how linear the weight / pressure is.
Where I worked they have a sling test tower where they proofed and
certified weight handling gear. I am pretty sure they ignored any
possible non linear effects and just multiplied the pressure by the
area of the piston. And I have always wondered how accurate that
approach was. Have also been involved with making small weight scales
to go under each wheel of a race car to set up the suspension. There
of course one does not need absolute weight.

I will try to play with it and see.

I have a 5k forkilft that weighs about 8k lbs. I want to see if the
position on forks matters, etc, and how to get the most reproducible
pressure (creeping up vs stopped vs creeping down).

Extreme accuracy does not matter, +/-3% would be fine.
i
My forklift is a double section unit. I know there is a name for that, but
don't remember it. Once the fork carriage gets to the top of it's track, a
second section begins to go up. If you machine is like that, your weight
will only be correct when using the lower section.


Actually, pretty sure most telescopic forklift cylnders are of the constant
thrust/ constant speed variety; with each piston section having the same
surface area.

If they were not, the mast lift speed would abruptly change as each cylinder
section arrived at the end of it's respective stroke making it fairly
difficult to accomplish a controlled lift.

https://www.youtube.com/watch?v=T-rJndNbCYY

Made a "Forklift Scale" for the working poor
 

On 2013-04-07, jeff wrote:
On Sun, 07 Apr 2013 09:06:41 -0500, Ignoramus32392
wrote:

Ever since I decided to get more into scrap metal, I always wanted to
add a weight scale to my 15k forklift, so that I would instantly know
how much am I lifting.

That way I could learn estimating a lot quicker, and also avoid those
overweight truck fines. We almost got his with one, with cops weighing
the rear axles at 33,100 lbs, so close to the 34,000 lbs limit.

The problem was that the scales are expensive, starting from $730 and
up. And all they do is measure the cylinder pressure and convert that
into lbs, according to a linear formula.

So, instead, I took advantage of an opportunity, since the main
cylinder hose on my forklift was leaking a bit and needed to be
replaced. I took a "precision temperature compensated 3,000 PSI
pressure gague", that I had laying around. When replacing the main
hose, I added a tee and hooked up the scale into that.

So, now I always know the main cylinder pressure. I am going to weigh
a few things of known weight (I do have a 10k floor scale, so it not
hard to come up with known weights). Then I would write up a table of
weight/pressure values and run a linear regression, then I would print
out a table with these values. That way we'll know for sure what
weighs how much.

I did hook all of that up yesterday, but did not yet play with this
due to lack of time, but I plan on doing so shortly.

i
That may work for you but be very careful if it needs to be very
accurate,

It does not need to be very accurate. Plus or minus 200 lbs, or 3%,
whichever is greater, is fine.

Forklift manufactures don't do it because of liability worries of a
forklift tipping over. You need to know your weight before it goes
on the forks.

OK, you got me. If I do scrap metal, how exactly do I know the weight
before it goes on the forks?

The scale is the way to find out the weight.


i

Made a "Forklift Scale" for the working poor
 

On Sun, 07 Apr 2013 13:11:38 -0700, Paul Drahn
wrote:

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:
BIG SNIP
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..

Brian Lawson

Made a "Forklift Scale" for the working poor
 

Brian Lawson fired this volley in
:

My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..


That's not the case with all lifts, even those with double and triple-
section masts.

If the cylinder is not the telescoping variety, and if (as is often the
case), the cylinder is lifting one or a pair of sprockets that lift
chains that lift the mast (for obtaining multiplication of travel), then
the cylinder is picking up the same weight from one end of travel to the
other.

Only if the mechanical advantage or effective cylinder size changes does
the pressure vs. travel change.

The telescoping of the mast itself is just to make it all fit in a more
compact space when lowered (so it can go through doors).

LLoyd

Made a "Forklift Scale" for the working poor
 

"Lloyd E. Sponenburgh" wrote:

Only if the mechanical advantage or effective cylinder size changes does
the pressure vs. travel change.

The weight of each section of mast is added to the lift as each section
comes into play and is no longer resting on the stops.

Made a "Forklift Scale" for the working poor
 

On 2013-04-08, Brian Lawson wrote:
On Sun, 07 Apr 2013 13:11:38 -0700, Paul Drahn
wrote:

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:
BIG SNIP
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..

Brian Lawson

Brian, it is actually both, as sometimes we need to lift something
from the top with a chain, it happens often. I will just have two
tables (or one table in two columns).

i

Made a "Forklift Scale" for the working poor
 

On 2013-04-08, Lloyd E. Sponenburgh lloydspinsidemindspring.com wrote:
Brian Lawson fired this volley in
:

My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..


That's not the case with all lifts, even those with double and triple-
section masts.

If the cylinder is not the telescoping variety, and if (as is often the
case), the cylinder is lifting one or a pair of sprockets that lift
chains that lift the mast (for obtaining multiplication of travel), then
the cylinder is picking up the same weight from one end of travel to the
other.

Only if the mechanical advantage or effective cylinder size changes does
the pressure vs. travel change.

The telescoping of the mast itself is just to make it all fit in a more
compact space when lowered (so it can go through doors).

My mast has three cylinders. One in the middle, and two on
sides. Those two start extending only after the main cylinder has
extended, and at that point the pressure rises something like 1.5
times.

i

Made a "Forklift Scale" for the working poor
 

On 4/7/2013 11:17 PM, Brian Lawson wrote:
On Sun, 07 Apr 2013 13:11:38 -0700, Paul Drahn
wrote:

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:
BIG SNIP
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..

Brian Lawson
I also pick up loads from the second level of the rack system. And I
have added to the pallet box-by-box, over time, from a step ladder. I
would not know how much it weighs until the fork lift picks up the pallet.

Paul

Made a "Forklift Scale" for the working poor
 

Ignoramus24728 wrote:

On 2013-04-08, Brian Lawson wrote:
On Sun, 07 Apr 2013 13:11:38 -0700, Paul Drahn
wrote:

On 4/7/2013 12:49 PM, Ignoramus32392 wrote:
On 2013-04-07, wrote:
On Apr 7, 10:06?am, Ignoramus32392ignoramus32...@NOSPAM.
32392.invalid wrote:
BIG SNIP
i
My forklift is a double section unit. I know there is a name for that,
but don't remember it. Once the fork carriage gets to the top of it's
track, a second section begins to go up. If you machine is like that,
your weight will only be correct when using the lower section.

Paul


Hey Paul,

Yeah, but for "weighing" purposes, it will only be when "picking" the
load and not when the mast is reaching extension..

Brian Lawson

Brian, it is actually both, as sometimes we need to lift something
from the top with a chain, it happens often. I will just have two
tables (or one table in two columns).

i

Now you need to replace the gauge with a pressure sensor, some encoders
to monitor mast height and a microcontroller that will display the load
weight, lift height and mast clearance height along with programmable
alarms so you can set the doorway/ceiling headroom and get alarms when
you are about to hit the ceiling with the mast while you are busy
watching the load...

Made a "Forklift Scale" for the working poor
 

"Pete C." fired this volley in news:5162b879$0$6388
:

The weight of each section of mast is added to the lift as each section
comes into play and is no longer resting on the stops.

No doubt, but trivial compared to the sort of weights one would be
concerned about. It's not a 'non-linearity', but a step function. (If
you're on mast section 2, add 410lb, etc...

Lloyd

Made a "Forklift Scale" for the working poor
 

"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:5162b879$0$6388
:

The weight of each section of mast is added to the lift as each section
comes into play and is no longer resting on the stops.

No doubt, but trivial compared to the sort of weights one would be
concerned about. It's not a 'non-linearity', but a step function. (If
you're on mast section 2, add 410lb, etc...

Lloyd

Not so trivial if it leads you to leave 1,000# of stuff for another trip
when you could have finished the job and loaded the semi to rated
capacity if you had accurate weights. That extra trip could cost
hundreds of dollars in time and fuel, cutting into your profits. Iggy
also needs to make a trailer load calc application for a laptop or
tablet so he can enter the weight and load position on the trailer and
see the calculated axle weights.

Made a "Forklift Scale" for the working poor
 

I spent some more time on it today. I consider it to be finished.

1. The pressure gauge is now mounted nicely and firmly in a place that
is unlikely to be affected by load, chains and other forklift use.

2. I figured out how to deal with errors caused by friction. It is
very simple. I just need to take two readings, one after creeping the
load up, and the other after creeping the load down. The average
cancels friction out. Problem solved.

4. I lifted another forklift on the forks of this forklift, took down
pressures, and I now have a nice and easy conversion table, PSI to lbs.

5. I realized that maximum pressure in the system is always well under
2,000 PSI (20,000 PSI would occur only if this 15k forklift tried to
lift a 20k load). So, my oil filled 5,000 PSI gauge would have a great
cushion against pressure spikes.

6. Everything is neat and tidy, the pressure lines do not rub against
anything, the gauge is easily visible, yet protected, etc.

I will probably put similar gauges on all my forklifts.

i