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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
Posted to rec.crafts.metalworking
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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 |
#2
Posted to rec.crafts.metalworking
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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. |
#3
Posted to rec.crafts.metalworking
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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. |
#4
Posted to rec.crafts.metalworking
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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 |
#5
Posted to rec.crafts.metalworking
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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 |
#6
Posted to rec.crafts.metalworking
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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? |
#7
Posted to rec.crafts.metalworking
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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 |
#8
Posted to rec.crafts.metalworking
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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. |
#9
Posted to rec.crafts.metalworking
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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 |
#10
Posted to rec.crafts.metalworking
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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 |
#11
Posted to rec.crafts.metalworking
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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 |
#12
Posted to rec.crafts.metalworking
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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 |
#13
Posted to rec.crafts.metalworking
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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 |
#14
Posted to rec.crafts.metalworking
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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 |
#15
Posted to rec.crafts.metalworking
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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 |
#16
Posted to rec.crafts.metalworking
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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 |
#17
Posted to rec.crafts.metalworking
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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 |
#18
Posted to rec.crafts.metalworking
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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 |
#19
Posted to rec.crafts.metalworking
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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 |
#20
Posted to rec.crafts.metalworking
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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 |
#21
Posted to rec.crafts.metalworking
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Made a "Forklift Scale" for the working poor
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#22
Posted to rec.crafts.metalworking
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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 |
#24
Posted to rec.crafts.metalworking
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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. |
#25
Posted to rec.crafts.metalworking
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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 |
#26
Posted to rec.crafts.metalworking
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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 |
#27
Posted to rec.crafts.metalworking
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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 |
#28
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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". |
#29
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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 |
#30
Posted to rec.crafts.metalworking
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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 |
#31
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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 |
#32
Posted to rec.crafts.metalworking
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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 |
#33
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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. |
#34
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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 |
#35
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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 |
#36
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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 |
#37
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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... |
#38
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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 |
#39
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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. |
#40
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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 |
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