I have never seen such a thing,have you?
I have never seen such a thing,have you?
Nope
Looks homemade, but with a simple conversion could work fairly well. depends on the gradient of the gauge. Now build a set with digital gauges and it could be very accurate.
I have a set. They were mostly used by circle track guys. I don't remember the manufacturer, but they were popular with low budget racers. They worked pretty well.
I want a set now.
A year or two ago I thought about making a set with bottle jacks and pressure gauges.
Never did it yet though. I think it started getting spendy with the gauges needed.
In reply to Robbie:
Now you have me thinking. That's dangerous.
Definitely don't search how to do it on YouTube.
And I'd love to see what you come up with.
I've seen them for checking tongue weight on trailers. I played around with making one, but the diameter of the piston and the range/increments of the gauge have to match, and you have to have a way to set zero as temperature changes.
The gauge and diameter thing doesn't matter if you are willing to do a bit of math. If you know p/si and si you can get back to p.
It is true though, you could find a piston with a bore of exactly 1 in2, and then psi readout is lbs. Or maybe people make gauges set for a specific bore and the math is done for you so it reads in lbs rather than psi.
I'd think you could zero them with the jack pump, no?
Robbie wrote: The gauge and diameter thing doesn't matter if you are willing to do a bit of math. If you know p/si and si you can get back to p. It is true though, you could find a piston with a bore of exactly 1 in2, and then psi readout is lbs. Or maybe people make gauges set for a specific bore and the math is done for you so it reads in lbs rather than psi. I'd think you could zero them with the jack pump, no?
I think if you use electronic senders you can just wire them up and calibrate them however you like using known weights.
I considered building some at one point but some people said that the friction from the seals could make the reading kind of hard to get accurately. I ended up with a set of Longacre scales instead.
D2W wrote: Now build a set with digital gauges and it could be very accurate.
The gauges don't determine the accuracy. The calibration and the consistency does.
People love digital readouts, but rarely know how to calibrate instrumentation. Making it digital does not make it accurate. Just makes it easy to read.
How would those scales compensate for fluid thermal expansion/ contraction?
I used to use one of these on the Midgets.
SVreX wrote:D2W wrote: Now build a set with digital gauges and it could be very accurate.The gauges don't determine the accuracy. The calibration and the consistency does. People love digital readouts, but rarely know how to calibrate instrumentation. Making it digital does not make it accurate. Just makes it easy to read.
True but getting an accurate reading on an analog gauge is going to be hard. If you are only interested in knowing to an accuracy of +/- 50 lbs no problem. Digital gauges are readily available down to tenths.
SVreX wrote: How would those scales compensate for fluid thermal expansion/ contraction?
As long as the liquid chamber is set up like single acting cylinder with a free air chamber on top your captive fluid could expand/contract with no change in internal pressure.
They are only $50 face on book
Stampie wrote: I want a set now.
D2W wrote:SVreX wrote: How would those scales compensate for fluid thermal expansion/ contraction?As long as the liquid chamber is set up like single acting cylinder with a free air chamber on top your captive fluid could expand/contract with no change in internal pressure.
Makes sense
djsilver wrote: I've seen them for checking tongue weight on trailers. I played around with making one, but the diameter of the piston and the range/increments of the gauge have to match, and you have to have a way to set zero as temperature changes.
Why would temperature play a role? Weight pushes down on piston, pressure goes up in direct correlation with the area of the piston.
One of our lifts at work has a pressure gauge on it, I keep thinking about noting the empty-lift pressure, then putting my car (a known value) on it and noting the pressure. Should be able to get reasonably close, within a couple hundred pounds. Empty-lift weight is around 400-500psi and the heaviest trucks we work on are around 1500-1800psi so that defines the granularity. Guesstimating around 10lb per psi.
Knurled wrote: Why would temperature play a role?
Because fluid expands.
SVreX wrote:Knurled wrote: Why would temperature play a role?Because fluid expands.
It'll still be 0psi with no load on it, X/area PSI with load on it. Temperature irrelevant.
In reply to Knurled:
OK, so explain...
Assume 0psi with no load. Extreme temperature, fluid expands. What happens to psi?
If the fluid has no where to go, doesn't psi increase?
Seems to me there would need to be some kind of expansion chamber for the psi to remain 0.
And since temperature change would affect all four the same it would cancel out anyway. On a hot summer day they would just be a little further off the floor than in the middle of winter.
Which brings up the real issue: Empty height. If there is a tiny bit more fluid or something in one stand so that they aren't exactly the same height empty that tall one would act like it was weight jacked and read a higher pressure/weight.
oldopelguy wrote: And since temperature change would affect all four the same it would cancel out anyway. On a hot summer day they would just be a little further off the floor than in the middle of winter.
Thank you.
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