Weighing vehicles simply

What a great idea. A project for several of our team.

My homemade jack scale.
You will need to locate a hydraulic bottle jack that has a service port. This will be a screw out plug on the bottom of the jack. Unfortunately, jacks at Wal-Mart and Pep Boys (made in China) no longer seem to have the service port. So, you may need to search out yard sales or an older friends garage to find a bottle jack with the port. Remove the plug from this port and install a pressure gauge - I selected a liquid filled gauge that will measure up to 3,000#. To convert this to weight, measure the diameter of the jack cylinder (mine was 1.125 inches) and apply a little math to get the area of the cylinder (3.14 x radius squared). In my case 1.125 diameter /2=0.5625 radius x 0.5625 radius = 0.3164 x 3.14159 (pie) = 0.994 (my jack factor). Multiply the area by the pressure and you get weight.

The above information was originally found on an RV Camper forum and written by “Professor95”.
I changed the numbers to match my jack dimensions.
If you use a jack with a 1-1/8” cylinder you can use the direct read from the gauge and be accurate within 6 pounds per thousand. Gauge reading =1000# = 994# actual.


Gauge at Northern Tool was 12 bucks and the adapter fitting was about $6.59.
If you have a rubber plug and spring behind the service port metal screw remove the rubber and leave the spring. If the spring is so small in diameter that it slides into the new fitting you should cut a small hole in the rubber disk and use it as a spring stop. I think the spring holds pressure on a metal ball valve.

The front of my Baja weighs 706#






Dia Factor

1.125 0.994018711
1.5 1.767144375
2 3.14159
2.5 4.908734375

Lang I hope your not going to work under there with no chocs under the back wheels

Bluey

Bluey60 wrote:

Lang I hope you're not going to work under there with no chocs under the back wheels

Bluey

:roll:

kinda got the impression he was just showing us how to weigh it ... ....

Thats a great idea, could also use this idea for the hydraulic press

Paul

Mrsmackpaul wrote:

Thats a great idea, could also use this idea for the hydraulic press

Paul

Paul, I have an Old 100Ton Servex Press, & it has a Gauge mounted on it. & It's even calibrated to Tons. So I assume It's a factory Fit..


Bluey, I'm Pretty sure Lang has Just Copied & Pasted his entire post from another Forum.. BISTBC..

We had a set of jack scales back in the sixties.



LN700

Bluey I think you know I am not into VW's. I always practice safety and if a dropped nut bounced into the centre of the vehicle I would get one of the grandkids to crawl in and get it.

If I don't think I can fool all of the people some of the time I try to put stolen information in italics. I don't bother with self-explanatory things like photo captions and screen shots.

I just looked and I have both a gauge and a suitable jack. I might see if I have enough suitable fittings and report back.


Lang

Dad did something similar on a front end loader years ago, fitting a gauge into the lift hydraulics. He then picked up several different known weights to calibrate the gauge, and marked it with a texta. I think the loader arms always had to be at the same certain height off the ground when taking a reading though, to avoid false readings.

I have also seen the same idea on a semi tipper hoist. The driver put the hoist up about 3 or 4 inches while he loaded. I reckon his trailer had airbag suspension with a weight gauge, but the prime mover was on springs, and apparently the gauge plumbed into the hoist gave him a guide to avoid overloading.

180wannabe wrote:

I have also seen the same idea on a semi tipper hoist. The driver put the hoist up about 3 or 4 inches while he loaded. I reckon his trailer had airbag suspension with a weight gauge, but the prime mover was on springs, and apparently the gauge plumbed into the hoist gave him a guide to avoid overloading.

Now thats a clever idea, I can see this in my future

Paul

180wannabe wrote:

I have also seen the same idea on a semi tipper hoist. The driver put the hoist up about 3 or 4 inches while he loaded. but the prime mover was on springs, and apparently the gauge plumbed into the hoist gave him a guide to avoid overloading.

Back in the days before Airbag truck suspension. I had this setup, & with a bit of practice, I could get the Weight over the Drive to within 100kgs of Legal every Time....