Home Made Corner Scales

[Jack Olsen]

This is a project I've got $110 in, so far. I think it's probably more accurate than the typical grassroots 'Ruggles' approach of using a single bathroom scale with a lever cradle to reduce the force on the scale by a factor of four. I just bought sixteen scales at Ikea -- at $5.99 a pop. I was able to test for accuracy by, well, standing on each one. They were all within a pound, and with this kind of redundancy, the 'noise' of the scales' inaccuracies can cancel each other out, somewhat.





My first attempt used a cut up 4x4 and only 10 scales. When the car fell off the 4x4, I decided another approach was in order.

So out came the welder and a rusty old piece of 1x1x1/8" tubing.



Testing:



Once I got all four corners level and at the same height, I got easily-repeatable results. Thinking I had a full tank, I got 2,404 pounds. Then I took the car out and learned I was 2.5 gallons under a full tank. After topping off, I got 2,421 pounds. This is within a fraction of one percent of the Hergesheimers scales. Corner weights check out pretty well, too.



Granted, it's kind of a pain in the butt. And if you didn't have a lift, it would be even more time consuming. But it seems to work.

[Bob Kontak]

How sweet is that?

BOLMEN Scale - IKEA

[Joe Bob]

I would suggest rollers.....that way you can flatten out the suspension after an adjsutment.

[Bob Kontak]

Rollers like on a dyno or at the DMV test facility?

[RWebb]

Jack - you have a serious problem.

[Alan Lindquist]

Originally Posted by RWebb

Jack - you have a serious problem.

DUH! God bless Jack!

[midnight911]

well done, Jack!
i've seen people try this and fail. but little more push and creativity like you did, i learn it is possible.

[Jack Olsen]

Originally Posted by RWebb

Jack - you have a serious problem.

I can't argue with that.

I'm glad no one was watching. After the first weighing, I realized the trunk was still packed with all of my track stuff. So I took everything out, but then -- after weighing the car again -- I decided to weigh all of the stuff I'd taken out to see if my numbers were holding up. That meant standing with a bathroom scale six or seven times in a row, each time holding some of the stuff from the trunk, checking off a list and writing down the net weight.

Kind of nuts. (But the numbers matched!)

[combatic]

Love it! Thanks for sharing Jack! ...back to grinding =)

[livi]

Brilliant!

Of course that will only work with Swedish bathroom scales.

[tazzieman]

Where do you keep all these gizmos Jack?

Good plan , well thought out.

[wayner]

Jack, we don't know each other but I have been following your adventures here for some time. I finally have to ask:

Were there any mad scientists in your family?

I love the ingenuity!

It is inspiring watching your antics :-)

[GH85Carrera]

I am lucky to have a friend that owns a set of real scales that I can borrow. He has a neat home made set of rollers. He uses large ball bearings placed into divots on a bar of steel. It takes a while to set up but it works to allow the suspension to settle.

He found the problem was when he lowered the car down the suspension does not go straight up, it is at an angle. It would tear up the scales. With the bearings and two pieces of steel on each wheel it could wiggle around as needed.

Your solution is as usual simple.

[swade]

Ikea is going to wonder about the global run on bathroom scales

[Trackrash]

Jack Olsen for president.

[chrismorse]

Hi Jack,

Being a contractor, i occasionally come across buildings and slabs that are occasionally out of plumb, level or square, so, as i was admiring your home run, (simplicity and low cost), i was considering the possibility that your floor might not be dead flat. Then, how to test for that.

On my second beer, i had a thought, just turn the car around on the scales and see if you can get real close to duplicating your prior readings.

Here is a shot of my attempts to get a flat surface to install borrowed scales and give the car a bit of room to roll back and forth to get rid of "stiction", occurring after lowering the car back on the scales after making an adjustment.

A bit heavy but fun to drive. Looking forward to getting Dad's 74 squared away.

Regards,
chris

[bfunke]

Take a look what the kart racers are using. Seems to me you could easily fab up something like this but make it a little more stout.

KART RACING PRODUCTS - SCALES & STANDS - Leather Neck Scale Fixture
Kart Scale Levelers & Racks Intercomp Racing
I've seen intercomp PT300 scales at DoD DRMO sales for around 150 a set. I think they are rated at 10K Not sure how easily they could be adapted to use as race scales.

[vash]

best thing about IKEA are the names of the products..what are those scales called?

the "Svågertorp"?

jack, is your garage floor level?

[Jack Olsen]

Originally Posted by wayner

Jack, we don't know each other but I have been following your adventures here for some time. I finally have to ask:

Were there any mad scientists in your family?

I love the ingenuity!

It is inspiring watching your antics :-)

Thanks. Both my father and my brother are engineers. I'm the crackpot in the family.

Originally Posted by GH85Carrera

I am lucky to have a friend that owns a set of real scales that I can borrow. He has a neat home made set of rollers. He uses large ball bearings placed into divots on a bar of steel. It takes a while to set up but it works to allow the suspension to settle.

He found the problem was when he lowered the car down the suspension does not go straight up, it is at an angle. It would tear up the scales. With the bearings and two pieces of steel on each wheel it could wiggle around as needed.

Your solution is as usual simple.

The wheels come down and then splay out. It moves the cradle about 3/4" over -- and then moves it 3/4" the other way when you lift it up again. So all I did was place the cradle 3/4" inboard and it settles on center. The base of the leveling feet is hard polyethylene, which glides over the scale pretty easily.

Originally Posted by chrismorse

Hi Jack,

Being a contractor, i occasionally come across buildings and slabs that are occasionally out of plumb, level or square, so, as i was admiring your home run, (simplicity and low cost), i was considering the possibility that your floor might not be dead flat. Then, how to test for that.

On my second beer, i had a thought, just turn the car around on the scales and see if you can get real close to duplicating your prior readings.

Nice ride! My floor is not flat. But the adjustable feet (and some levels) let me get all four cradles on the same plane.

[Kswelder1987]

This is awesome I run micro sprints and can't afford actual scales but need some so I might have to try this great job jack