Mechanical/Electric Scales Query

[Kaiju]

I've now weighed myself on four mechanical scales and three electric scales and I weigh one amount on the mechanical scales and another amount on the electric scales.

My question is does anyone know why the amounts are different?

 

[Kaiju]

So weird that all four mechanical scales say the same weight and the three digital scales say the same other weight. All four mechanical scales must be calibrated wrong.

 

[Kaiju]

Clever me, just used two 5kg dumbells to check both my scales and the digital scales are always accurate while the mechanical ones are only accurate if positioned a certain way.

The mechanical scales are between 0.5-1.5kg out dependant on where the weights are placed. I'll have to let my doctor know, as his mechanical scales are not fully accurate.