[bj_cardiff]

I've recently brought a second hand livestock scales but their not showing the right weight. The weigh scales are Salter, does anyone know how to calibrate them?

[Sbom]

We do ours with 20kg feed bags 

[bj_cardiff]

Sorry, what I meant was that when I put a 20kg weight in it reads as 28kg, so how do I adjust the scales so that it reads as 20? 

[Backinwellies]

put a second 20kg bag on ...... does it weight 48kg now?  if so just take 8kg off any weight   ....   

[pharnorth]

Should have a knob or button somewhere you can use to adjust it so it is tarred to Zero with nothing on it.  Also check the platform isn't impeded by some kind of obstruction or need a bit of oil as it maybe sticking.

[bj_cardiff]

It seems to add around 4kg to every 10kg of weight on it. It does have a adjustor so you can set the zero weight to zero (which I have done).

[mab]

It seems to add around 4kg to every 10kg of weight on it. It does have a adjustor so you can set the zero weight to zero (which I have done).

sounds like one of the springs inside the scale has broken/ fallen off (mine has four springs in parallel)- if you can get a replacement (or re-attach the original) that would be the way to go, otherwise it may be simpler to divide reading by 1.4, or (if you can get at it without breaking it) paint out the old scale and mark on new divisions using 20kg bags as sbom suggests.

[shep53]

Not sure if I understand what you are saying , you put a 20 kg bag in the middle of the scales and it reads 28kg so you turn the adjuster until it says 20 kg , when the scale is empty it doesn't  matter  that the needle is not at zero , if the adjuster is at maximum  and still not right then remove the tiny nut holding the needle , pull of the needle and  realign  pointing to zero after centralising the adjuster .  You could take the back off the scale and clean /lubricate , they are simple and  very robust my set is  40 yr old  and going strong