On 29 Mar, 14:36, "Keith (Southend)G"
wrote:
I thought I'd see if I could re-calibrate my Davis WMII tipping bucket
raingauge this morning, as I have a feeling it is recording on the low
side.

I found this - which is prolly more than you ever wanted to know...
http://www.reed-sensor.com/pdfs/RRE_...ch_Catalog.pdf
http://www.reed-sensor.com/pdfs/RRE_...itch_Notes.pdf

Last page of the catalogue has "do's and don't's".