Scales (in Britain)
1) Is the word 'scales' (instrument used to weigh people or things, plural in Britain with this meaning) used with plural verbs when it means 'one single instrument'? ('the scales is' or 'the scales are'?).
2) How can I indicate one single intrument with 'determiners'? 'A scales' or 'one scales' seems odd, but if it were 'some scales', there may be confusion with the plural (more than one single instrument). The same problem with this/these, etc.