In article . com,
dcbwhaley wrote:
Any advice on buying taps. I need sizes from 2.5mm to 6mm (including
3.5 mm - even though my local DIY shop tells me metric screws only come
in whole numbers) for tapping mainly aluminium and occassionally mild
steel.

MY internet search seems to find huge sets of taps and dies at
suspiciously low prices or individul items at pocket wrecking prices.
Materials seem to be carbon steel, tungsten steel and high speed steel.
Which is best?

I think you've answered your own question. For serious use you need
expensive HSS types. For occasional use where the thread isn't really
critical a cheap set might be ok - although they tend to vary somewhat.
I bought a Draper set in desperation one Sunday after 'losing' a
particular one I needed and they proved ok at the price.

--
*There are 3 kinds of people: those who can count & those who can't.

Dave Plowman London SW
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