Taps

One thing I can tell you from experience is that small taps in HSS when broken into a part make a sound two octaves up on the expensive scale. More of a *ping* Carbon had more of a flattish *crunch* to it.

-- Regards,

John Stevenson Nottingham, England.

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You're asking the wrong question. What's of benefit, in any workshop situation, is a high quality tap made to an exact size and ideal geometry that will cleanly cut correctly sized threads and not break in the middle of the job. Cheap tap and die sets made in Itchifanni won't do any of the above and are invariably made of carbon steel. High quality taps made by reputable manufacturers are invariably made of HSS. It's not primarily the material though, it's the manufacturing quality you should be looking for.

Most of my taps are second hand and come from Sert Tools in Farnham Common near Slough. I go for a rake through the tap, die, reamer and milling cutter bins every now and then for a couple of hours and pay about 50p to a quid per item. I look for quality names, Presto, Dormer, T&J etc and invariably come away with a bag full of 'as new' items for the price of a drink. I'd rather have a good second hand tap than a new crappy one. It's also a nice way to spend an afternoon in their Aladdin's Cave.

All my shiny new toys then immediately go rusty in my SOB of a workshop despite coatings of oil and a dehumidifier but that's another story.

-- Dave Baker

HSS lasts longer, has more strength but possibly is more fragile.

I'd always go for HSS given the choice.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Thanks for the responses. I couldn't understand how you get the benefit of High Speed Steel when tapping by hand, sounds like you can't get quality taps in carbon steel so the question was a bit irrelevant really.

Thanks

Steve

You used to be able to ONLY get Carbon Steel in the earlier years of the last century, but HSS came in before WWII I believe and was in common use after the war. A lot of surplus stuff came on the market which was very good quality Carbon Steel and as long as you didn't abuse it, it gave good life.

HSS takes more work to make, has to be ground rather than other processes and snaps rather than gives like Carbon Steel does.

It's the retention of a sharp cutting edge that gives the HSS taps the better performance, and on a cost basis HSS taps would probably give 4 to 5 times the output on a machined parts basis than Carbon before sharpening.

Higher production speed possibilities made HSS the choice for anything remotely volume-orientated.

One of the reasons it is reappearing now is the third-world cheapo producers who can knock them out with too much in the way of special machines.

Peter

-- Peter A Forbes Prepair Ltd, Luton, UK snipped-for-privacy@easynet.co.uk