Taps and Dies

[Andrew TinsleyParticipant @andrewtinsley63637]

I would agree with Mick B1's comment on Rod Jenkins statement re tungsten steel taps. On the whole. I prefer good quality carbon steel taps to HSS for "shed engineering" . They always appear to be sharper than HSS. Longevity may well be worse, but I am not into serious high speed production, so who cares?

To be fair, I am talking of good quality carbon steel taps, such as supplied by Tracey Tools. I am sure that there is a good deal of rubbish carbon steel taps on the market

As an aside and tempting fate, I have never broken a carbon steel tap, but have certainly broken a fair old number of HSS taps!

Andrew.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Mick B1 on 14/07/2021 14:12:36:

Posted by Roderick Jenkins on 14/07/2021 13:41:53:

Posted by Mick B1 on 14/07/2021 12:00:52:

They are of 'tungsten steel', which I guess isn't quite HSS…

Actually, I suggest, nowhere near HSS. Normal O1 type gauge plate has 0.5% tungsten. Record plane blades were described as Tungsten Steel and they, like gauge plate, do not have the hot hardness of HSS. Most hardenable steels have various small quantities of elements such as vanadium, chromium and tungsten to modify the behaviour of the microstructure during the heating, quenching and tempering process. I suggest that in every day model engineering terms tungsten steel is no different to carbon steel.

Rod

Probably not, but in every day model engineering use at hand-driven speeds at shed temperature, not greatly different from HSS either.

Well, except HSS might be a Tungsten Steel! (Table from wikipedia.) Note T1, M2 and M35 all contain more Tungsten (W) than anything else.

I dislike over-generalising about families of steel in hope of keeping life simples. It's unsafe because, as in human families, individuals may be similar or completely different. My family tree includes an actual Saint and a chap hung for Sheep Stealing. Dead Mild Carbon Steel is completely different from the High Carbon steel used to make knives, the chemical difference being 2% carbon, which completely alters how the metal behaves.

The reason an alloy is allocated to a 'family' varies too. Carbon Steel is decided by the Chemical composition, whereas HSS covers any cutting steel that retains hardness at high temperature – the chemical composition doesn't matter much. Tool Steels may be Carbon Steels, or not.

Other elements added to Iron radically alter the alloy's properties too. Tungsten improves hardness and temperature resistance. The clue whether it matters in a cutter is in the High-speed designation. If a cutter is driven at high-speed by a machine it's going to get hot! Therefore, machine tools cut best with HSS or Carbide. Hand tools are unlikely to get hot enough destroy their hardness, so HSS isn't necessary. The right grade of Carbon Steel will often do just as well, and it's easier to sharpen and heat treat.

Chap mentioned on telly the night it's possible to date knives from what their blades are made of. No large scale professional knife maker has used plain Carbon Steel since about 1980 because stronger, harder and stainless alloys are available. Quite likely any modern blade contains Tungsten.

May I warn again about notions of 'quality'. Modern materials are formulated to meet particular specifications, which may not meet your requirement, so don't assume it's rubbish. Unsafe to assume tags like 'HSS' or 'Tungsten Steel' are more than indicators. In the worst case they are simply advertising, harking back a century or more to when alloy steels were first hitting the market.

Specification matters. Ordinary twist drills are fine for wood and easily spoilt cutting metal. HSS will do better on metal, but may be a waste of money in a wood-working shop. Tungsten Steel could be a decent compromise, but might be inferior on wood to cheap drills protected with TiN. As some woods and man-made substitutes are abrasive, might pay to minimise tool changes by standardising on tougher drills.

Home workshops tend to assume long tool life is top dog: not so professionally, where a Production Engineer carefully assesses the overall cost of tool changes and cutting rate. His logical calculation could lead him to using cheap disposable cutters or the best money can buy; which is bought depends on the overall cost, not brand-names or advertising. Quite likely HSS isn't good enough, and he'll go for carbide or something even harder like Boron Nitride.

In a home-workshop much depends on owner psychology. I'm content if my tools do what I need of them for a reasonable time. My workshop is grubby and full of inexpensive tools I consider disposable in cardboard boxes. Drives my mate mad! His motorbike focussed workshop is pristine, full of SnapOn spanners, roller bearing cabinets, and other expensive goodies. I do lots of semi-finished utilitarian work, he does a lot of polishing! As long as we don't compare notes, we're both happy!

I've given up fussing about tools, and just buy mid-range stuff from reputable UK suppliers. The country of origin doesn't matter much, which is just as well because it's difficult to tell. Equally good Dormer drills were made in England, then Italy, and then Mexico. I believe current production is in Brazil…

Dave

[John ReeseParticipant @johnreese12848]

My preference is to purchase taps and dies when needed. I select either spiral flute or spiral point depending on whether a blind hole or a through hole. I buy my taps and dies from an industrial supply house instead of a dealer who caters to the hobby trade. That gives me access to a greater range of taps and better quality taps.

[Bill PudneyParticipant @billpudney37759]

+1 for everything John Reese said!! In addition I stow a good tapping drill with the tap and die.

cheers

Bill

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