Which tap

[Eric CoxParticipant @ericcox50497]

Which tap gives better performance. Carbon steel or HSS

[Eric CoxParticipant @ericcox50497]

[Brian HParticipant @brianh50089]

I would say HSS but for occasional use carbon steel is fine especially if the tap is ground.

Brian

[SillyOldDufferModerator @sillyoldduffer]

I've read Carbon steel takes a sharper edge and is a tad harder than HSS, but less tough. In theory Carbon steel should be fine for hand taps, but the steel is rather brittle and likely to snap if the tap goes in off-centre or is bent by the operator. Bottom line HSS takes more abuse!

With care carbon taps and dies are OK, and may be better for Brass when new. The extra toughness of HSS is good news, but it's main advantage is it stays hard up to 500 or 600°C for machine cutting, unlike Carbon Steel which softens at about 150°C

Most of the cheap carbon steel taps and dies I bought in the 70s are still fine – their inferiority shows up only after a fair amount of use. The small much used sizes have all been replaced!

[GeorgineerParticipant @georgineer]

My brother used both types in his model-making business and concluded that carbon steel holds its edge better. He routinely used carbon steel taps down to 10 BA .

George B.

[Andrew TinsleyParticipant @andrewtinsley63637]

My vote is for good quality carbon steel taps. They cut better than HSS . Having said that they loose their edge quicker than HSS.

Carbon steel taps of good quality are cheaper than HSS. So unless you use the taps day in day out, the carbon steel ones are a better bet.

Andrew.

[Anonymous]

The few carbon steel taps I have bought are for ME threads and are only used on copper alloys. I do a lot of machine tapping on the repetition lathe and the vertical mills. Consequently I tend to buy machine taps (mostly spiral flute) in preference to the traditional sets of three hand taps. If I do buy hand taps I only buy taper, and bottom in case of blind holes. Of course machine taps can be used perfectly well by hand and are often easier to use as they have better swarf clearance.

The original question is unanswerable as no context is given. So it's impossible to say X is better than Y, without even considering Z.

Andrew

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