Taps - What material?

This will undoubtably be mentioned elsewhere, but I can't find it, regarding material taps are made from.

Some seem to be from carbon steel, some from HSS, some from some other steel - but what are the relative merits of each and which should be considered the best?

Thanks in anticipation,

Chris

There'll be a few telling you that carbon taps can keep their edge longer than HSS because they're harder (which is true) but based purely on using both types, I'd recommend HSS because even with the greatest care, you're more likely to break a carbon steel tap than a HSS one and we all know how time consuming and often destructive removing a broken tap can be to the workpiece. IMHO, pay the extra and go for good quality branded HSS. If you really want to get into it, there are many different alloys of HSS and even carbide for particular metals but for 99% of model engineering time, regular HSS is fine.

I agree that HSS is better. Also look for "ground thread" taps. Most "name" manufacturers grind taps

In my experience all carbon steel taps have gashed flutes which leave burrs on the threaded portion. How a reasonably accurate thread can then be generated is a mystery to me.

Also for what its worth, I would suggest that buying a set of taps be avoided. Better to buy good quality taps as and when you need them.

Finally avoid second hand taps, unless they are clearly unused.

cheers

Bill Pudney

As a general user of taps I have invariably found the HSS ones to be of better quality and cut better. I am sure there are good quality carbon steel taps out there which perform very well, but I don't seem to see them.

I think the biggest problem people have is slavishly following recommended tapping drill sizes, which often results in excessive force being needed to drive the tap and can lead to breakage. Life is so much easier when one learns to use slightly larger tapping drills when strength is not an issue.

Doug

I have a preference for good quality carbon steel taps.

IMHO what is more important than HSS vs. carbon steel is to use a good lubricant such as Rocol RTD compound. I've used this with taps down to 12 BA without breaking any. Also, particularly for small taps use a stand or jig to keep the tap at right angles to the surface.

Russell.

I agree with Tel, there are good as well as poor quality CS, the same applies equally to HSS. I have produced some very good work with CS and will continue to do so.

With regard to Chris and breakage of taps, of course it is just as possible to break CS taps as it is HSS ones. However the hardness of CS taps can be often be degraded by heat processing if the part allows for such treatment as an aid to removal which is very difficult if not impossible using hobby facilities with HSS.

Regards

Terry

In my experience a used tap from a quality manufacturer does a better job than an unbranded new one.

For tapping & die-ing recommend Trefolex cutting compound, not cheap at around £13 a tin but 500ml will see out most of us - and you could always share it with your mates !

I have had good luck with Clarkson Osborne Blue Wizard HSS taps. No connection except as a satisfied customer.

Cheaper taps are no bargain. Carbon steel taps from reputable makers are OK, but there is huge variation in quality among CS taps from various makers/suppliers so I don't buy em anymore.

No matter what tap you use, it must be dead sharp. Dull taps need higher forces to cut, naturally, and that is where the trouble starts. As soon as a tap starts needing higher force to cut, sharpen it or set it aside for making other tools from its steel. Broken/dull ones make great boring bar or flycutter tools.

JD