Taps – What material?

This topic has 11 replies, 10 voices, and was last updated 27 April 2012 at 14:43 by Jeff Dayman.

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26 April 2012 at 23:02 #6112
ChrisH
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@chrish
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26 April 2012 at 23:02 #89786
ChrisH
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@chrish
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
26 April 2012 at 23:33 #89788
MICHAEL WILLIAMS
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@michaelwilliams41215
Most people will say HSS is best and that's true for general purpose use and bigger taps .

Down in the world of Model Engineering and little taps and fine work though it's not so obvious and carbon steel taps work very well when used on common materials like mild steel and brass .

Edited By MICHAEL WILLIAMS on 26/04/2012 23:35:54
26 April 2012 at 23:50 #89792
Chris Trice
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@christrice43267
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.
27 April 2012 at 06:10 #89795
Bill Pudney
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@billpudney37759
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
27 April 2012 at 09:16 #89799
Douglas Johnston
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@douglasjohnston98463
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
27 April 2012 at 09:27 #89800
Terry Lane
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@terrylane
I have a preference for good quality carbon steel taps.
27 April 2012 at 09:53 #89802
Russell Eberhardt
Participant
@russelleberhardt48058
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.
27 April 2012 at 09:54 #89803
Terryd
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@terryd72465
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
27 April 2012 at 10:55 #89806
ChrisH
Participant
@chrish
Thanks to all who have replied so far. It would appear that there are supporters for both HSS and CS taps out there, perhaps the ability to buy good quality HSS taps more easily and more cheaply than CS would persuade quite a few, me included!

It would also appear that CS taps may suffer adverse comments as possibly most that are readily available are not what would be called 'good quality'; I don't know, just speculating.

Now, as it happens, I do have a broken CS tap, not of the highest quality I must add, which has broken off whilst cleaning out a M5 previously tapped hole. My fault, was clumsy and was rushing the job, always fatal.

Terry, you mentioned a heat process to degrade the tap hardness which is presumably heating the beggar up a bit for a while. Could you elaborate a bit more please? Many thanks,

Regards, Chris
27 April 2012 at 12:37 #89812
Tony Ray
Participant
@tonyray65007
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 !
27 April 2012 at 14:43 #89818
Jeff Dayman
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@jeffdayman43397
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
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