Subject: highspeed steel vs.carbon steel

From: Your_Email_Address (Your_Login)
Date: 8 Jun 1996 21:16:39 GMT

Is there an advantage in using high speed steel taps for hand tapping 
instead of carbon steel? Are there any other advantages in using hss 
other than its ability to tolerate moree heat than carbon steel?

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From: [email-masked] (Russ Kepler)
Date: Sun, 9 Jun 1996 12:32:22 GMT

>other than its ability to tolerate moree heat than carbon steel?

A HSS tap will outlast a carbon steel tap above 8-1 in abrasive
materials such as cast iron and high silicon aluminum.  For some small
classes of tapping you can expect about the same life, but for a small
shop operator the advantages of HSS over carbon steel are pretty clear.

-- 
Russ Kepler posting from home  [email-masked]

                      Please don't feed the Engineers

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From: [email-masked] (ErnieLeim)
Date: 9 Jun 1996 14:04:59 -0400

High speed Taps vs. carbon steel taps ?

Carbon steel taps are more likely to shatter in the hole and will tend to
dull faster. 

Best of luck

@}---------------------------------------------------{@
                    Ernie Leimkuhler                                      

                  Stagesmith Productions                                  
                                          
                 Custom Metal Fabrication                                 
               
*    ABANA   SCA     AWS    USITT   IATSE local 15, 488   *
                        Renton, WA                                        
   
*    "Death is like being on holiday with
          a group of germans" ---- Rimmer ( Red Dwarf )
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From: [email-masked] (Peter Drumm)
Date: 10 Jun 1996 00:26:31 GMT

In message <[email-masked]> - Your_Email_Address
(Your_Login)8 Jun 1996 21:16:39 GMT writes:
:->
:->Is there an advantage in using high speed steel taps for hand tapping 
:->instead of carbon steel? Are there any other advantages in using hss 
:->other than its ability to tolerate moree heat than carbon steel?
:->

HSS taps will stay sharp a -lot- longer than carbon, and IME, don't
break nearly as easily.

[email-masked]
Using Warp/Neologic News/PMMail/iLink2/WebEx
Wausau, WI. 44d 58m 00s N x 89d 36m 45s W
All opinions are my own, even if they are wrong!

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From: [email-masked] (Clhuprich)
Date: 11 Jun 1996 13:42:02 -0400

Carbon steel has one problem -- it rusts. Sharp edges of course are
most prone to rust & corrosion. Taps that hence become dull develop
higher cutting forces, break, and/or produce a bad thread. There is also
a possible chemical reaction between the material being tapped and
the tool which is less with HSS.

Cliff Huprich

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From: [email-masked] (Bill Wyant)
Date: Tue, 11 Jun 1996 04:48:41 GMT

>other than its ability to tolerate moree heat than carbon steel?

Yes.
The high speed steel taps last much longer than regular carbon steel
taps. They will cut a more consistent hole than carbon steel taps as
they don't lose material as readily during use.

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From: Steve Wellcome <[email-masked]>
Date: 11 Jun 1996 15:34:28 GMT

>other than its ability to tolerate moree heat than carbon steel?

Not particularly.  Carbon steel is just as hard, or harder, than HSS.
Carbon steel taps have one distinct advantage over HSS; if you break
one off, you can heat it up (assuming what you broke it off in can
stand to be heated up), anneal it, and drill it out, which you can't
do with a HSS tap.

Some types of HSS may be more abrasion-resistant than carbon steel, so
the taps may last a bit longer.  But, basically, for home shop use I
don't know of any compelling reason to use HSS taps over carbon steel
taps, given equivalent quality in manufacture.  These days it may be
easier to get high-quality HSS taps, just because industry tends to
favor them for production work, but if you can get high-quality carbon
steel taps I think they'd serve just as well for hand tapping.

There's a really good book about tool steel selection, published by
Carpenter Steel Co.  It is, of course, heavily weighted toward the
proper selection of Carpenter tool steels :-) but the brand really doesn't
matter. It goes through and lists properties of various types of tool
steels, including plain water-hardening carbon steel.  In summary, 
there's no reason to use anything other than carbon steel (as made by 
Carpenter Steel Co, of course!) unless you need the particular properties 
of another steel, like resistance to heat, or resistance to warping, or 
superior abrasion resistance, or whatever.  Plain carbon steel is 
actually pretty good.

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From: Steve Wellcome <[email-masked]>
Date: 11 Jun 1996 15:34:42 GMT

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From: Charlie Greenman <[email-masked]>
Date: 12 Jun 1996 12:14:56 GMT

I think there might well be two questions being asked
here, rather than the one.

1) Is "carbon steel" (whatever the hell that is. I mean
   there are entire (and fairly large) books with
   desriptions of different "carbon steels". In fact
   of course, high speed steel is carbon steel. It is
   a particular carbon steel but most importantly a carbon
   steel with a particular heat treatment. And there are a       
   number of different HSS.) or HSS better for taps?

2) Are the taps that I am likely to find that are made out
   of "carbon steel" (see above) better or worse than the
   taps made of HSS?

I would submit, and every book I've seen on the subject
agrees (and that's why I would submit) that if you are tapping
holes by hand (nonproduction) than the correct "carbon steel"
is better than HSS for taps or dies. It's tougher, stronger,
and harder than HSS, if it is the CORRECT "carbon steel",
so long as you don't get any part of it up over about what,
400F? So, the answer to question 1 is, "Carbon steel is
better for nonproduction tapping." BUT......

For a lot of reasons that (I think anyway) mostly have to
do with marketing and production savings from only having
to do one kind of heat treatment, "carbon steel" taps tend
to be cheaply made and not as good as HSS taps. But this is
not always the case.... you can buy Greenfield carbon steel 
dies, for example, that are atleast as expensive as
imported HSS dies and will outlast the HSS dies (in 
nonproduction environment) many times over.

You might look at Leo StClair's, The Design and Use of
Cutting Tools, or Tool Steel Simplified by Carpenter Steel 
(mentioned previously) for more information. But in general,
the ONLY thing that HSS gives you over a different carbon
steel is red hardness. And you don't care about that with
a tap or a die, if used by hand.

IMHO of course :-)

/Charlie
for example, that are