Subject: Old technology

From: [email-masked] (Russ Kepler)
Date: Tue, 18 Oct 1994 03:53:12 GMT

I've been puzzling over something a bit strange: why does virtually
every metalworking reference book I have (and I spend a *lot* on
books) not contain any "recent" lathe tool shaping?  Virtually all of
the references completely neglect chip breaking grooves, and focus on
grinding single point insert tools, this when virtually every tool I
see make for normal diameter reduction is just a couple of grinds from
a 3/8" or 1/2" square M2 blank?

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

                      Please don't feed the Engineers

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From: [email-masked] (John Morton)
Date: 18 Oct 1994 15:50:07 GMT

In article <[email-masked]>,
>a 3/8" or 1/2" square M2 blank?

You bring up some interesting points.  On the one hand, books on "old
technology" are the only ones I find interesting, because they feed
my machinist-need to maintain an ability to make things from scratch.
That is what the trade is all about.

On the other hand, certain important things have never made it into
books; I don't know why.  Neither old nor new books give a satisfactory
treatment of tool grinding, unless you extrapolate the world of lathe
tools just from first principles.  As far as I know, tool grinding is
learned from other machinists, and that's the way it's always been.
I have over a hundred toolbits in my toolbox drawer, and _none_ of them
look like the ones in a book :-).

Conclusion:  machinists don't use reference books.

John Morton			     Mechanical Engineering Machine Shop
[email-masked]	     University of California at Berkeley

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From: [email-masked] (Russ Kepler)
Date: Thu, 20 Oct 1994 04:03:45 GMT

In article <[email-masked]>,
John Morton <[email-masked]> wrote:
>BTW I do use a shop library, but it consists mainly of subjects peripheral
>to what I do, e.g. die design, non-conventional machine processes,
>codes and specifications, mechanical motions, properties of materials,
>catalogs.  A good jigs and fixtures book can come in handy.  

But just try to find one that references using a 1-2-3 block.

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From: [email-masked] (John Morton)
Date: 19 Oct 1994 21:47:01 GMT

In article <[email-masked]>, Tala Brandeis <[email-masked]> wrote:
>
>Well, it helps to have a desire to know everything about metalworking
>as a prerequisite to *finding* the info.  When I started it was
>impossible to get informtion out of the older machinists, even when
>they knew something.  

Unfortunately this is often the case.  All of my important learning
experiences were isolated occasions when I had somehow established enough 
of a relationship to an expert to get some advice out of him.
>>books; I don't know why.  
>When I learned something, not everyone *wanted* to know what I'd 
>learned.  Few of them wanted to take the time to learn it.  Most
>of them had work to do on their own.  In training others most were
>afraid of trying something new.  Many of the techniques with respect

Yes, production is the operative principle.  For this reason it is often
the foreman who is in a position to troubleshoot your setups, if you
are so lucky that the guy knows what he's talking about :-).  "Trying
something new" often means pushing some limitation until you break
something, then backing off a bit - all because the boss is on your case.

>>learned from other machinists, 
>...
>Some do and some have.  The world is full of different experiences
>and different people.  We all have our ways of finding the information
>we want and need.  

Each one of us knows only a small part of the trade as it is practiced.
I'll retract my pompous conclusion and assume that you and others have
actually come across a machinist consulting a tool-grinding book :-).

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From: [email-masked] (Russ Kepler)
Date: Thu, 20 Oct 1994 03:36:54 GMT

In article <[email-masked]>,
>That is what the trade is all about.

Sure, I like those as well (I get all too many charges from Lindsey's)
but to find a book that addresses cemented carbide bits is almost
exceptional and a book that addresses indexable carbide insert
tooling, well, that's not easily found (the only one I have is
_Machine Shop Practice_ and there it's a brief section - I've found
more information in catalogs.  Even in that book the major part of the
chapter is spent in describing how to grind up a rough turning tool,
and I've seen a lot better one.

The book goes into grinding a 15deg side rake, a 5deg back rake and a
10deg relief.  all in all it's a lot easier to grind on a chip
breaking groove that intersects the cutting face with a 15deg angle
and to relieve the areas below the cutting edge and the front of the
bit.  Properly done (in less than a minute) you have a superb roughing
tool.

>look like the ones in a book :-).

I guess so - it took an old machinist to show me the above.  The same
fellow lets me borrow his surface grinder to get the cut off tools
*just* *right*.  I'm proud that the first time we ran one of my hand
carved tools through it was just a cleanup and not a regrind.

>Conclusion:  machinists don't use reference books.

Interestingly enough I managed to stumble along without _Machinery's
Handbook_ for a lot longer than I should.

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From: [email-masked] (Tala Brandeis)
Date: 19 Oct 1994 10:58:33 -0700

When I learned something, not everyone *wanted* to know what I'd 
learned.  Few of them wanted to take the time to learn it.  Most
of them had work to do on their own.  In training others most were
afraid of trying something new.  Many of the techniques with respect
to grinding a tool were full of the experience of having ground many
tools prior to the shape I'd settled on for the work and the machine.
That type of learning is somewhat unique as a technology and lends
itself poorly to automated intellegence.  

>Neither old nor new books give a satisfactory

And from books and especially from the informed process of *needing*
to do it differently and *working* to make that happen, including the
research into old technical volumes.  

>and that's the way it's always been.

[email-masked]

-- 
 Tala Brandeis, 2215-R Market Street, Suite 247, SF, CA, 94114-1612

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From: [email-masked] (Nick Turner)
Date: Wed, 19 Oct 94 08:57:33 GMT

>tools just from first principles.  

people often make the grind more complicated than is nessercery. and it can 
be wastful of material and time I find that the simplest profile that will do 
the job often works the best, I don't have as much call for grinding 
tools as I did. I don't think that I would ever grind a chip beaker into a 
tool if I could avoid it as it would cause waste in subsequent sharpenings.
And when I do need a tool that chips I use an insert with the profile that 
I need .

As far as I know, tool grinding is
>learned from other machinists, and that's the way it's always been.

Then it evolves with each machinist.

>look like the ones in a book :-).

Never the one that you need for the job. :-)

Nick

--

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From: PAUL <[email-masked]>
Date: Fri, 21 Oct 94 21:16:51 -0500

The textbook editors depend upon Manufacturers research for their info. If you
require any specs for the enwer Carbide Tooling, call a local supplier. They
have "tons" of info supplied by their manufacturers.