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Posted by Austin Shackles on May 24, 2008, 7:13 am
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On or around Fri, 23 May 2008 13:01:25 GMT, Trevor Jones
> An eight year old can learn to grind a decent tool. It is an
>elementary level skill.
> All new skills come with a learning period. Best to get it over and done!
anyone care to point to a decent place to get tips on this, ideally online?
Or if there isn't such an online resource, does anyone fancy having a go at
producing one? While I mostly make tools that work, it sometimes takes more
than one "go" and I daresay mine could be better if I knew a bit more about
it - I expect most of us end up with a tool that does the job adequately
rather than well, quite often.
I have one indexed tool, for general turning and one indexed boring bar. I
like the carbide tool for the fact that it stays sharp, it's difficult to
bugger up by cutting too fast or inadequate coolant, and it's dead quick and
easy to get a really sharp edge, you just change the insert, or turn it
round to get a new cutting edge.
Downsides, as others have said: it's an expensive way of doing it: a single
half-inch square HSS tool will last for ages, and costs little (although, to
be complete, you should factor the grinding wheels and the electricity the
grinder uses into the cost).
Carbide tips also last quite a while but they're difficult to say the least
to sharpen credibly, they break if you're careless and they cost quite a lot
to replace. The general turning tool I use has a CCMT09 insert and they
cost several pounds each for decent ones, as much as a whole half-inch HSS
tool, which will last much longer unless you do something really stupid with
it.
Now, I've just given the impression that I only use 2 tools, both indexed.
That's not really true. Okay, a lot of the time I do use just the one tool,
but then a lot of the time that's a good tool for the job. In fact, if you
come and look at my lathe, chances are the normal indexed 75° tool is on one
side of the toolpost and the parting-off tool is on the opposite side. But
that just reflects that these are the tools I use most often.
I have quite a few other HSS tools, some of which came with the previous
lathe, and some of which I bought. I also have a parting tool with an HSS
blade. I use the HSS tools primarily for anything that needs a non-standard
shape or angle. The most recent one was a funny pointy tool to turn the
reverse chamfer I mentioned in the post about the pipe bulging tool I made.
This requires an odd set of angles on the tool which you'd not get on an
indexed tool anyway - technically, it could be done with triangular insert
but the small diameter would mean there wouldn't be enough clearance below
the cutting face. On the HSS tool, that just meant a bit more grinding.
Other things I've got HSS tools for are machining circlip grooves (a very
very thin cutting edge, only cuts about 1mm deep and on the end of a 1/2"
tool - took a bit of grinding, that one, but invaluable once done, also
tools with large radii on the end, tools that leftwards instead of
right-wards, one that cuts a semicircular 2mm groove, and so on. All of
these had a special use at the time, and some are still in use. Or they get
re-ground to a different shape for the next special job. For this sort of
turning, you can't beat HSS unless the material to be worked is simply too
hard.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
------------------------------------------------
>> http://www.schlockmercenary.com/ << ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!
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Posted by Trevor Jones on May 24, 2008, 12:58 pm
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Austin Shackles wrote:
> On or around Fri, 23 May 2008 13:01:25 GMT, Trevor Jones
>
>
>> An eight year old can learn to grind a decent tool. It is an
>>elementary level skill.
>> All new skills come with a learning period. Best to get it over and done!
>
>
> anyone care to point to a decent place to get tips on this, ideally online?
> Or if there isn't such an online resource, does anyone fancy having a go at
> producing one? While I mostly make tools that work, it sometimes takes more
> than one "go" and I daresay mine could be better if I knew a bit more about
> it - I expect most of us end up with a tool that does the job adequately
> rather than well, quite often.
>
Take a look at the Sherline website. www.sherline.com IIRC.
Several hundred pages, mostly devoted to very small lathe and milling
machine work.
There are a couple pages of info on tool grinding there, that are
worth a look.
If you are not on a dial-up account, search around and find a copy of
the South Bend Lathe book, How to Run a Lathe. Tool shapes are covered
there pretty well.
A copy of this book in hard copy form, can usually be found for under
$20 on this side of the ocean (Lee Valley Tools sels a older version for
$10) and I am pretty certain it is available from the booksellers in the
UK. Same book, is the Boxford manual, titled, IIRC, Know your Lathe.
I usually steer beginners towards 3 UK published books to start off.
The two Tee Publications books (or whomever has taken over that line)
Workholding in the Lathe, and Milling operations in the Lathe, by Tubal
Cain, and The Amateur's Lathe by Sparey. Between them, they cover a LOT
of ground, and show that many things are possible with limited tooling.
Cheers
Trevor Jones
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Posted by dave sanderson on May 24, 2008, 2:35 pm
Please log in for more thread options > Austin Shackles wrote:
> > On or around Fri, 23 May 2008 13:01:25 GMT, Trevor Jones
>
> >> An eight year old can learn to grind a decent tool. It is an
> >>elementary level skill.
> >> All new skills come with a learning period. Best to get it over and done!
>
> > anyone care to point to a decent place to get tips on this, ideally online?
> > Or if there isn't such an online resource, does anyone fancy having a go at
> > producing one? While I mostly make tools that work, it sometimes takes more
> > than one "go" and I daresay mine could be better if I knew a bit more about
> > it - I expect most of us end up with a tool that does the job adequately
> > rather than well, quite often.
>
> Take a look at the Sherline website.www.sherline.comIIRC.
>
> Several hundred pages, mostly devoted to very small lathe and milling
> machine work.
>
> There are a couple pages of info on tool grinding there, that are
> worth a look.
>
> If you are not on a dial-up account, search around and find a copy of
> the South Bend Lathe book, How to Run a Lathe. Tool shapes are covered
> there pretty well.
>
> A copy of this book in hard copy form, can usually be found for under
> $20 on this side of the ocean (Lee Valley Tools sels a older version for
> $10) and I am pretty certain it is available from the booksellers in the
> UK. Same book, is the Boxford manual, titled, IIRC, Know your Lathe.
>
> I usually steer beginners towards 3 UK published books to start off.
>
> The two Tee Publications books (or whomever has taken over that line)
> Workholding in the Lathe, and Milling operations in the Lathe, by Tubal
> Cain, and The Amateur's Lathe by Sparey. Between them, they cover a LOT
> of ground, and show that many things are possible with limited tooling.
>
> Cheers
> Trevor Jones
I agree with the sherline pages, I learnt to grind tools following
this:
http://www.sherline.com/grinding.htm One thing I disagree with however
is the recommendation to have a cup of water to dip the blank in if it
gets to
hot (pretty sure it was this article). Dipping hot HSS into water can
cause micro
cracking of the steel. The water cooling is a throwback to Carbon
steel tools
HSS should be ground hard and quickly, faffing about taking light
passes wastes
time, and heats the blank excessively.
My top tip: clamp the tool blank in a pair of mole grips and have at
it, you wont
burn your hands, and its virtually impossible to draw the temper on a
good HSS
blank. grind it hard and fast to approximatly the correct shape and
then tune it up
on the other wheel, and finally (if you need a good finish) a diamond
'stone'
Dont worry to much about the angles, they are to aim for, not gospel.
The correct shape is one where the first and only bit that contacts is
the cutting edge.
Dave
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Posted by Trevor Jones on May 24, 2008, 4:54 pm
Please log in for more thread options dave sanderson wrote:
>
>>Austin Shackles wrote:
>>
>>>On or around Fri, 23 May 2008 13:01:25 GMT, Trevor Jones
>>
>>>>An eight year old can learn to grind a decent tool. It is an
>>>>elementary level skill.
>>>>All new skills come with a learning period. Best to get it over and done!
>>
>>>anyone care to point to a decent place to get tips on this, ideally online?
>>>Or if there isn't such an online resource, does anyone fancy having a go at
>>>producing one? While I mostly make tools that work, it sometimes takes more
>>>than one "go" and I daresay mine could be better if I knew a bit more about
>>>it - I expect most of us end up with a tool that does the job adequately
>>>rather than well, quite often.
>>
>> Take a look at the Sherline website.www.sherline.comIIRC.
>>
>> Several hundred pages, mostly devoted to very small lathe and milling
>>machine work.
>>
>> There are a couple pages of info on tool grinding there, that are
>>worth a look.
>>
>> If you are not on a dial-up account, search around and find a copy of
>>the South Bend Lathe book, How to Run a Lathe. Tool shapes are covered
>>there pretty well.
>>
>> A copy of this book in hard copy form, can usually be found for under
>>$20 on this side of the ocean (Lee Valley Tools sels a older version for
>>$10) and I am pretty certain it is available from the booksellers in the
>>UK. Same book, is the Boxford manual, titled, IIRC, Know your Lathe.
>>
>> I usually steer beginners towards 3 UK published books to start off.
>>
>> The two Tee Publications books (or whomever has taken over that line)
>>Workholding in the Lathe, and Milling operations in the Lathe, by Tubal
>>Cain, and The Amateur's Lathe by Sparey. Between them, they cover a LOT
>>of ground, and show that many things are possible with limited tooling.
>>
>> Cheers
>> Trevor Jones
>
>
> I agree with the sherline pages, I learnt to grind tools following
> this:
> http://www.sherline.com/grinding.htm One thing I disagree with however
> is the recommendation to have a cup of water to dip the blank in if it
> gets to
> hot (pretty sure it was this article). Dipping hot HSS into water can
> cause micro
> cracking of the steel. The water cooling is a throwback to Carbon
> steel tools
> HSS should be ground hard and quickly, faffing about taking light
> passes wastes
> time, and heats the blank excessively.
> My top tip: clamp the tool blank in a pair of mole grips and have at
> it, you wont
> burn your hands, and its virtually impossible to draw the temper on a
> good HSS
> blank. grind it hard and fast to approximatly the correct shape and
> then tune it up
> on the other wheel, and finally (if you need a good finish) a diamond
> 'stone'
> Dont worry to much about the angles, they are to aim for, not gospel.
> The correct shape is one where the first and only bit that contacts is
> the cutting edge.
>
> Dave
>
I show the guys the mole grip/ vice-grip technique.
From what I read, the microfracturing of the surface tends to come
about from dropping the red hot tool bit into the water.
I tell folks to consider that HSS will hold a cutting edge at red
heat, and that for the most part, they cannot hurt the tool blank enough
to affect the way it cuts, by anything they do with a grinding wheel.
A dip tank is nice, for when you have ground away the most of the
tool, and you have to get down to the fine bits of work, and you want to
be able to hold the tool bit by hand.
It's amazing, how heavy those little bits can be, when they have been
in contact with the wheel for a few seconds! :-)
Cheers
Trevor Jones
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Posted by dave sanderson on May 24, 2008, 5:15 pm
Please log in for more thread options > dave sanderson wrote:
>
> >>Austin Shackles wrote:
>
> >>>On or around Fri, 23 May 2008 13:01:25 GMT, Trevor Jones
>
> >>>>An eight year old can learn to grind a decent tool. It is an
> >>>>elementary level skill.
> >>>>All new skills come with a learning period. Best to get it over and done!
>
> >>>anyone care to point to a decent place to get tips on this, ideally online?
> >>>Or if there isn't such an online resource, does anyone fancy having a go at
> >>>producing one? While I mostly make tools that work, it sometimes takes more
> >>>than one "go" and I daresay mine could be better if I knew a bit more about
> >>>it - I expect most of us end up with a tool that does the job adequately
> >>>rather than well, quite often.
>
> >> Take a look at the Sherline website.www.sherline.comIIRC.
>
> >> Several hundred pages, mostly devoted to very small lathe and milling
> >>machine work.
>
> >> There are a couple pages of info on tool grinding there, that are
> >>worth a look.
>
> >> If you are not on a dial-up account, search around and find a copy of
> >>the South Bend Lathe book, How to Run a Lathe. Tool shapes are covered
> >>there pretty well.
>
> >> A copy of this book in hard copy form, can usually be found for under
> >>$20 on this side of the ocean (Lee Valley Tools sels a older version for
> >>$10) and I am pretty certain it is available from the booksellers in the
> >>UK. Same book, is the Boxford manual, titled, IIRC, Know your Lathe.
>
> >> I usually steer beginners towards 3 UK published books to start off.
>
> >> The two Tee Publications books (or whomever has taken over that line)
> >>Workholding in the Lathe, and Milling operations in the Lathe, by Tubal
> >>Cain, and The Amateur's Lathe by Sparey. Between them, they cover a LOT
> >>of ground, and show that many things are possible with limited tooling.
>
> >> Cheers
> >> Trevor Jones
>
> > I agree with the sherline pages, I learnt to grind tools following
> > this:
> >http://www.sherline.com/grinding.htmOne thing I disagree with however
> > is the recommendation to have a cup of water to dip the blank in if it
> > gets to
> > hot (pretty sure it was this article). Dipping hot HSS into water can
> > cause micro
> > cracking of the steel. The water cooling is a throwback to Carbon
> > steel tools
> > HSS should be ground hard and quickly, faffing about taking light
> > passes wastes
> > time, and heats the blank excessively.
> > My top tip: clamp the tool blank in a pair of mole grips and have at
> > it, you wont
> > burn your hands, and its virtually impossible to draw the temper on a
> > good HSS
> > blank. grind it hard and fast to approximatly the correct shape and
> > then tune it up
> > on the other wheel, and finally (if you need a good finish) a diamond
> > 'stone'
> > Dont worry to much about the angles, they are to aim for, not gospel.
> > The correct shape is one where the first and only bit that contacts is
> > the cutting edge.
>
> > Dave
>
> I show the guys the mole grip/ vice-grip technique.
>
> From what I read, the microfracturing of the surface tends to come
> about from dropping the red hot tool bit into the water.
> I tell folks to consider that HSS will hold a cutting edge at red
> heat, and that for the most part, they cannot hurt the tool blank enough
> to affect the way it cuts, by anything they do with a grinding wheel.
>
> A dip tank is nice, for when you have ground away the most of the
> tool, and you have to get down to the fine bits of work, and you want to
> be able to hold the tool bit by hand.
>
> It's amazing, how heavy those little bits can be, when they have been
> in contact with the wheel for a few seconds! :-)
>
> Cheers
> Trevor Jones
If I need to hold onto it I often use a welding glove, first time I
ground a tool bit
I put it down and then picked up the wrong end... Owowowowow...
Dave
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>elementary level skill.
> All new skills come with a learning period. Best to get it over and done!