Author Topic: HSS Tool Sharpening  (Read 11794 times)

Arbalest

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HSS Tool Sharpening
« on: October 31, 2012, 11:20:13 AM »
Stumbled across this and though others may find it useful. Will be making the "puck" jig very soon!

http://conradhoffman.com/advancedsharp.htm

http://conradhoffman.com/shop_images/thread_tool_fixture.PDF

Also check out the home page, lots more useful stuff!


Goldstar31

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Re: HSS Tool Sharpening
« Reply #1 on: October 31, 2012, 12:44:38 PM »
Thank you, I've also stumbled across this and found it quite absorbing.
It really hearkens back to Jacob Holzapffel and his goniostat which appears in hs ornamental turning books- in the dark and distant past. They are on the net somewhere-free. A lot of discoveries of today are actually in there to read and digest from a day when he sold an Ornamental turning lathe to the Tsar of Russia- before the Russian Revolution in 1917!
However, the Goniostat is far beyond the average abilities and that is merely to construct one.

Somewhere, I have details of a much similar machine but with graduations which came from a gentleman in the Society of Ornamental Turners and the constructional drawings are from  Mike Fallows in Ornamental Turners International's web site.

This always assumes that one has either the old abrasives- in neat little boxes or in syringes full of assorted diamond pastes( also Russian?) I've been a cheating because dear old Holzapffel actually used a machine to get rid of the tedium. So did I, I have a set of diamond wheels that transfer across from the various tool and cutter grinders which I set up to do various tools.

Thank you, for the opportunity to add a few of my own thoughts along these lines.

Norman

Offline black85vette

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Re: HSS Tool Sharpening
« Reply #2 on: October 31, 2012, 03:29:24 PM »
Interesting article.   :ThumbsUp:   When I took a basic machine shop class the instructor was a retired machinist.    He told us; "I'm going to show you how to grind a tool, but, you won't really need to know how to do this because you will be using indexed tools on CNC machines".   In reality that lesson was one of the most useful of the class.  Still use that skill today.

Offline zeeprogrammer

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Re: HSS Tool Sharpening
« Reply #3 on: November 01, 2012, 01:41:09 AM »
Interesting links Arbalest. Thanks for posting them.
Reminds me I need to take some time and learn more about grinding my own tools. Soon.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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Offline ScroungerLee

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Re: HSS Tool Sharpening
« Reply #4 on: November 01, 2012, 01:14:25 PM »
I think a lot of people view grinding tools as a black magic art, especially when they see diagrams showing exact degrees of angles.  From my few years hand grinding tools I have decided that level of perfection is not really required for me, I grind by eye getting as close as I can to the angles desired.  I don't go nuts measuring if something is 7 degrees or 9.

Maybe I would see an improvement and I don't realize what I am missing?  Either way I have been wanting to make a fixture for my belt grinder for sharpening lathe bits.

Lee
Mmmmm.... Shiny!

Offline Jo

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Re: HSS Tool Sharpening
« Reply #5 on: November 01, 2012, 01:37:50 PM »
If you want to learn about what makes a good tool and a bad tool grind I recomend trying to turn using a very small lathe like my Cowells. For years I thought that HSS was  :censored: then I got my Cowells and the restricted tool size meant that I had to learn to grind tools.

Ok I have not learnt, what I have done is finally get around to making the adapters to allow me to grind a lump of HSS on my cutter grinder and  :o what a difference. I am now a convert and the tipped tools are second choice.

Jo
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Offline b.lindsey

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Re: HSS Tool Sharpening
« Reply #6 on: November 01, 2012, 01:59:15 PM »
I have to agree with Jo....for most of the materials we commonly use, I get much better results using HSS, be it with a diamond toolholder or just ground blanks. Thats not to say I haven't used cemented carbide at times or even inserts on occasion. As funds permit, I would like to purchase a set or A.R. Warner tools for my Sherline with HSS inserts...best of both worlds in a way. I do have one of their boring bars and love it!!  Usual disclaimers.

Bill

Offline bp

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Re: HSS Tool Sharpening
« Reply #7 on: November 02, 2012, 12:05:14 AM »
After screwcutting some 4140 with an HSS tool the cutting edge of the tool was stuffed.  So I made a version of Bruce Hoffmans "puck".  Mine was out of a bit of Al. Alloy, because I had it, and I used a diamond credit card size hone.  It worked a treat.  I've just screwcut a piece of EN36a and the freshly honed tool cut a beautiful thread.  Now thinking about a "puck" for normal HSS tools.
cheers
Bill

Offline NickG

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Re: HSS Tool Sharpening
« Reply #8 on: November 02, 2012, 03:19:22 PM »
I've always had better results with self ground tools - still not great at doing them and only have the facility to do them by eye. I've seen some people put a grind stone in the lathe chuck and use the compound slide to get angles right but not sure whether this is good practise or not. My lathe max speed is 720rpm which I rarely need to go up to so doubt it'd be fast enough for a grind stone. Probably also the reason my lathe prefers HSS.

Nice link, will have a proper read through that.

Arbalest

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Re: HSS Tool Sharpening
« Reply #9 on: November 02, 2012, 05:33:28 PM »
Glad it's been of interest. I don't have trouble freehand grinding tool bits for general turning but the "puck" jig seems a great idea for final sharpening of thread cutting tools.

Goldstar31

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Re: HSS Tool Sharpening
« Reply #10 on: November 02, 2012, 05:59:27 PM »
Nick, you need something around 3000 rpm for a 6" wheel and  my tool and cutter grinders go at 2 times 2880 rpm with smaller wheels that are rated for up to 7000rpm which is 10 times beyond what your lathe can.

Frankly, I'd go for a 6" Double ended grinder from places like Lidl or Aldi when they are on offer. However, you should change the stones and the tool rests. I'd go for say 80 to 100 grit in white aloxite and 60 ish to rough out.

Probably, Cromwell Tools would supply the wheels.

If you want to use your lathe and have a face plate, I'd put a dummy of say aluminium on it and use a diamond paste say a green one to lap a lathe tool to a superb sharpness after your time on the DE Grinder.

I don't do exactly that but with limited gear as you mention, I would try it. Be surprised!

Offline Tin Falcon

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Re: HSS Tool Sharpening
« Reply #11 on: November 03, 2012, 04:31:42 PM »
that puck is an interesting tool.
I have gotten pretty good at grinding HSS bits. IMHO the best choice for hobby lathes.  not knocking carbide but carbide likes speed and speed requires power. most hobby lathes just do not have either the speed or power requirements to really utilize carbide.
south bend used to have a block for holding hss bits to grind them I will see if I can find the design an redraw it.
the other thing is many of us use flat qc tool holders . it would be wise for those of us who make our own tool holders to build in the back rake.  Warner tool sells one that fits the OAX A2Z qctp.
and I have to say the warner tools work great and hold an edge quite well I have a couple of sets one set for several years and I have yet to replace or discard an insert . Idon ot machine a lot but it is my most used tool.
Tin

Offline ScroungerLee

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Re: HSS Tool Sharpening
« Reply #12 on: November 03, 2012, 04:51:13 PM »
QTCP tool holder with built in back rake, another why didn't I think of that moment.  Thanks for that!

Lee
Mmmmm.... Shiny!

Offline Tin Falcon

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Re: HSS Tool Sharpening
« Reply #13 on: November 03, 2012, 05:14:09 PM »
Here is what i am talking about.  I love when I search the net for something and find a post I wrote 5 years ago

take a look here
http://bbs.homeshopmachinist.net/threads/23403-South-Bend-Lathe-Tool-Grinding-Jig
Tin

Offline steamer

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Re: HSS Tool Sharpening
« Reply #14 on: November 03, 2012, 07:09:35 PM »
There is no link...or this link is broken.

Dave
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Offline Dan Rowe

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Re: HSS Tool Sharpening
« Reply #15 on: November 03, 2012, 07:13:28 PM »
Here is what i am talking about.  I love when I search the net for something and find a post I wrote 5 years ago

take a look here
http://bbs.homeshopmachinist.net/threads/23403-South-Bend-Lathe-Tool-Grinding-Jig
Tin

The link works for me. :ThumbsUp:

Dan
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Offline NickG

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Re: HSS Tool Sharpening
« Reply #16 on: November 04, 2012, 02:54:24 PM »
That's all I have at the moment, cheap  DE grinder. Guess could knock some sort of Jig up to use with it.

Offline Jo

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Re: HSS Tool Sharpening
« Reply #17 on: November 04, 2012, 04:20:19 PM »
I saw this very cheap tool sharpening jig that you might be interested in:





The two end plates provide the first angle and the owner had made up a number of wooden blocks that mounted at specific angles needed by the tool.

Jo
Usus est optimum magister