lathe tools



Even if you buy ready made tools they will rapidly need to be sharpened so you would still need a grindstone and learn how to use it. One might as well go the whole hog and grind your own from the start.
Cliff Coggin.
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If you want to get straight to turning then, buy HSS tools ground to the conventional shapes. Learn to keep them sharp to begin and in the background, practice grinding your own.
I like Spareys book "The Amateurs Lathe". Some of it is out of date, I find the the tool profiles work and I now only ever use carbide indexable tip (not brazed tip) for cast iron and HSS for everything else. I don't use any exotic materials in my projects (yet!).
So long story short, stick with HSS and learn to use the grinder. The trickiest ones are the round nosed tools, but it's just patience and practice in the end.
And a golden rule, if you haven't got the right profile tool, start with a new blank, don't modify an existing one otherwise you end up never having the right profile!!!
Steve
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On Thu, 22 May 2008 02:43:58 -0700 (PDT), bert

Personally I prefer replaceable tip tools, and would have them anytime over basic HSS blanks.
Nice to learn how to sharpen tools etc etc., but in practice I prefere to have a new tip at the twist of an Allen key.
Peter -- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk http://www.prepair.co.uk http://www.prepair.eu
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I started out with HSS blanks and grinding my own, bought a set of indexable tips and now use HSS home ground again, leaving the carbide tips for roughing cast iron. It's a hobby for me and the grinding I find a great de-stresser! (not distressing). I find it easier to get a good finish with sharp HSS rather than carbide.
Steve
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I might suggest you're not using the right carbide inserts then. To repeat, yet again, something I've posted many times over the years. Most carbide tips are designed for high powered machines and high volume work. For use on steel they have slightly rounded edges to create sturdiness and resistance to chipping and they rely on machine rigidity, horsepower and rpm to push them through the material being machined. What you need for small lathes and hobby use, regardless of the work material, is razor sharp edges which you'll only find on uncoated (usually) non-ferrous carbide inserts. Edges very similar to what you'd grind on HSS anyway. They will generally be bright silver or perhaps carbide grey. If the tips you are using are gold, black or any other dark colour they won't cut worth a damn on a small lathe on most materials. They'll just push off the work and tear it to shreds. What you have to appreciate is that what the carbide insert manuals and guidelines mean by finishing cuts on a CNC lathe are still probably deeper cuts than the roughing cuts most of us use on manual lathes.
If you stick with inserts designed for aluminium you'll get perfect results on steel, cast iron, brass, bronze and just about anything else you want to tickle away at a few thou at a time on a small lathe and the inserts will last almost indefinitely if you don't abuse them. HSS might get the same finish but it'll blunt every five minutes. If you want to take 4mm deep cuts in EN40B then sure you need 10 hp and an insert designed for roughing steel.
I use a single carbide insert turning and facing tool with non ferrous tips for 95% of the work I do on my Student. HSS has its uses when you need to grind a special shape or make a very small boring tool for a one off job but for most turning and facing I'd say get the largest shanked tool your lathe can accept, some sharp non ferrous inserts to fit it and you can forget buggering about on bench grinders every five minutes for the rest of your life.
My mate's 50,000 CNC lathes can use a steel specific, rounded edge insert and still get a mirror finish on hard materials like EN52B and 21/4N valve steels. If I try to use the same insert on my Student it just buggers everything it touches. My 40 year old machine has 50 times the backlash his new ones do though, half the rpm, one tenth of the hp and no coolant. It's just a matter of horses for courses.
If you want to spend your life learning how to sharpen tools rather than actually cut metal then HSS is the very thing. You'll just die very accomplished rather than having ever made anything.
--
Dave Baker
Puma Race Engines
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wrote:

I completely agree. Whilst you can get a better finish with HSS on a small lathe, the only thing I use HSS for on my ML7 is screwcutting. Everything else I use carbide insert tips.
My favourite tool is one of these: http://www.greenwood-tools.co.uk/ishop/728/shopscr16.html with a Sandvik GC4025 insert with a 0.2 radius tip. This grade is designed for stainless but works pretty much perfectly for just about anything.
And if I need a *really* fine finish or half a thou' or so taken off, then I use an SCLCR holder with a CCGT insert made for aluminium, like this:
http://www.cnccookbook.com/img/OthersProjects/Tools/CCGPInsert.jpg
works fine, even on stainless. (ignore the mispelt 'CCGP' in the link).
Life's too short and time in workshop too limited to spend all your time grinding HSS, albeit this is defintely a usefull skill to have. However, if you get the HSS grind wrong - which beginners always do- then you'll be constantly frustrated with the poor cutting ability and lousy finish until you get it just right.
Peter
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Peter Hi, a friend of mine by way of a gift of a couple, introduced me to the CCGT (aluminium) inserts a while ago when I still had time to go into the workshop. In planning a return to work :-), I haven't yet found an economic source (ie less than 5 each), have you - or is it one of those instances that the bullet just has to be bitten?
Regards
Keith (short of both time and money)
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On Fri, 23 May 2008 12:22:36 -0700 (PDT), jontom snipped-for-privacy@hotmail.com wrote:

Keith, sent you an e-mail. Much cheaper than 5 a pop <G>
Peter
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Peter - wouldn't mind the same pointer -
eMail is good
Steve
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Steve wrote:

me too!
Alternatively, does anyone have any for-aluminium TPUN or TPMR 11030x / 22x inserts I could try? Beer tokens ok.
-- Peter Fairbrother
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On Sat, 24 May 2008 03:25:20 +0100, Peter Fairbrother

Peter, it's no secret really, but I buy mine from e-bay, you just have to keep an eye out for them. I e-mailed Keith rather than posting here at first as there are some up for sale on there now.
About 2 years ago I bought a pack of Walter (brand) CCGT's from e-bay. These are 09's, so need a 12mm shank holder, but these things are mirror polished with a coppery coating, and are sharper than the point on a demons tail. Talk about a lucky find, as I hadn't heard of Walter before, but they will shave the hair off a gnats b***s without breaking the skin. They weren't dear either, and I've since bought another 2 packs at around 12-15 to keep for the future, as the Walters don't seem to come up that often. Mine supposedly have a 0.4 nose rad, but it feels like a much sharper one than that. There are some sandvik CCGT's on at the moment, listing here: http://cgi.ebay.co.uk/10-Sandvik-Carbide-Turning-Inserts-CCGT-09T308-UR_W0QQitemZ380008837407QQihZ025QQcategoryZ112399QQrdZ1QQssPageNameZWD1VQQcmdZViewItem and here http://cgi.ebay.co.uk/10-Sandvik-Carbide-Turning-Inserts-CCGT-120408-UR_W0QQitemZ380008837355QQihZ025QQcategoryZ112399QQrdZ1QQssPageNameZWD1VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247 both for 14.95 at 'buy-it-now', but both also have 0.8 nose rad, so I don't know how they will compare to the Walters. Even though they are meant for aluminium they work brilliantly with mild steel and alloy steel like EN19 and 316 stainless for a finishing cut.
Peter
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On or around Sat, 24 May 2008 07:12:46 +0100, Peter Neill

So, how do you tell they're for aluminium?
is that the UR bit?
flaming codes are like a gordian knot.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
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After reading all the posts on lathe tools and grinding HSS I think on our club stand at Harrogate next year I should take a grinder and some HSS blanks and show people how to grind tools by hand. No jigs, no gauges. It would only take a few minutes per person to get them started. Once you know what you are after doing that's the hardest part done. Of course we would not have to tell the people selling tips. If not a grinder on the stand we could be available to talk to people and have a few sketches and tools we had ground. It might help someone. I might start taking some tools to the steam rallies I go to so people can see how it is done. Bill

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While at the Dutch engine rally in Nuenen a week or so ago, we picked up a small boring bar and a new box of DCMT tips for a reasonable price.
We already have an external tool holder that takes the same tips, so we are now more or less set up for our workshop Raglan Littlejohn lathe.
We also have a selection of standard Jones & Shipman boring bars which we mangle the tools for occasionally.
Peter -- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk http://www.prepair.co.uk http://www.prepair.eu
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When I bought my first lathe (an old ML7) in 1982 it came with a giant box of HSS bits, literally hundreds of them, and I have been using them ever since. As has been said, regrinding them freehand on an offhand grinder is relativly easy, they are cheap and you can also make odd shapes as well. Having built a Worden grinder from the Hemmingway kit I can now grind the tool angles very accuratly and repeatably as well. A few years ago however on a whim I bought a couple of Arrand indexable turning tools and these are superb. The tips last for ages, give a good finish and are hard enough to easily deal with things like chilled areas on cast iron castings. If I was starting from scratch (and had the money) I would invest in a set of quality indexable tools such as Arrand or the ones available from Greenwood Tools and leave the HSS for the special jobs.
--
lfoggy
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Bill wrote:

Bill, I think that is a wonderful idea.
An awful lot of us that have some experience, have forgotten how daunting it all looks from the outside, as it were.
As I butchered a quote earlier, a decent demo is worth a thousand questions.
One of the very first tools I get the apprentices to make, is a simple grind of 5 degrees back from the point, on the end, the cutting side (either towards or away fron the headstock) and with a compound grind on the top face, with 5 degrees top and back rake. I have then us a protractor, and a Sharpie marker to lay it out.
Not really optimal for any one material, but it provides a sharp edge that is easy for them to get their heads around.
Typically, I have them stome a .010" radius on the tip, too.
I have the benefit of an optical comparator for them to see the lines and angles with, and to measure the radius, but I show them how to do as well using a loupe and a Micrometer to get as close as they can to a size.
Cheers Trevor Jones
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Bill wrote:

Good idea - someone showed me, took about ten minutes, and it then took me a couple of hours of solo practice before I was grinding good working tools, every time, by eye.
Might take me a couple of tries now to get new type of tool cutting right, especially if I've never seen it in the flesh.
But that's all it takes.
-- Peter Fairbrother
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On another thread ('I'm sure this has been asked before') is a link to a site (shopswarf). This has the lathe cutting angles for HSS.
http://shopswarf.orconhosting.net.nz/turntool.html
Best regards, Dave Colliver. http://www.AshfieldFOCUS.com ~~ http://www.FOCUSPortals.com - Local franchises available

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Peter Neill wrote:

In the shop I work in, and as often as not, have to train apprentices in, we do a lot of work that does not need the production rates as much as we need the precision.
We often have jobs where there are no practical carbide inserts available (or they are silly money!) where HSS tools are quite capable of being used.
As a result, we still teach a lot of grinding, as a basic skil, so that they will be able to, if they get to a job that can be done no other way.
I'm going to see about ordering in a package or two of those CCGT inserts for or boring bars, though, and perhaps a few lathe tool holders to suit.
As someone else said, horses for courses!
I beleive that a beginner is better served to learn to turn with a tool that does not readily chip, and is relatively inexpensive, anf forgiving to use. HSS suits what I need it to do at home on my S-7, for most things, though I have a few carbide tools around that I can use.
As to being at the grinder every few minutes. Not so much. I am finding that tools will last sometimes for several hours use, now that I do not do as many beginners mistakes. Regrinding a tool, is a good time to contemplate what happened, and how to not have it happen again. :-)
Now, learning to TIG weld! There is a way to teach yourself tolerance! And electrode grinding!
Thanks!
Cheers Trevor Jones
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enlightened us thusly:

It depends what I'm doing. If I'm trying for a precise fit on something, I use coolant to stop the job heating up and therefore expanding. In the past, I've cut things that got fairly hot to an exact size (this is for something that's a tightish push fit) and then, when it's got cold, it's not the fit I wanted.
generally, though, I only use coolant if it seems like it needs it. Tend to use it for parting things.
--
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
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