Which indexable lathe tools to get?

Any recommendations for indexable lathe tools to use on my Super C3 mini lathe? It's different to choosing drills because the cutting parts are
replaceable, so I think it makes more sense to get good tools right from the start. I'm not loaded, but I like the philosophy that buying good stuff in the first place save buying again so soon.
Scrim
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On Sun, 17 Oct 2010 02:35:16 +0100, Scrim wrote:

As it is a mini lathe why not use HSS tools and resharpen when needed?
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Neil - reverse 'ra' and delete 'l'.

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You get what you pay for. I've had my lathe for 5 years now and I've bought a load of stuff for it usually from the shows and regretted nearly all of the purchases I've made.
First set I bought were 8mm ones from Warco, I actually ordered the 10mm ones but they sent out the wrong set, The actual holder material is soft which allowed the tips to twist, I got round this problem by thread locking them on, second point is the crap tiny torx screws, they are made of chocolate and strip their threads in no time, I've since re-tapped to a larger size and use a Allen screw instead to hold them but still use a touch of loctite as well.
Second set were 12mm ones again from Warco, at this stage I gave up trying to order the 10mm set from them!!. These are much better if only because they are larger but a bit to big for my WM180 but I still use for heavy material removal.
No it's better to have a couple of useful tools than a selection box of crap. My mates lathe came with a boring bar from a company called Glanze which after a search I found at Chronos. These while are more expensive they should last a life time. I would class them as upper semi pro quality.
Index tips seem expensive but last quite a while. You usually only use two sides ( of a 4 sides tip) but there are other shapes of bars that allow you to use the other 2 sides. Shop around.
I hope this helps - I'm not biased but - YOU GET WHAT YOU PAY FOR - Nick
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I found this site that shows the different shapes of index bits
http://www.greenwood-tools.co.uk/ishop/728/shopscr6.html
BTW - I still finish my work with a pass using HSS with a gentle rounded edge, I only use the tips for metal removal especially when I need to take a heavy cut.
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Scrim wrote:

I sorta-agree with that.
But, do you want indexable carbide tools, or HSS?
I'd start with HSS, and learn to sharpen them. It's not hard to learn, a good teacher can show you how in twenty minutes, and you'll learn a whole lot about cutting metal that way - and that's what a lathe or mill does, they cut metal. With metal knives.
Once you can make a knife blade which will cut steel from a lump of HSS you will understand the cutting action a whole lot better than you ever will if you can't.
Also, you won't break as many HSS tools in the early part of the learning curve as you will break carbide tools, and they are cheaper to replace - mostly you can just regrind them.
And there are some jobs which are simply better done with HSS. It's sharper than carbide and less brittle, and for interrupted cuts and the very best finishes HSS wins hands down.
In fact, if you aren't working in hard alloys and can put up with the frequent sharpening needed, almost everything in the small lathe / model engineering field is better done with freshly-sharpened HSS than with carbide.
For the step up to carbide, brazed tools are perhaps a useful learning intermediary - you will break quite a lot of carbide while learning, and will suddenly find inserts stop being cheap .. And yes, you will break tools too, not just inserts.
However, as for indexable tools. Initially you want a 10mm square SCLCR right-hand turning and facing tool, a parting tool, and maybe a boring bar. That's it for starters, but - you are right, once you know how to use them without breaking them you do want quality tools here. These are expensive, sometimes very expensive.
Don't buy cheap indexable tools to learn on, they are a waste of money - use brazed tools for learning about carbide.
The Q-cut parting tool has a good reputation.
Greenwood are supposed to be the bee's knees for indexable tools for the small lathe and mill, but I haven't tried them, unfortunately they are too expensive for me. About £150 for the three tools and some spare inserts. http://www.greenwood-tools.co.uk /
Glanze (from Chronos) are - well, okay, sort-of, and a fair bit cheaper, around £75. One thing though, the actual Glanze inserts aren't very good for small lathe work, if you can get inserts made from aluminium they work much better - most inserts are designed to last a long time in big rigid machines, and they are not sharp, the edges are rounded. This works okay in big machines, but not in small lathes.
Oh, on breaking tools - you _will_ break tools, and you *should* break tools, especially disposable ones like small drills, brazed carbide etc., while learning. If you don't push a tool until it breaks you won't ever really know what it can do.
Just try not to break the expensive ones!
-- Peter Fairbrother

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Mostly agree with what Peter said, but I'm pretty sure he meant to say "made *for* aluminium", i.e. for cutting Al alloys, not "made from aluminium" (wouldn't last very long). The "for AL" tips are sharper than the ones for steel, so they are better suited to the dainty little cuts we home engineers tend to use; the ones for steel have a less sharp edge and are for hogging cuts our lathes are mostly not rigid enough to tolerate.
David
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Scrim wrote:

Quote from Dave Baker: -
http://www.rcgroups.com/forums/showthread.php?t †7972
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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Dave Osborne wrote:

I assume Dave Baker is exaggerating about regrinding HSS tooling every 5 minutes as that implies running the HSS at too high a cutting speed for the material. Learning to calculate cutting speeds is simple and important as too high a cutting speed for the material will kill carbide as well, although the speeds are higher. I guess if you never think that you'll need a custom ground tool then maybe you can buy off the shelf insert tools and not learn the basics of grinding them yourself, I often need oddballs and either grind my own in HSS or sometimes carbide, I have acquired quite a selection of ones over the years which now fill most requirements. I think that learning to grind the basic tools is useful, certainly the first thing I had to pass in a proper machining class, once the basics are learned then the choice to use HSS or carbide may be better judged and the results each gives on the machine in question can be judged as well.
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A word of warning when buying tools for the Mini lathe. If the standard 4 slot fixed tool holder supplied with it is the same as the one that came with my nearly 11 year old one then the distance between the base of the slot that the tool goes in and the centre height of the lathe is just a little over 8mm. So it would seem that the largest lathe tool to fit that holder will have an 8x8mm shank but check if buying an indexable tool that the replaceable insert doesn't sit slightly above this as it will then be above centre height. You can correct a small difference by jacking up the back of the tool with a bit of shim* so the tool points down at a slight angle but this will affect the clearance angle.
The smaller 6x6mm shanked tools will work provided you put shim* under the tool to bring it to height but the tool will not be as rigid as the 8mm one.
A set of "8mm" tooling was supplied with my lathe, however the braised on carbide tip brought the height up to over 9mm which made it frustrating to have to wait until I could solve the problem before I could have a good play with my new toy! - I tried using the vertical slide (which I ordered with the lathe) to mill off the excess but this only resulted, though my inexperience and clumsiness, with a damaged brass feed nut - happily Chester sent me a replacement free of charge the next day.
Luckily there was another model engineering show a week or so later where I was able to measure the tooling and got a cheap Chinese set of "8mm" indexable tools where the tips were at 8mm. I am still using those same tools although now with more up-market tips nearly 11 years later.
I also bought the cheapest "quick change" tool post I could find (the hole needed to be opened out to fit the lathe) which of course solved the problem of the tooling being too big as it's easy to set to the centre height but as the tool is now offset there is less rigidity.
The next problem with tooling was a parting off tool. Rigidity is all important and I quickly found it was essential to clamp the saddle to the bed, initially with toolmakers clamps, and then a purpose made clamp (over the years the design of saddle has varied so my clamp won't work on modern mini lathes but a number of suitable designs can be found on the internet)- You can improve the rigidity a bit just by applying the handle of the leadscrew nut thus clamping the saddle to the feed screw provided the feed is disengaged. I didn't really solve the problem of parting off until I bought one of the parting off tools with a replaceable carbide tip from JB cutting tools it actually fits without shims. Some people find the use of a rear toolpost with the parting off tool upside down the answer to parting off easily, but although I tried making an attachment to do this there really isn't enough room on the mini-lathe, however as the chuck is bolted on and thus cannot come unscrewed and the lathe will run in reverse there is no reason why you cannot put the parting off tool upside down in the normal position and run the machine backwards to get the same effect - of course making sure that the tip is at centre height.
With regard to sharpening, I always keep the tips of HSS and, when necessary, carbide tools sharp by using a couple of strokes with a diamond mini stone between cuts which aleviates the need to remove the tool and resharpen on the grinding wheel. The one I use came from Arc Euro - the orange handled fine one 070-030-00850 or is in the 4 piece set 070-030-00880. I noticed that the local pound shop had rather more chunky versions which would do. As long as you follow the original profile of the tool it's a quick and easy way to keep a tool sharp.
* a cheap source of soft aluminium to use as shim (and to protect work from marking by the hard chuck jaws) is from individual trays of cat or dog food - if you don't have a cat or dog your local neighbourhood fox will be well pleased to receive the contents on a cold winter night.
Sorry to go on but I've had a lot of pleasure from my mini lathe for nearly 11 years and hope that you get as much from yours.
Ps a book I would have found very useful if it had been available when I got my lathe is Workshop Practice Series No.43 - The Mini-lathe by David Fenner which he based on a series of articles he wrote for Model Engineer's Workshop magazine. I also got a lot of help from the various mini-lathe Yahoo groups.
Best wishes Alan
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wrote:

Talking to my old mentor on the way to Harrogate, (Being a novice) I said that I was struggling to make any sense of the brazed carbide tip tools for my lathe. His response was "you're learning then..."
I've had no trouble at all with the indexable cheapo chinese sets, except that the holding down screws sometimes appear to be made from toffee.
Steve
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Many many thanks for all the advice! There's no such thing as 'going on' to much as far as I'm concerned! It's all gold dust to me :-) I can see there are two distinct schools of though on this topic, divided by Carbide and HSS. I don't have a bench grinder or anyone to teach me lathe tool sharpening. Carbide inserts intended for Aluminium sound good for my purposes, but I'll look at HSS if I have problems getting a good finish on metal, and perhaps for extra sharp home made tools for turning acrylic and PTFE. I'm surprised indexible tools are so expensive - is it justified, or are the manufacturers running a cartel! I might risk cheap indexables and replace the screws. Chas, where do you get your £2.50 inserts? Are they the sharper type for aluminium? I'm unsure what size tools I'll need. My Lathe is due on Wednesday (!!!) so I guess I'll wait and measure up then, or decide to replace the 4 sided tool post provided. The Glanze site shows handy diagrams of what they reckon each tool type is for by the way: http://www.glanze.com/indexable-tool-holders/turing-tool.html Parting off will need special attention. I can't find a 'J.B. Cutting Tools' web site. Are they online? I've got a nice selection of cheap diamond grit sharpening tools. They don't make much impact on carbide that I've noticed though! I happen to have some 0.5mm thick mirror finished rings from a scrap yard that appears to be Tungsten Carbide judging by the density (about 15.8 g·cm-3). It breaks like glass when severely bent, but I'd like to try at making my own parting tool using it at some stage. Again, many thanks for all the advice,
Scrim
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Scrim wrote:

The tools used may divide by HSS/carbide, and some people only use one or the other - but for most hobby people purposes both HSS and carbide have their uses. Don't be fooled by the purists, try both.
You may have noted, as an aside, that the HSS purists tend to do small precise stuff, while the carbide purists tend to do large or high-volume stuff.
That's probably because, for most purposes, HSS is best for small precise stuff, while carbide is best for large or high-volume stuff.

A bench grinder is cheap enough, but someone to teach is maybe harder - it's not that there's a lot to learn, but that it's very hard to teach it in writing, and very easy in person. Takes considerably less than an hour in person, but in writing ...
I tried to write a basic HSS right hand turning and facing tool hand grinding introduction, and came up with "hold _this_ edge of the HSS toolbit against the wheel".
Even before that it got tricky, hold it wrong and it can injure you. If you hold it like _that_ it will hurt - but if you hold it like _tother_ it won't hurt, and if you hold it like _mether_ it will be nice and controllable.
But describing what's meant by _this_, _that_ and _tother_ in words is hard.
Then it's: grind _that_ bit so you see a flat. See it?
Grind it some more, until it gets really hot and then goes blue - you have now ground it too much, the temper of the HSS is lost. Don't worry though, you just have to grind it some more so the bit with the lost temper is gone.
So, to grind quickly the idea is to dip the HSS in the water to cool it before it turns blue - but if it goes "hisss" when dipped, then it doesn't like it either, and may microcrack from the shock of meeting the cold water; so dip it before it hisses, and before your fingers get too hot either!
Practice that a bit, so you know when it's going to hissss - in future, if it gets that hot but it's perfectly the shape you want, then just leave it to cool. If it hasn't gone blue then it's still tempered enough for at least some cutting.
Now, grind the HSS so the flat covers the entire side of the HSS, and is at angle X. Oh, and _tether_ angle should be straight.
Now, is the flat really at angle X? The angles used don't usually have to be that accurate. If it's _this_ much out that's okay, if it's _that_ much out then it needs regrinding. Actually that's just grinding some more, at a better angle, not "regrinding", whatever that means.
Now we grind the second flat, which is much the same as the first. It's like _this_ and _that_. The angle is Y, and straight.
Now grind the third flat, which again is similar. The angle is Z _this_ way and X again _that_ way.
To sharpen, just grind the third flat again.
Many people smooth the sharp point out using a stone or diamond flat. A few strokes like _this_ and _that_ will do it. You don't want to smooth the cutting edge!
Well that's about how hard it is to learn to grind and sharpen HSS tools. It's about all you need to know to start, and most of the rest is just looking up angles and designs.
Describing it properly in words, without the _this's_,_that's_ and _tother's_ though - well it ain't easy, is all I'll say.
Carbide inserts intended for Aluminium sound good for my

In a bit I intend to offer people here a starter set of carbide tools - I used to be a HSS purist, but am now converting to the middle road. Should be about £25 for a 10mm sclcr turning and facing tool, plus a boring tool, plus six inserts.
It's a starter set - it won't last forever. It's not made from cheese, but it isn't what-snap-on-use either. Intended for HSS people to get used to carbide, and break three or four inserts while learning to use them.

I don't know if it's justified - can't afford the expensive stuff to try. But I've broken too many "cheap" indexable tools to think them cheap overall.

Got a spare one you could send me?
-- Peter Fairbrother
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Peter Fairbrother wrote:

aluminium-type (Kennametal)
inserts.

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Peter: I'll see if I can get some more, but if not I could snap a piece off one for you as I managed to 'open' a ring without shattering the whole thing recently They're flat rings, presumably cut from a sheet 0.5mm thick, outside diameter ~13cm, inside diameter ~10cm. They were something special, but the only idea I've had is they may have been the wear surface of a thrust bearing. I'll try contacting you through the email address you post with for your address details.
Scrim
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On 26/10/2010 22:08, Peter Fairbrother wrote:

There's a series of 4 vids by Tubal Cain on Youtube which might help Scrim. The first one is here

http://www.youtube.com/watch?v=hrDr4rYLiAk

As a newbie myself, I feel he doesn't describe very clearly the "holding the end rotated a bit" technique (to get the side clearance angles), although he does mention the clearance angle is 10-12 deg (I thought it was supposed to be 7, which shows it isn't critical). If you don't hold it rotated you'll soon see that the ground area forms a vertical line with the unground part, instead of the sloping line shown at 3:56 into the vid, and you grind the whole side face of the new blank instead of working from the bottom up to the top. But this is nit picking and your perception of his demo may be different to mine.
If you prefer words, I found
http://www.sherline.com/grinding.htm
helped me when I was starting out. OK, I confess I had a mentor, but his role was mainly to slap me every time I whined that it was all too hard, 'cos it's not: sharpening a lathe tool is one of the easier skills to learn.
Alan
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Does this apply to industrial users too ? Or do they have another solution for small, precise stuff (that won't fit on a grinder) ?
-adrian
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Adrian Godwin wrote:

I imagine they have many other solutions which are not available to the small workshop, but I'm not an expert on this subject. I'd like to know more, if anyone is.
They can afford to pay big money for big iron, and places to put it, after all - and it's much easier to do small stuff on a big lathe than big stuff on a small one.
-- Peter Fairbrother
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wrote:

Bear in mind that the difference between the old tool steel bits and HSS bits is that, whilst tool steel looses its temper at not much more than 150C, HSS can still cut when its glowing a dull red. OK, it doesn't last very long under that treatment, but HSS can still shift a lot of metal when it needs to.
Mark Rand RTFM
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Adrian Godwin wrote:

Regarding small precise stuff I got a whole selection of HSS turning tools and probably a lifetimes selection of slitting saws and side and face cutters, including custom grinds, out of Horstmann in Bath when they flattened the factory in Weston. IIRC that site made the clockwork central heating timers and the like so lots of precision small parts, much in brass IIRC. That site is now housing as I expect the product produced there was obsolete and the property worth more for development, the modern production moving to Bristol AFAIK and now electronic.
Many of the HSS turning tools seemed to have been ground for a specific job and many have proved very useful for the variety of things I do.
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Thanks folks. I'm definitely going to get some HSS tools too. Do they do Cobalt versions as with drills by the way? What about this for a plan: I get a set of pre-made HSS tools so I can use the original form as a guide during sharpening and hopefully get away with using just diamond coated hand sharpening tools. A combination of that and using the earlier links to video and texts on the subject should add up to a decent introduction.
Scrim
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