Silly Tool Question (absolute beginner!)...

Size of tool is governed by the distance from where the bottom of the tool rests on the toolholder and the center height of the lathe, its easier to pack up a tool than try to make it lower. Your existing tools are probably 3/8" and with grinding the cutting edge is probably a little less than this. I don't have a Myford so can't give you the max tool size but it may vary depending on your tool holder.
The indexable bits all have a very small radius on the corners which will help with your finish and the "rhombus" shape will typically give 5degree of clearance which will also be better than a pointed tool.
Personally I prefer brazed carbide tools for a fine finish as the insert type are designed for higher stock removal rates and lots more cutting fluid than a hobby turner is likely to use. For the price of a couple of insert tools you could get a large selection of carbide tools, grinder and green grit wheel, you will always need to frind specials for particular jobs anyway. They are handy for getting through the skin of castings and I like the boring bars especially the 6mm shank one that gets into small holes.
Jason

One thing you must get right is the type of insert. Most carbide inserts are designed for high volume production on sturdy machines. They can power inserts with rounded cutting edges into steel with brute force and rigidity and still achieve a good finish. For home shop lathes you want non-ferrous inserts even for machining steel because they have razor sharp cutting edges which cut without the application of lots of force. Such edges wouldn't remove stock for long on a 5 ton CNC lathe taking 4mm deep cuts with 15 bhp but they're ideal for tickling a few thou off on a Student or Myford. Usually such inserts will be uncoated and silver or gray in colour. The black and gold coated ferrous inserts will have much less sharp edges and are only useful for roughing work which we don't tend to do.
Also, by 'rounded cutting edges' I don't mean the tip radius which is a separate factor. I mean the sharpness of the cutting lip. The tip radius on most of my turning inserts is 0.8mm which is quite large but of minor significance compared to how sharp the cutting lip is.
So always ask for inserts for machining aluminium even if you want to turn steel. A salesman will start off by asking you the material and then try and sell you an insert totally unsuitable for your use. An insert 'designed' for high volume steel turning on a sturdy lathe will just skate over the work on a Myford and leave a finish like a ploughed field. With a new sharp non-ferrous insert I can take dust cuts on the stringiest steel on my shagged out old Student and still get a finish you can see your face in.
Start off by measuring the height from the centreline of your lathe to the bottom of the tool holder register. Then buy the largest tool which will fit that and not ride above centre height. Obviously adjustable tool holders make life much easier than fixed ones where you have to shim the tool up. Then look at the cost of inserts which varies hugely and go for a holder which takes cheaper inserts in preference to one which costs less to start with but requires expensive inserts. Square and triangular inserts tend to be good value because they give you 8 or 6 corners per insert. Diamond and rhomboid inserts only give you 4.
When facing off material never go beyond the centreline of the bar. You'll crack the edge off your insert every time as the cutting action changes from down to up. If necessary stop a bit short and leave a pip and then file that off rather than screw an insert.
I think that's it for my stock of pearls of wisdom for one day.

In article , Dave Baker writes I have used lots of inserts (mostly Stellram) for cutting steel with very good results. 8 corners??? To do this, a square insert must presumably be able to work upside down; never sen any like that, maybe I'm using the wrong sort Been using them for years, never been careful to stop at the centreline, and never had a tip break under those circumstances (broken plenty in other ways, usually by being careless and digging in). Perhaps this is because I tend to take light facing cuts, rarely more than 20 thou. I can see that the tool cutting edge would be weaker if it was working backwards (just like reamers, which should never be turned backwards). However, if the tool is accurately set to centre height, there is nothing there to press the cutting edge backwards once you pass the centre.
David

In article , David Littlewood writes Should have said "inserts designed for cutting steel, for that purpose"
David.

Are you a member of a club, if so have a talk to some of the members. If not join a club, most members have a lot of experience. This is not a dig at you. I wish when asking for help about operating machine's they would give some idea were the are in the country. I have always said if a new model engineer needed a bit of help and it is not to far from North Lincs I would willingly give them a morning or afternoon in the workshop. FREE. A cup of coffee would be acceptable. I have spent 40 years working in machine shops and turned or milled most things.

Garth Hi
Never worry about asking what you call elementary questions we all started there and were given the help we needed, although as an apprentice it invariably came with a very large helping of ribbing. The problem is when you have been turning for some time it becomes "second nature" and you can forget to mention some of the gems learnt early on. Communication can be difficult and it's easy to see why those who can communicate effectively with the written word are held in high regard. As David mentioned on another post George Thomas with his book The Model Engineers Workshop Manual is well worth reading. I also agree with Bill a couple of hours "face to face" over a coffee with the lathe in use is worth many pages of reading.
It becomes difficult when explaining a comment or piece of advice to know how far to go to explain "why". As advised you can indeed get 8 cutting edges on a square insert and each with large radius nose but, (you knew that was coming), on some the edge's of the tip are square to the top and bottom surfaces and the tool, to get cutting clearance is presented to the work with a negative rake angle. I have seen others which are "wasted" in the thickness to produce cutting clearance but they are (were?) relatively thick to avoid rubbing and were only really suitable for small diameter work, again to avoid the lower upside down edge from rubbing. To be honest I only saw these inserts when a tooling rep was trying to sell them and for us they were not successful so I don't know if they were ever in general use. Negative rake cutting has advantages and works fine when you have a large very rigid machine with lots of horse power. With our lightweight machines a positive rake cutting edge is essential. The same power/rigidity issue exists with the nose radius; the larger that is the greater the contact area between tool and work and the more rigid the machine needs to be to avoid chatter.
Here it gets confusing again as with HSS you can get the tool very sharp and reduce the speed so that a HSS tool with large nose radius (or a form tool) can cut well on our machines. Inserts only work well at relatively high speed and when working hard with a minimum depth of cut of say .004", so reducing the speed and depth of cut to avoid chatter takes the insert well outside its operating range. Keeping speed up can induce chatter which instantly chips the tip and renders it useless. Therefore we need to find the right compromise for successful cutting in our situation. You have mentioned taking a cut of .001" off a bar and that is not an ideal way for an insert tool to work well, in fact most inserts when they have been used for a while will not cut at all with only .001" cut they will merely rub. One other strange thing about most inserts is that they produce a better finish when they have been used, with new edges producing a slightly ragged finish. This is to do with the "sharpness" of the cutting edge where a (minutely) blunt edge will burnish the material and produce a better finish. Don't be under any false illusion, on our machines tipped tooling when used correctly can produce superb finishes but it is a different technique from that used with HSS.
The set you have identified is fine, Glanze are good mid-range tools and will last well. My only concern is if you really want to start with a set that expensive before you have confirmed that you are happy with insert tooling. I have several sets, Warco do one that is a fair bit cheaper (=A345 ish) although it uses a variety of tips rather than the one CCMT type that the Chronos set uses. Some of the tools included with these sets never see the light of day. I have always recommended that a good start is to buy a SCLCR Right Hand tool in 10mm square for a Myford. This =A315 will let you try to see if the indexible system is right for you. The tips are CCMT and have a small tip radius and are capable of providing a good finish when either turning or facing. As I mentioned above they work best with a fairly high speed and with a reasonable feed/DOC. One of these is in the set you mention and this is the one you will use the most. I tend to use uncoated CCMT-06-02-04 tips from Widea (RDG currently) and they are a good compromise for steel between metal removal/finish/life on my Myford S7. The coated type (gold coloured) do not work quite so well for me and I use them more for heavier work. As I metioned before I have had excellent results from the TPUN type as well.
Garth I'll leave it there as the post is getting very long but you can see cutting tools are a "science" in themselves and we could go on and get more and more confusing. When I've exhausted my little bit of knowledge no doubt someone else will come in with more scientifically based answers that get further and further away from the actual cutting experience. Garth I suspect that this will ask as many questions as it provides answers but there is much to consider and the best way to learn is to "play" a little and see what works for you. In my experience there is no "ideal" set of cutting tools of any type currently on the market. Most people using small lathes seem to end up using a mixture of HSS and tipped tooling. I agree with Bill, if you let us know what part of the country you are in, someone may be willing to spend a couple of hours with you for the price of a couple of cups of coffee or in my case tea as I can't stand the stuff.
Best regards
Keith

I think that whilst Keith is probably right on the ball, it is time to simplify the reply to say to Garth, 'Look Chum, you bought a design which came out in 1948' As such hundreds of thousands of users have used HSS and carbon steel tools on them in those years- and will continue to do so. You may have a problem, Garth, but had you taken on board the comments of Charles Ping and later, my own self, you would have read up the works of Sparey, who drew out formats for lathe tools, you would have read up Ian Bradley who wrote up on three of the Myfords and as an encore, wrote up a complete book on merely doing lathe and shaper tools. OK, Bradley did touch on carbide but not on 'inserts'. Thomas, who was one of the most expert workers on Myford lathes- and whom I recommended- criticised the need for carbides as being unnecessary save for ropey castings which should have gone back! Thomas went on to describe the use of 'hardened nails and having had Myfords for yonks, carbide is not a substitute for the inability to correctly sharpen a lathe tool and to set one up correctly to cut to 'exhibition standard'.
The information is there but if you wish to have a time breaking expensive carbide tips in your learning pattern, press on- regardless. The suggested books are by no means the sole information but I would suggest that you go to Chronos or wherever, and buy distilled wisdom- which will outlast your present ideas.
No charge for my tips, sharp though they may be.
Norman Atkinson

Norman,
Thanks for the comments - always appreciated.
Far from not heeding your advice, I am simply trying to analyse all th differing bits of wisdom I am getting, in order to get some toolin which will a) be fairly inexpensive and b) actually give me some tim on the lathe in order that at some point I can make my own decisions.
The fact is that I have three of the suggested amateur lathe an machining books on order from Amazon which have not arrived yet. Thi is part of the reason that I am asking for advice here, which - as yo say - will almost certainly be contained within the books. I can't ge them here any quicker unfortunately, and they have been on order fo two weeks now. I am just keen to make a start.
I do read all responses to my questions. I also appreciate the dept and quality of the experience of those who have taken the time t respond. Remember though, that at some time in the distant past, eve you were once a 'beginner' ! So please be patient.
Regards,
Garth.
ps. I haven't actually bought any tooling whatsoever yet, just use what was with the machine when I bought it
-- DR_ ----------------------------------------------------------------------- DR_G's Profile: this thread:

In article , ravensworth2674 writes I think you should lighten up a bit, Norman. We were all beginners once, everyone benefits from a bit of sound advice when starting out; I don't think there is any reason to get tetchy.
Garth,
As someone who was in your position once, i.e. absolute beginner, no metalwork teaching at school, etc. etc. I know how it feels. The following is my opinion, based on my experience of 25 years of home engineering with no tuition or professional experience, using a Myford S7 and a modest size milling machine (FB2).
Norman refers to several books by highly respected authors. However, many of them were written 50 years or more ago, and some things have moved on since then; also, there is often room for different views, even among contemporary commentators.
I started out with a miscellaneous collection of HSS tools, some new and quite good, some decidedly dodgy, a bench grinder with only a plain tool rest, and some sharpening stones. I learned to grind fairly simple knife, facing and threading tools, and to hone them, but frankly it was all hard work and a bit hit-and-miss for me. When I discovered replaceable tip tools it was like my enjoyment of the hobby was doubled. Sure, the tools and tips are not cheap, but (a) I've mostly been in the position that my time was in shorter supply than the modest amounts of cash involved, (b) top quality HSS tool blanks are not cheap themselves, and (c) I concluded that the only way for a home user to get good results every time is to buy or make a proper tool grinder, the cost of which will buy a *lot* of replaceable tips. Time-served master craftsmen can probably do this sort of thing freehand, but the hobbyist will have a lot more trouble.
Sure, there are debates about whether a replaceable tip of some particular design is "ideal" for our purposes on a fairly light lathe with modest cuts. All I can say is that after using them for 20 years I have found them fine, I can take a few tenths off FCMS with no trouble and get good finishes. Maybe I could get an even better finish with a polishes HSS tool (and I do have many of those) but frankly a couple of minutes work with a No 6 cut Grobet Swiss file well soaked in cutting oil puts both to shame if finish is what you are after (and when you see the price of those, you will think carbide tips are dirt cheap).
I do plan to buy (or make) a fairly high performance tool cutter sometime soon; however this is not to turn out plain vanilla turning tools, but to sharpen milling cutters and the like (of which I have a drawerful requiring attention) and to make cutters I cannot buy.
However, that is one strand of opinion, you have heard others here, and some from people who have lots of experience and knowledge. It maybe that some replaceable tip tools are better for our purposes than others, it may be that the others' experience is too much oriented at heavy production-level cuts, it may be that I have been doing second rate work or have more money than sense. As usual with usenet, you will have to read all the answers, pick the ones that you think suit *your* case the best, and do some trials of those chosen paths to see if they suit you.
Happy cutting,
David

.....and I think you'll have to go a long way to find better advice than that offered by Keith, Norman and Bill. I endorse everything they say - do take their advice and then you can at least come back for more without the risk of pissing people off.
--
Chris Edwards (in deepest Dorset) "....there *must* be an easier way!"

Sadly I am now too old to be included in 'the Grumpy Old Men'. I mentioned 1948 conscious of the possible backlash. Then, young men were given all of 6 weeks to master the skills of keeping aeroplanes in the air.Oh, yes, keeping the Boss man's favourite Griffon Spitfire in the air fell to a young man who unashamedly admitted that he had not the education from those uncertain days of bombed out London. The years moved on and 'Johnnie' got his pension for the terrible injuries which he sustained from those days. He asked me why I had become involved. The answer was a simple one. Johnnie had also strapped me in the back seat of other aircraft and with only a fragmentary training had ensured that I came back each time. Of course, the Boss's old Spit is still airworthy though in San Diego. Somebody flogged the other old girl which had gravitated to being the hack of the Battle of Britain Memorial Flight and she took off from 'John Lennon' after another engine change. Two more of the old girls are at RAF Cosford keeping company with two of our Antarctic Austers. Naturally, I always drew the short straw- I never even got the 6 weeks training. His Easter greeting card rests on my mantlepiece as a sort of thank you for 'insuring the last bit of his old age. Blame Johnnie, if you must.One can learn a lot from a sprog engine basher! But you have to listen!
Norm

When I discovered There seems to be a body of opinion among certain model makers that HSS is the "proper" way to do things and that carbide is cheating or maybe replacing tool sharpening skills that took a long time to acquire. All I can say is that anyone who makes a living from their machines doesn't bugger about with HSS anymore and hasn't done so for many years. A non-ferrous carbide insert is as sharp as you need to machine anything I've ever come across. Maybe you can get an even keener edge on steel, a razor edge so to speak, but that's not what you need for machining metal anyway. Wood perhaps, or if you want a shave between jobs but an edge like that is only going to last seconds on metal anyway.
As can I. The idea that carbide inserts only work when taking cuts of several thou as mentioned in a previous post is pure nonsense. Even the pros have to creep up on a size a few tenths at a time sometimes and if you could only take cuts of a certain minimum depth with carbide you'd be stuffed when you got any closer to target than that.
As I said in my original post, the trick is having the right inserts and for our occasional and light machine use that means as sharp an edge as possible so either non-ferrous inserts or finishing inserts for steel but I still don't find those as good. The only time I'll use a ferrous insert is when I'm hogging a lot of metal off steel and don't want to risk damaging the edge on a nice new sharp non-ferrous insert until I have to.
I've tried brazed tip tooling, as have we all no doubt, and I still use it occasionally, for parting off mainly, but out of choice I'll always use a carbide insert when I can. I'd also say that you can't beat having a diamond wheel if you need to sharpen brazed tips. Green grit wheels are a dismal second best and one of the best things I ever bought was a cheap Chinese diamond cup wheel from Cronos which I mounted on an arbour and use on my mill. It's taken many mm off dozens of milling inserts I use for valve seat cutting and hasn't worn at all.
Anyway, each to their own I guess but if I need to mill 2mm off a cast iron engine block or a big flywheel the last thing I need is an HSS tool which will need resharpening half a dozen times during the job. I want to stick a tool with a carbide insert on the job which will take most of the metal off in one pass, the rest in a finishing cut and still be sharp enough to do another 5 similar jobs before it needs replacing.
The world has moved on since the books mentioned previously were written. I don't use an open fire and a skewer for cooking my evening meal, I stick it in a microwave oven for a few minutes, I don't cut the lawn with a scythe, I push a petrol engined mower around for half the time and it collects the clippings while it's working. I don't use HSS steel for machining if I can avoid it, I use carbide inserts which last ten times as long and remove metal five times as fast. Maybe 'proper' engineers can sharpen an HSS tool to the ideal edge on a grinding wheel or reface a drill bit to exactly 118 degrees by eye. I can't do either of those things but I can fit a new drill bit which only cost a quid anyway in a fraction of the time and get back on with the job.
I think it boils down to this. Do you want to become highly skilled at refurbishing shagged out bits of HSS or do you actually want to spend your time cutting metal? If the latter then buy some carbide insert tooling and enjoy your hobby.
I can also forsee this debate moving on in 20 years to the 'old timers' who think carbide inserts are the only 'proper' way to machine anything and newcomers who use PCD (polycrystalline diamond) and CBN (cubic boron nitride) to do things five times as fast again.

Dave,
OK, so I will now once again forget the HSS tools (as I had don previous to reading Norman's recent advice), and return, somewha wearily, to my 10mm Glanze Mini Indexable Turning Tools. Simpl question - are the inserts supplied with these suitable for the kind o speeds and depths of cut that the ML7 is capable of?
Regards,
Garth
-- DR_ ----------------------------------------------------------------------- DR_G's Profile: this thread:

Oh, dear! Did no one 'do' history at school? Since 1948, things have changed but never quite repeating itself. As far as Garth is concerned, he can now have the choice of lathe and other tooling at what is give away prices because with a bit of lateral thinking what cost many thousands of pounds then, is available for perhaps a =A3100 now. It translates into a couple of tanks of fuel for the motor car.Moving off further, this works out at less and perhaps only a third of the price of the materials to make up a home tool and cutter grinder for which there is the long term need to actually construct. I've done it on a Quorn and and I have done it on a Stent and I nearly did another Quorn and hastily flogged the plans and castings etc for a locally available Clarkson Mark one which probably came out of the Ark but resided in a barn.The pedestal was too heavy to remove but the rest of it is OK. My luck doesn't take in all the bells and whistles but these came later. It is surprising just how effective B&Q 50mm PAR timber makes tool holders if fastened down with Wilkinsons best bolts! Of course this is for HSS stuff- well? Today, rising to the challenges, diamond wheels and CBN things fit which is more than I can say about my incontinence pads! So are we finished? Nah, let's go for double top! Today, or was it yesterday,? I got a set of 10 diamond pastes of bewildering grades for a modest =A320 note.
True, I haven't really been able to get my head around low speed pulleys to hone- err, carbide tooling on the beast.
Now where did I put my Zimmer frame? Bugger, fell over it as usual.
Pity about the 6 week course but I did get the offer of a scale Tornado Bomber 14 foot long- for free. So has anyone got a helicopter which was originally used to do drop tests? It was the Royal Air Force who offered it!
Gurthcha!
Norm

In article , DR_G writes Garth,
You will still need to use HSS tools when you want to make something you can't buy, but probably quite rarely.
I have never used the Glanze tools, but all the accounts of others suggest they will be fine. I have used Stellram tools for many years with considerable satisfaction, and recently acquired a couple from Greenwood (which IIRC originate from Sandvik).
Your best course is to suck it and see.
David

(Snipped lots of good stuff)
(snipped lot more good stuff)
And surprisingly as the author of some of the "previous nonsense", so can I, and I do as a matter of course day to day. The advice was not meant for someone who has years of experience and has gained the confidence to select an appropriate tip type, wear state, speed, feed, coolant (if any); whilst putting the tool in the required position within a couple of tenths by fully understanding how their machine works and where it is worn and even with some of the old crap I've used where to lean at the appropriate time. The advice was to help a guy working on his own with an old lightweight lathe, not looking to earn his living, and with no previous experience. I stand by the original comment that in this context HSS is easier to use particulary for steel finishing. Of course you can use carbide to remove minute amounts of material but it is not just a case of fitting one of the easily available "general purpose" steel cutting tips and winding the cross slide dial until it reads two tenths more than before, risking a higher speed of 350 rpm and pouring oil all over it. I don't mind being rubbished it is a way of learning but if you are going to do so at least keep the context similar.
I fully agree that once you have gained some confidence and a working knowledge of the machine you are using most people with a Myford will be comfortable with modern positive rake tipped tooling. Unless you deal regularly with people who are starting out from scratch it can be difficult to understand why they are at all reluctant to ignore all the "manufacturers tables and previously published charts" of appropriate tool tips and use a non ferrous one, but they are. Dave, whilst I have sufficient experience to see the merit in your advice, a surprising number of people in this position are looking to reduce the risk of their own mistakes and feel they must stick rigidly to the "recommended" techniques. With confidence and experience it soon becomes obvious that there are many ways of "skinning the cat" and most work reasonably well, the trick is to keep experimenting while retaining the solid known base of what works to fall back on if the change is not totally successful. I suppose this is the reason I have a couple of boxes full of tips and holders that might one day see the light of day but equally might see E-bay, no doubt they will work for somebody.
The one other issue is that for someone embarking on a hopefully long and enjoyable "hobby" they will at some time need to use a form tool of one sort or another. Here HSS is almost essential as it can be easily shaped and sharpened. Also, sadly in these days of obvious oppulence in some quarters, in later years not everyone is able to replace a =A31 drill everytime it just needs to be sharpened. For many of us in later life, time becomes cheaper and tools more expensive. If you are going to meet HSS at some time you might just as well make it part of the learning experience at the start.
Sorry for still taking the opposite view in the context of the OP question, but there we are one of the advantages of these forum is that many differing views are available. As has been said before read it, consider it, remember what it cost and .............. try it. The most effective learning method in my experience is to stick a piece of metal in the chuck, stick some sort of tool in the toolpost and switch on the machine and make chips.
Best regards, hope you have all had a better day than I have, took someones advice on a chain saw - now why on earth did I do that?
Keith

I have a set and am happy with the results I get in my 15 year old ML7R.
CCMT tips are easily available from a number of suppliers.
Personally if using the standard toolpost I go for 12mm shanks for rigidity, but I find the tips of some 10mm tools are a bit high for a quick change toolpost.

Garth
Yes they are, the one issue I might see is that for very small diameter work, if that is on the agenda, the top speed of the ML7 could be a little low for them to work at their best. These tools work fine for me on my S7 using FCMS.
Good original question Garth, you have managed to get some discussion going when it looked like the forum had gone to sleep a bit.
Regards
Keith

I'd definitely recommend starting with HSS tools and a cheap £10 grinder.
If you are set on carbide, get a few brazed tools and try them (or as someone else said, get a good RH indexable tipped carbide tool and four or more inserts - I normally say to get two of things that might break, just in case, but these _will_ break - and you will find it useful sometimes even if you don't end up using carbide by preference).
You need to get someone to show you how to grind HSS tools, preferably an old ex-apprentice - I don't think it's something you can learn from books, at least for the basics, though books may help later. That way you can quickly learn how to grind tools by hand - it took me about four days to get the hang of it, six months to get good at it - so I can grind tools which last - and it will take forever to get perfect :)
You'll begin to see how the cutting action works, without breaking expensive carbide tips. That's what it's all about, cutting metal with metal (or carbide, or..), and it just isn't obvious to the beginner, which I was three or so years ago. I had the idea then that you just moved the handwheels to the right numbers and the workpiece became the shape you wanted - but it doesn't work like that.
If the HSS breaks (it won't, but it might well get blunt quickly) you can just regrind. And please get some good quality HSS - you should be able to get half a dozen good 3/8 or 10 mm HSS blanks for something like £30. Sorry, but the Chinese/Indian HSS tool blanks just aren't good enough unless you are only swarfing aluminium.
Brazed carbide is not for me, but it is cheap and will give you an introduction to carbide, see if you like it - I wouldn't bother with green grit wheels though, use diamond - even the very cheap 20 mm dia diamond wheels in a Dremeloid are better than green grit.
Indexable carbide tipped tools (which are not really indexable if you want to change a tip and use the settings for the previous tip to eg turn to the same diameter with hundredth accuracy) have three great advantages, first you never have to sharpen them, second they cut faster when employed right and third you never have to sharpen them. They have two great disadvantages, first the tips are fragile, and second, you can't sharpen them.
Remember, cutting metal with metal (or..) is what it's _all_ about. If the cutting edge does what you want, that's all you need.
(I do a fair bit of work on hard-to-machine metals with CBN and diamond tipped tools)