lathe tools

I have a ml7 lathe and am about to buy a set of lathe tools and was wondering what view others have regarding the best type, HSS or Indexables

Reply to
bert
Loading thread data ...

Me too! I have a Colchester Bantam and would like to buy some TCT holders and bits.

I've seen the "Glanze" tools sold by Chronos:

formatting link
and wondered if these were any good. Opinions anyone?

Apologies for hi-jacking your thread, but which inserts would you need for free-cutting stainless and aluminium?

Reply to
Mr Crane

Don't throw your money away on pre-ground tools.

HSS definately. Get five or six 1/4" square HSS bits, and the same number of 3/16" HSS bits. Maybe Two or three 3/8" bits. They make good shims to raise up the others upon, to get them to center height, if you are using the Myford clamp type tool holder.

The 1/4" and 3/8" tools are slow to grind, but easy to see when so doing. TH esmaller bits are cheaper, and take far less time to grind, but are harder to see when grinding, so you have to have at least an idea of what you are trying to achieve. The small bits are plenty strong enough to do honest work on a Myford sized lathe.

Those will last you a VERY long time.

Get a decent small bench grinder, and learn to grind your own tools from scratch.

If you buy the pre-ground HSS tooling, you will have to learn how to grind them soon enough, and if you buy indexable, like as not, you will become annoyed with metalworking altogether, before you reach the point where the inserts start lasting long enough to seem worth the price.

Buy or download a copy of the South Bend Lathe book, How to Run a Lathe. It has some worthwhile info on tool shapes. Watch the angles, though. Try to avoid getting caught out, and grinding a tool that is supposed to be held in an upwards angles tool holder, if you do not have them (typically, like the ones made by Armstrong, they have a 15 degree upwards angle).

Cheers Trevor Jones

Reply to
Trevor Jones

Reply to
Bill

Depends mostly what you are working on. If it's mild steel, brass/bronze and ally then HSS is best for the hand lathe.

For stainless cobalt-HSS or carbide is a help, and for anything harder than stainless carbide (or even diamond, ceramic or CBN) is necessary.

HSS is sharper (when freshly sharpened) and much tougher than carbide - carbide is harder, but it is far more brittle. Carbide also works longer, harder and better at high temperature, but this doesn't matter much in hobby work - the brittleness of carbide is far more relevant.

I'd start with some HSS (or cobalt-HSS) blank square bars and a cheap grinder. Should cost about £30 in all, about the price of a single good indexable tool plus a few inserts. If you can get someone to show you how to grind HSS tools that's a big plus, but it isn't that hard to learn. You can then make almost any lathe tool you want, but some like parting tools and boring bars are better bought.

Many people like indexable carbide parting tools, even for softer metals, and there is some merit in this, perhaps because the cutting end is wider than the blade of the tool.

However after a bit of experiment and practice I'm getting good results with a HSS blade-type parting tool - sharpen frequently, mount rigidly so it's central on the crossslide and absolutely at right angles to the lathe bed, and lock the carriage and top slide.

The only time I use brazed carbide is for small boring bars. Regard them as disposable, but they aren't very expensive. Good for getting into smaller holes, as indexable boring bars need a large hole, and grinding boring bars from HSS blanks is very tiresome.

You might want to buy a cheap set of brazed carbide tools as an introduction to the brittleness of carbide - otherwise no. Another cheap-ish introduction to carbide is the TPUN RH tool available on ebay from marypoppinsbag - but throw away the horrible screw, make a suitable thick washer and use a proper M5 allen bolt instead.

But start with HSS, not carbide.

-- Peter Fairbrother

Reply to
Peter Fairbrother

A beginners thoughts:

Most here seem to say buy blanks and grind your own.

But, if you are a beginner isn't that just adding something else to learn and worry about? Is it not better for a beginner who already has a lathe to buy some ready to use tools so that they can get the hand of using the lathe first? Then later on learn to grind their own tools?

I mean, if you screw up the grinding you're never going to begin turning, right? Or the turning could be terrible with a rubbish home brew tool. You get down and potentially give up.

When I got my ML7, also got 1 tool, clearly ground by the previous owner. It worked ok, but I went out and got a set of cheapo tools to get the hang of the lathe. Then I started grinding up the cheapo tools to get the hang of grinding. Then lastly I bought some good blanks and now make my tools.

Its all very well old timers saying home brew is best, but for a beginner, that to me seems like a route to possibly not ever getting going. Or a recipe for added problems.

Beginners, and I still consider my self a beginner after 2 years of owning my ML7, need it simple.

So I say get some cheapish ready made tools, get the hang of the lathe, find the limitations, and then look at grinding your own tools a little later on ( or in parallel to learing about turning. That way you get to play at lathing immediately, with out the added pressure of grinding tools.

AC

Reply to
AC

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

formatting link

Reply to
Peter A Forbes

If you are a beginner, begin by learning how to grind tools. It is part of learning how the lathe cuts, and why it won't, at times.

If you never understand the basics of the physyics of cutting metal, you will never understand why you are not getting the results you wish to, or understand what has gone wrong (or right) with your set-up.

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!

Pity! You were stuck using one tool, and had no other options. Had you learned to grind your tools early on, you would have had ALL options open to you right away.

Gawd! You make it sound like getting three angles ground so they meet at a sharp edge, is some kind of bloody great miracle! It isn't!

If you had started out learning to grind a tool for yourself, right off, you would be a lot further along. You would not have run into whatever stunbling blocks that have held you back, and you would have a far greater skillset in hand, IMO.

Grinding tools is not pressure. It is a basic skill, that should require about as much concentration as learning to tie ones shoelaces. If you are getting scared by it, you are spending too much time considering the problems, and not enough time grinding tool blanks.

Really!

Easy!

Not Magic!

Not to be feared!

But if you never try it, you will never learn it!

Once you have this skill, all options are open.

Cheers Trevor Jones

Reply to
Trevor Jones

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.

Reply to
Cliff Coggin

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

Reply to
Steve

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

Reply to
Steve

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.

Reply to
Dave Baker

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:

formatting link
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:

formatting link
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

Reply to
Peter Neill

I was when I did and I agree whole heartedly with the overall tone of this thread. In general get HSS blanks and grind your own. I have a few indexables I keep for nasty jobs like stainless and getting below the skin on burned & rusty brake disks, but for 95% of normal daily use you can't wear out HSS fast enough to worry about - not playing about in your own shed, production work is a different kettle of fish altogether.

Richard

Reply to
Richard

This part I have seen before from various sources, hence heading back to HSS which does work for me

What you need for small lathes and

This part I haven't seen before - I'll have a hunt round and see if I can find some at resonable money.

Question is, why do the sets sold to folks with little lathes always come with steel grade inserts?

Steve

Reply to
Steve

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 =A35 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)

Reply to
jontom_1uk

Keith, sent you an e-mail. Much cheaper than £5 a pop

Peter

Reply to
Peter Neill

Peter - wouldn't mind the same pointer -

eMail is good

Steve

Reply to
Steve

from Richard

I was fortunate enough the get an apprenticeship with Coventry Gauge & Tool where preparing tools for lathe work came second only to general 'fitting' work.

Although I didn't touch a lathe between 1962 and 2005 I still retain all the skills I gained during the apprenticeship and sharpen all my tools by hand on a bench grinder - I really do mean _all_ my tools - today I converted a broken 1.4mm carbide drill to an end mill and made a 0.3mm wide carbide parting off tool from another damaged 0.5mm drill. 95% of my lathe tooling is HSS but I do have a few indexable carbide tips that I use as if they were HSS (as far as reginding/sharpening is concerned) these are used on 'difficult' materials such as Stainless Steel, Spring Steel and Cast Iron.

For me, each tool material has its particular merit and knowing which to use and when is the skill. Buying pre-ground tooling might be alright - and even necessary - in a producion environment but for 'hobby/home workshop' use it is imperative to cultivate the skills needed to keep all tools sharp - a blunt tool is a liability!

JG

JG

Reply to
JG

me too!

Alternatively, does anyone have any for-aluminium TPUN or TPMR 11030x /

22x inserts I could try? Beer tokens ok.

-- Peter Fairbrother

Reply to
Peter Fairbrother

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.