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Alistair Hosie
05-22-2009, 02:59 PM
I am changing my lathe habits not my lathe ways.I had a visit from two very dear friends of mine last week when it was my birthday these guys are both great engineers.One JIm a mathematics lecturer and engineer by profession,quickly said oh I never use tungsten indexable cutters I always use h.s.s he tried my lathe and pronounced that I was cutting very poorly as my tungsten cutter was blunt and badly syharpenned from a previous encounter with the sharpenning machine I bought for the job.Anyway I now have to get used to sharpenning h.s.s cutters again and using them I always knew they were better for finishing but never realised by how much.Now I know a Lot of you need to do a lot of rough cutting and tungsten is the way to go But I am going to take his advice and give h.s.s a try once more.Alistair

Norman Atkinson
05-22-2009, 05:25 PM
A,
I'm just downloading a heap of info.which may be of interest

Cheers

N

toastydeath
05-22-2009, 06:42 PM
I'm not sure why you're blaming the tooling material for a poor finish when you've said the tool was beat?

I use carbide and indexable tooling on all the lathes I have access to, which includes many manual machines. I don't have any problems with surface finish.

This topic has come up many, many times. I still don't support that HSS gives a better finish by some innate property of the material. It's down to the user to select the right insert in the case of inserts, and also to ensure the tool has a proper edge on it in the case of brazed. Not doing it properly isn't a reason to insult the tooling material.

This is one of the inserts I use for general finishing. Uncoated, with some minimal polishing. Not a huge amount of positive rake, but something in the 7 degree ballpark. Basic chipbreaker.

http://photos-g.ak.fbcdn.net/hphotos-ak-snc1/hs007.snc1/4173_179059180082_692245082_6987998_5174443_n.jpg

This insert leaves a better finish than most can achieve with an HSS tool.

Edit:

Just to clarify, I also use a ton of HSS. It just doesn't matter to me what tool I'm going to use, I don't understand all this nonsensical arguing about HSS vs. carbide tools or why someone would have a very strong opinion on the subject.

Carld
05-22-2009, 08:13 PM
I agree with toasty, there are places to use carbide or HSS. The tip finish on carbide depends on what your doing. For rough cuts it's best if the cutting edge is slightly dull but for finish work it's best with the finest sharp edge you can get and hone it with a diamond stick. It's much the same for HSS cutters. When roughing with a HSS cutter the cutting edge is soon dull but still does good roughing. When you get to the finish work you have to sharpen the cutter as good as you can get it and lap it on a stone.

There are places to use each one and I use HSS for large radius cutting most the time.

To say one is better than the other is myoptic in my opinion.

Mcgyver
05-22-2009, 09:50 PM
Just to clarify, I also use a ton of HSS. It just doesn't matter to me what tool I'm going to use, I don't understand all this nonsensical arguing about HSS vs. carbide tools or why someone would have a very strong opinion on the subject.

i think its analogous to whether you'd use steel or AL for a part. The sensible way is to select the material based on the application, available resources etc.....it would be nonsensical to just always use steel or AL proclaiming it superior.

same with tool bit material. It can matter which you use and for a given circumstance; there is a rational engineered choice that does make one better than the other ....and it is the innate properties of the tool material that determine that.

For example, the best finish i've seen on 1018 is out of large carbide equipped machining centres. its an innate property of carbide that it can withstand the temps that produce that finish. Similarly on lighter machines, its an innate property of hss that permits a more acute cutting angle of hss and resulting lower cutting forces ....point being that it is the innate property materials that affect finish and the right tool for the job is determined by circumstances at hand

the discussion may appear more black and white to some because with the lighter nature of home machines, hss is often the better choice. However that's not anything like same as one is better or should always be used. The only part of this tiresome reoccurring theme that i think warrants attention, is the newbies who I think often select carbide over hss not for engineering reasons but because they erroneous think sharpening a tool bit is difficult.... empower yourselves! It's as tough as tying a shoe lace, you once perceived that as a big challenge but with very modest effort quickly viewed it as easy. Then,once you can do both, you can rise above the silly this or that one is better and select the best for the task at hand

clint
05-22-2009, 09:51 PM
Instead of HSS for finish work try ceramic inserts, I have some TPG ceramic inserts that give outstanding finish cuts on aluminum, stainless, and titanium...cheap off ebay. They are worthless for interrupted cuts, but anythings else is easy cutting, 3 sides would last forever, and a day...

I'm not a big HSS fan, that's just me, to many cheap inserts on ebay ( well used to be) and to little time.

BadDog
05-22-2009, 11:54 PM
I also agree with Toasty.

I love my HSS. Special grinds give me fillets, grooves, shaving tiny amounts, and fine finishes. I've also got some ground and mounted for tiny ID and OD chamfers and such without turning my tool block.

I love my inserts. My lathe (before it coughed up a spindle bearing) would happily drop 4140/4340/etc. steel 0.500 without breaking a sweat. Cast iron, hard steel, hot rolled scale, no problem. Coated, plain, polished, there is something for everyone.

I love my brazed carbide. Happy medium between HSS and Inserts. More flexible in some cases, and readily sharpened/shaped at home (don't tell anyone, but I've been known to sharpen/shape insert... shhhh...).

A very nice fellow also turned me onto Cermets. Amazing inserts that can take very small cuts at 1000 sfpm and leave unbelievable finishes.

The right tool for the job...

Norman Atkinson
05-23-2009, 02:50 AM
Gentlemen,
I think that I should clear the air somewhat of my views.
I was addressing friend Alastair and who, like me, is retired and has a lathe etc for a hobby.Neither of us has earned a crust from a lathe nor ever needed to. Consequently, our machinery is small(ish) and somewhat flimsy and definitely underpowered.

If you really want a pi55in' match about hss and carbide, the true test is that
you have to earn a crust, we don't.What you need to earn to earn your crust, keep you in the lap of luxury or whatever your wife or bank manager decrees- is up to you. If you need a bloody big lathe complete with the latest gimmicks- bloody good luck 'cos you'll need it.

Sorry, I might have killed a few sacred cows-- but there is another way to play with a lathe--- and not having to earn a crust.

Let's put this into perpective. If I went out to buy a bloody big monstrosity and heap of fancy shrapnel which will tear the arse off a tank, I would not only lose money but would have all my neighbours queueing up to complain that the value of their property had hit rock bottom- and was dropping into a mineshaft- God knows where.

So let me finish my rant- and get on with the simple task of passing on a few of my experiences-- gained from farting about over- it must be 76 years now.

Somewhere in 1933, a snotty nosed kid with could hardly see over his father's blacksmith's anvil and watched him weld carbon steel inserts onto wrought iron holders. In 1941- I was watching him sticking carbide onto a mild steel shank to make his own tooling.

Gentlemen, please don't teach me how to suck eggs, or make an omelette.
You could tell me how to the story of how to make the Philosopher's Stone or the secret of everlasting life but at almost 79 now-- I am too deaf to listen.

AND if I could hear, it would be a load of bollocks.

Norm

Circlip
05-23-2009, 04:06 AM
Ahem, just what he said.

In common use there are about 3 grades of HSS, when you look on the magical Flea, the cocophony of Alphabetical/numerical "Inserts" displayed beggars belief. And please, no references to the insert explanation charts, lifes too short.

Regards Ian.

davidh
05-23-2009, 09:47 AM
"farting about", "sucking eggs", "earn a crust", norm, i would love to hear you in any conversation. the british accent, the little blurbs that are never heard on this side of the pond,

i for one, enjoy your input, your writings and your british slang. . . .it brightens my day.

keep it up.

(another old guy)

davidh

tony ennis
05-23-2009, 10:25 AM
I'm still not sure what language Norm speaks.

dan s
05-23-2009, 10:45 AM
why is it every time we hit on Carbide VS. HSS, all the loonies come crawling out of the wood work.

If you want to compare cost, that's one thing, some of the other "opinions" tossed around on this board are just complete BS.

Circlip
05-23-2009, 11:20 AM
Norm speaks surrealism Tony.

I hope you classified ME as a loony Dan ?? Cos I'm proud to resemble that remark.

Regards Ian.

moe1942
05-23-2009, 11:24 AM
HSS steel is all the HSM needs. The nay sayers are usually the ones without the talent to grind and shape it properly. I have lots of carbide but always grab the HSS.

But I'm still young compared to Norm, only 66, so that could change.

moe1942
05-23-2009, 11:25 AM
I'm still not sure what language Norm speaks.


From real life experience, when there were real men.

dan s
05-23-2009, 11:49 AM
The nay sayers are usually the ones without the talent to grind and shape it properly.

O my, another prepackaged shot from the HSS is the best group.

I use both on my lathe (8x14), and the main benefit of HSS in my shop, is the ability to make custom bits.

dan s
05-23-2009, 12:04 PM
From real life experience, when there were real men.

well that sure sounds like the fall back response of a grumpy old man.

Norman Atkinson
05-23-2009, 12:25 PM
Oh dear, oh dear!
Am I one of the few here who has------qualifications in-- studying American English and Literature? Oooh, Matron? And -- ooooh- weee- I did American Constitution, as a party piece. I can't quite remember when- but I reckon that there will be few hands here that can manage the equivalent trick in English Language and English Literature.

To be fair, I actually enjoyed the whole experience.

Makes you think? I should cocoa.

Norm

dan s
05-23-2009, 01:11 PM
Norm, are you Welsh?

Mcgyver
05-23-2009, 01:30 PM
I use both on my lathe (8x14), and the main benefit of HSS in my shop, is the ability to make custom bits.

the main benefit in a very light lathe is the reduction of cutting force required for a given doc/feed as rigidity and power are the two main constraints....agreed special tools are also an advantage, but its not one dimensional


If you want to compare cost, that's one thing, .

why is it ok to discuss dollars and cents as being relative but not engineering and performance? imo it all should all get factored into the choice


some of the other "opinions" tossed around on this board are just complete BS

that is a broad statement - what do you see as BS and why?

Norman Atkinson
05-23-2009, 01:47 PM
Dan,
Welsh- look you, boy-oh? Nah!

But then again, I might be. The story is that my father was a sapper and stationed in Wales- on the island of Anglesey. The story is that he set fire to a horse. Well, the stupid thing decided that it was going to have a day off.
The British Army wasn't quite in agreement and Dad had the luck to draw the short straw and- well, it was only when he put some hay or straw under the cart and set fire to it that there was ---------------------------------
movement.

Obviously, my father, the boy wonder was too much of an asset to the Army that he continued to train other recruits in bridge building until the end of the Great War. Dad was 17!!!!!!!

Where did I get? Oh, yes! Time came to fall in love- not just with horses and my mother and he went back on honeymoon.

The rest is - history( and not too important history)

Welsh Wales? Recent history? Well, my missus and I were having a beer with the former Lord Lieutenant's widow only the other day. The discussion was whales and as she came from----Whitby in't Yorkshire( Ian, please note)
She is batting on in years- the Old Bat and sold up the family castle or something- it had 2 toilets, so it had to be a castle and they found a pair of narwhal tusks in the coal house- and a rhino horn.

Oh, I Hell, my wife's lot have another castle.

I've sort of got lost, a bit.

Would you settle for the Prince of Wales being a sort of relative?

Norm

dan s
05-23-2009, 01:59 PM
the main benefit in a very light lathe is the reduction of cutting force required for a given doc/feed as rigidity and power are the two main constraints....agreed special tools are also an advantage, but its not one dimensional

The reduced cutting force is because of the "rake". Inserts can now be purchased, that have as much "rake" as hand ground HSS.

Carld
05-23-2009, 02:25 PM
It seems some have forgotten or ignored what Alistair said in his opening post. He seems to have been using carbide inserts and maybe having trouble and his engineer friend said he NEVER uses carbide but always HSS. As I said, that is a myoptic (near sighted) opinion. There are times where HSS would just burn up and not cut the work.

From that point some pointed out the features of both cutters. Then some said that HSS should only be used. The fact is that both have their places and to use one all the time may not be the best way. For most home shop work HSS will do nicely but at times only carbide will do and it doesn't have to be the insert tool holders.

Even home shop machinists will need carbide from time to time and should learn how to use both HSS and carbide. I don't think many home machinists need insert cutters but again, it's something they need to decide for themselves.

If you can sharpen HSS then you can sharpen carbide, the only change is the type wheel you use to sharpen with. There is nothing magic about sharpening lathe tools.

I just don't see why anyone would promote HSS or carbide as the best because they both have a place to use them. I have two large drawers with carbide in one and HSS in the other. A lot of them are ground to various shapes that I have needed over the years and I use what works for the job I am doing.

Peter.
05-23-2009, 04:28 PM
I only use HSS currently, haven't got round to buying-up any carbide insert tooling. I did a little job a couple of weeks ago lightening a BMW flywheel for my mate Frankie. When I came to dressing the face that the clutch driven plate rides on it had work-hardened so much I couldn't cut it. Ground my bit with all sort of rake/profile with no luck then Frank went off and came back with a carbide insert tool and it cut right through the work-hardened part of the face then I went back to HSS to finish it.

I guess there must be a way to do the same using just HSS but for my novice efforts weren't up to it!

Norman Atkinson
05-23-2009, 05:03 PM
But Peter, the oldies would have used CARBON steel!
Back to square one. You may have to cut your toe nails to case harden the tool but that was the way. Somewhat cruder, you could have crapped on the tool and stuffed it into a piece of old iron pipe and blew the whole lot up in the furnace.

It's called ENGINEERING or Chemistry or a smelly business but you came out of a rather nancy world.

Explosives were made by everyone having a good pi55 or getting some bird to do it.

All that is needed now is to know what time the shop opens.

Weve got a guy who came from a College which was there long before some creep buggered off in a wooden boat across to where they finally made it- or didn't- and forgot how things worked. Me, I came from a place where the shops were for rich people. My father used to temper with a bit of charring wood and watched the smoke.

It was called engineering- and it still is.
N

Peter.
05-23-2009, 05:20 PM
Funnily enough Norm I also grew up on Anglesea and you know what that means <insert sheep-joke here>. My grandfather once made a set of piston rings from my grandma's flat-iron (and caused a row that lasted 15 years). Anything I wanted, I made myself or went without so no, I haven't really been handed life on a plate. Even today when I can afford to buy stuff I'll always look to see if I can make it first and not because it's cheaper (it rarely is).

Norman Atkinson
05-23-2009, 06:09 PM
Peter,
Anglesey- hummm? but I, too, live on a very small island. It sort of teaches a degree of self sufficiency.Maybe one starts to think differently.
Mine's the little blue and white island of Menorca but it is odd to think that historically Anglesey and Menorca are much the same.

Am I bonkers to suggest that measurement came from both islands?
Read up Professor Thom and Megalithic Man on your island.
I, too, have the taulas and talyiots of ancient man.

It wasn't friend Whitworth or Vernier that 'invented' them. Read up Knight and Lomas on the Book of Hiram. I guarantee that it will change your perspective.Moreover, it will de-bunk one's elated thoughts to what they should be.

I'll leave you to the summer solstice on your island.

Creepy

Norm

Spin Doctor
05-23-2009, 06:17 PM
I'm a firm believer in the idea that carbide can might or exceed any surface finish that HSS* will produce. It is a matter of SFM. Carbide used at too low of a speed will NOT produce a good finish. Too often poor surface finishes with carbide result from improper speeds (too slow), too little or too much feed, lack of rigidity in the tool hloder and the wrong tool nose raduis for the application. There is no one insert for every thing but the one type shown in the link on the first page comes close as any I have seen. It will produce a good finish on longitudinal and facing cuts, both in and out. But they require enough feed per revolution or they will have swarf dragging behind the tool nose rubbing on the woork screwing up the finish. At the same time I do not believe in carbide for threading on the average HSM lathe as they are not reliable enough at the spindle speeds required for cutting good threads. For threading with carbide on a manual lathe you really need something like the set-up on a Hardinge where you are not having to watch a threading dial at 500 or so RPM. :eek::eek:

* And on hardened steels CBN is fantastic. Just make sure there are no inturupted cuts

lazlo
05-23-2009, 06:23 PM
The reduced cutting force is because of the "rake". Inserts can now be purchased, that have as much "rake" as hand ground HSS.

Yes, but the high rake aluminum inserts that non-HSS grinding HSM'ers seem to like are very fragile. Heck, any positive rake carbide insert is fragile -- the aluminum inserts are just an extreme positive variant. That's why commercial machinery uses negative rake carbide: the edge is 90, (instead of 75 or less on positive rake inserts), so they're much more durable.

As you've probably experienced, if you grind a steep rake angle on a brazed carbide tool, it's just as fragile, and cuts just as well, as those expensive aluminum inserts.

Carbide is very hard, but very brittle. HSS is softer but much tougher than carbide. So you can grind a very sharp edge on a HSS tool to minimize cutting forces on a small, HSM lathe, and keep that edge for a long time.

Mcgyver
05-23-2009, 06:34 PM
The reduced cutting force is because of the "rake". Inserts can now be purchased, that have as much "rake" as hand ground HSS.

but those inserts do not have the same strength so they can't be used on the same materials at the same DOC, feed etc.....hss and carbide two are two different materials and their different properties means engineering and cost differences makes one or the other a better choice under given circumstances, They're not interchangeable and there are usually reasons why its best to select one over the other.

unless its hard stuff like in Peter's example, in light of the above, for general use, why would one use carbide on a small light lathe? Have at it anyway you want, its supposed to be fun after all....but I think its often done because some newer guys aren't comfortable sharpening hss ......which is why I keep harping that they'll be surprised both how easy and beneficial it is to learn.

dan s
05-23-2009, 07:02 PM
Yes, but the high rake aluminum inserts that non-HSS grinding HSM'ers seem to like are very fragile.

I wasn't talking about those.....

several of the insert makers now have Negative seat inserts that still yield plenty of positive rake, like this one for example.
http://www.carbidedepot.com/detail.aspx?ID=52930


Personally, I think the number one reason so many people call carbide "crap" is because it's not nearly as forgiving as HSS. With carbide several things can lead to a frustrating day in the shop.

low sfpm
wrong feed
wrong tip radius
wrong chipbreaker
wrong grade

dan s
05-23-2009, 07:16 PM
unless its hard stuff like in Peter's example, in light of the above, for general use, why would one use carbide on a small light lathe? Have at it anyway you want, its supposed to be fun after all....but I think its often done because some newer guys aren't comfortable sharpening hss ......which is why I keep harping that they'll be surprised both how easy and beneficial it is to learn.

I started out using nothing but HSS, and still have several cases full of them. I switched primarily to inserts for two reasons:

it's a lot easier to make small chips with inserts than it is with hss, that is unless you have an expensive tool & cutter grinder, or the decades of experience like Harlold to freehand grind chipbreakers.
Time savings: As my work days have gotten longer (11 hrs seams about average now), I want to spend my time work on the project, not grinding a tool to work on a project.

lazlo
05-23-2009, 07:32 PM
Personally, I think the number one reason so many people call carbide "crap" is because it's not nearly as forgiving as HSS.

I don't think anyone here is saying that carbide is crap. But like McGyver says, the principal reason hobbyists use carbide on a light-weight HSM machine is because they're unwilling, or unable to learn how to grind a HSS tool.

Carbide inserts are made for high surface speeds/feeds on heavy, rigid machines in a production work environment. You can absolutely use carbide inserts in a home shop -- most everyone here (including myself) does, but for a lightweight machine, a properly sharpened HSS tool is superior in most ways, except for hard stuff like 4140 Pre Hard.

By the way, you linked to the *NMG Trigon inserts: negative rake inserts with a positive rake chipbreaker. I love those -- I use the CNMG's (the 60 diamond versions) on boring bars to rough out, but they take a heck of a lot more power and rigidity than a try positive rake insert like a CCMT. The flip side is that a CMNG is a lot more durable than a CCMT. But it's still really tough to take a light enough cut to sneak up on a diameter like you can with a razor-sharp HSS tool.

bborr01
05-23-2009, 08:05 PM
How many of you guys are still using steel blades on your table saws, miter saws, circular saws, router bits, etc.
It is much the same argument with machine tools. I have HSS tool bits that I have ground for cutting internal threads, Internal O-ring grooves, and many other applications where carbide is too much hassle to grind.
Try cutting some Thompson 60 case with HSS. It aint happening. I have made many shafts out of case hardened steel where I turned the case off and then threaded the shaft.
The main thing about carbide overall is it lasts so much longer between sharpenings. And its ability to cut hard steel. As was stated in a previous post, the main reason some don't like to use carbide is that it takes a special wheel to grind it. Most guys would rather buy a $10.00 wheel than a $200 diamond wheel.

I've seen in many other threads about a lot of guys using green (silicon carbide) to grind carbide. They are fine for roughing something out but leave a sub-standard finish on carbide. If I were grinding carbide tool bits with a green wheel I would expect to get poor results while turning.

Carld
05-23-2009, 08:49 PM
It is no harder to learn how to grind HSS than brazed carbide lathe tools. That is, if you have a bench grinder with a good adjustable table or a grinder designed for lathe tools. I used a bench grinder at home untill last year when I bought a HF tool grinder. I used a green wheel for a while like we did at the places I worked but then I bought a diamond wheel for about $70 and it was the best buy I have ever made. I cut the sharpening time in half or less and get a much better finish on the work.

The only way to learn how to sharpen lathe tools is to do it. The problem is most people get disgusted and give up to soon and they may be using the wrong or defective equipment.

I rarely use insert tool holders at home but I do use a lot of HSS, Cobalt HSS, and brazed carbide. It may take all three of them to do a job.

Mcgyver
05-23-2009, 08:51 PM
Dan, I agree with you its not either or, and i don't know anyone who calls carbide crap.

hehe, Harold. In between him telling whoever will listen how great he is and how long he's been in the trade he does offer some good advice, but he's so concerned with his self efficacy he leaves the impression you're scuppered unless you've been doing it for 45 years. Disagree on anything and rather than a rational response you get slapped down as he recites his resume. Anyway, it didn't take Harold 10 years to learn to grind a chip breaker, it took 15 minutes at the bench grinder after thinking about what material needs to be removed to get the shape wanted, same as it took me and same as it'll take you.....

Norman Atkinson
05-24-2009, 03:17 AM
Well, so far poor Alastair will be nowhere in all this prattle which has really extended to 2 whole topics.

But look again! He did get ONE constructive reply- I downloaded some 100 odd pages on the the subject- immediately.

For the rest of this, he could be chucking 'snowballs at the moon'

Hummmmph! ( and I go off at tangents----bollocks)

Norm

moe1942
05-24-2009, 09:51 AM
It's amazing what some can read into the written word. I can't find a post in this thread where someone said carbide was crap. I still maintain that HSS is all the HSM needs for 98% of the work. That is taking into consideration the type of equipment the average HSM has. Very few have the deep pockets to outfit their shop with high speed production type lathes. Smaller, light duty lathes don't digest neg rake tooling well either..

As I said, I have quite a bit of carbide tooling but rely almost totally on HSS. This is only my opinion.

Also, there are different grades of HSS.

Alistair Hosie
05-24-2009, 04:51 PM
Well seems like my friend is wrong !!! Oh well in a sense I have a lot of carbide tools too many for a Scotsman or a canny northern Englishman eh Norm to throw oot laddie. Anyway I will change the tip and persevere.I asked also because David my friend Mr Coffer whio happens to be a good old pal of mine said he preferred them to carbide many years ago in an article are you listening David and do you still prefer hss or have you moved on a notch ????? Many thanks for your kind input gentleman I do appreciate it and will definitely try again as said. Norm is half correct I don't make a penny from what I do in the shop but my lathe is a substantial Smart and brown 1024 bvariable speed with d1-4inch camlock so it's as good as it gets it was used for anumber of years sparingly by Oxford university and was made in 1983.
Alistair