Indexable lathe tools

[Adam HarrisParticipant @adamharris13683]

Hi Jason, it is a Komet Unisix (after lengthty searching of indexable tip photos!!). http://www.komet.com/pdf/kompass/Chapter_7.pdf

Now I just have to work out how to decipher the codes to find out which ones fit the Myford and which are suitable for different materials? Any advice? Adam

[Adam HarrisParticipant @adamharris13683]

Should this be of interest to any members, the size of Unisix indexable tip for the Myford 12×10 tool holder MUR12R90 is P01, and the Komet equivalent code (Hoybide no longer make them) is W04_34xxx.xx.xx for the Left , Right and Neutral cutting types. Thanks everyone. Adam

[stan pearson 1Participant @stanpearson1]

I know I am going off the question but I don't know why model engineers rave about indexable tools when you get a far better finish with a properly ground HSS tool. When you say you shouldn't chip them I do and they are at the proper height and not run into stationary objects .

Stan

[Anonymous]

Posted by stan pearson 1 on 23/06/2014 22:29:22:

……. you get a far better finish with a properly ground HSS tool.

Stan: Interesting, I know what sort of surface finish I can get using carbide inserts, for comparison I am curious as to what sort of Ra value you would expect to get on say, EN1A, using a HSS tool bit?

Regards,

Andrew

[stan pearson 1Participant @stanpearson1]

Hi Andrew

I have never used EN1A so I don't know, but most of the mild steel I get is EN8 or I do use some stainless for small bolts and studs. The main problem I have is they chip easily, I can get a good finish with a sharp HSS tool with the cutting edge rubbed off with an oil stone. When I spoke to a turner he told me they are ok on big lathes taking cuts of 1/4" or more and running red hot, they don't suit the small 31/2" lathe taking fine cuts.

Regards

Stan

[Douglas JohnstonParticipant @douglasjohnston98463]

If you use a good quality positive rake carbide tip you can get a superb finish even on the smaller hobby lathes. I think many people are put off carbide tips after trying poor quality or inappropriate types. If you look at a solid carbide milling cutter, the edges are very sharp and give an excellent surface finish. Lathe tips of the same quality will produce excellent results as well, but don't expect good results from cheap imported tips of dubious origin.

Doug

[Tim StevensParticipant @timstevens64731]

I just found this site page which may be helpful:

http://www.shop-apt.co.uk/torx-screws.html

It is clear that the options of size, pitch, torx-size, length, etc is endless. Good luck with your hunt.

Cheers, Tim

[Neil WyattModerator @neilwyatt]

At Harrogate I asked JB Tools what they recommended for a small lathe, the answer was:

CCMT060204 (gold colour) for most materials.

CCGT060204 (silver colour0 for aluminium alloys and stainless.

Three inserts and a holder to suit my mini lathe for a very good price.

I haven't tried the silver one yet, but I was able to peel blue chips off alloy steel and get a good finish on mild steel with it.

"Your mileage may vary"

Neil

[JasonBModerator @jasonb]

You will like the CCGT ones, also very good on brass and bronze, the swarf comes off in a long curly ribbon not loads of fine chips that go everywhere.

 

J

Edited By JasonB on 25/06/2014 20:02:53

[Anonymous]

From measurements I get surface finishes on the order of 2µm Ra using carbide inserts on most materials. Horrid materials like EN3 tend to be a little worse, easy ones like 6082 and 303 stainless steel are better. By eye the finishes I get with HSS tooling seem similar; for completeness I should do some experiments and measure the finish. I tend to use HSS on the centre lathe only for specials such as form tools and grooving. I use HSS exclusively on the repetition lathe, but I'm usually in a rush to get parts made and out when using it.

Depth of cut depends on material. For low carbon steels a doc of 10 thou minimum seems to be needed for a good finish. But that's not a problem, if I need to take 21 thou off the diameter I expect to dial in 21 thou and get a 21 thou reduction. For most other materials carbide seems quite happy giving a good finish at low doc.

I find that carbide is pretty robust; I've done a lot of heavy interrupted cutting on large lumps of cast iron and steel without chipping inserts. Wear them out certainly, but not chip. Like JasonB says the main danger is finger trouble running the insert into stationary work.

I try and aim for a consistent and uniform finish as much as a given Ra value. I don't have the time or interest to spend ages finishing parts off with emery cloth and files. I expect to be able to use parts straight from the machine, with the exception of deburring.

Regards,

Andrew

[MuzzerParticipant @muzzer]

The swarf generated depends on the cutting conditions but ideally it should break into chips as it comes off. Often our light machinery struggles to achieve this due to the limited rigidity and spindle power available but it's nice if you can manage it. Apart from anything else, you need high speeds to get a decent finish, so if you are getting continuous ribbons coming off, it can be pretty dangerous. So I try to turn the speed up as high as the machine will manage and this will often get it to where the chips break up – it's how they are intended to be used after all.

It's worth reading the data sheets for the inserts and getting the DOC, feeds and surface speeds somewhere close to where they should be. The surface finish may miraculously improve beyond what you had previously managed to obtain…

Murray

[stan pearson 1Participant @stanpearson1]

Andrew

Just been reading the article on EN8 finish it appears I am not on my own using HSS to get a good finish

Stan

[Anonymous]

Stan: Quite so, but since no-one else has put any numbers on the finishes that they obtain it is all rather meaningless. A 'good finish' to one person might be a roughing cut to another.

As and when I get the time I'll grind up a HSS tool and have a go at some comparative tests.

Andrew

[Clive HartlandParticipant @clivehartland94829]

I am surprised sometimes by the use of indexable cutting tools, in industry they are used mainly for gross metal removal to bring a component made of tough materiel to size quickly. But, they do not use them for cutting the seats of bearings and shoulder. That process is a secondary process perhaps after hardening when the precision surfaces are ground to size.

Now we have amateur/model makers using them for precision work to size and having difficulty getting a good finish on the metal, I quite agree as the tipped tools require to cut metal of at least a 20 thou cut. These tool tips have a shearing action that does leave a poorer finish as the feed rates are high. Secondly, most model makers machines do not rotate fast enough for these tools. Shallow cuts and tipped tools mean that they skid over the work.

HSS of a good quality will do all that you ask of it and can be ground to certain shapes for special jobs. It can be used at lower speeds on all materiel that we use. I have some tipped tools that I only use when I need to machine hardened items and even then they make my machines grunt a bit.

If you are machining correctly with the right feed and rotational speed your chips will come off blue, this is correct. Only on ferrous, not on softer metals. Even turning wood, the tipped tools wear and I find that they are not sharp enough and tear the wood. I find HSS much better for this type of work. Experience is the thing here, if one tool is not doing what you want then change to another or see if its the right tool for that job. One thought is that specialised metals need specialised tooling, tipped tools are NOT good for everything.

Clive

[gerry maddenParticipant @gerrymadden53711]

I use the silver CCGT (which are suposed to be for aluminium) on everything. They are incredibly sharp and seem to cut beautifuly all materials, at any speed very nicely indeed. I have some gold ones too and they also work well but seem to need higher cutting forces than the supersharp CCGTs.

One area I havent tried the silver ones is in cutting 62HRC bearing steel. But the gold ones manage this. First time I did it I was a bit shocked to see red hot spirals of swarf shooting out and got a bit worried that I might set fire to the bedroom carpet !

G.

[Ian PParticipant @ianp]

Posted by Clive Hartland on 01/07/2014 14:41:16:

I am surprised sometimes by the use of indexable cutting tools, in industry they are used mainly for gross metal removal to bring a component made of tough materiel to size quickly. But, they do not use them for cutting the seats of bearings and shoulder. That process is a secondary process perhaps after hardening when the precision surfaces are ground to size.

Now we have amateur/model makers using them for precision work to size and having difficulty getting a good finish on the metal, I quite agree as the tipped tools require to cut metal of at least a 20 thou cut. These tool tips have a shearing action that does leave a poorer finish as the feed rates are high. Secondly, most model makers machines do not rotate fast enough for these tools. Shallow cuts and tipped tools mean that they skid over the work.

HSS of a good quality will do all that you ask of it and can be ground to certain shapes for special jobs. It can be used at lower speeds on all materiel that we use. I have some tipped tools that I only use when I need to machine hardened items and even then they make my machines grunt a bit.

If you are machining correctly with the right feed and rotational speed your chips will come off blue, this is correct. Only on ferrous, not on softer metals. Even turning wood, the tipped tools wear and I find that they are not sharp enough and tear the wood. I find HSS much better for this type of work. Experience is the thing here, if one tool is not doing what you want then change to another or see if its the right tool for that job. One thought is that specialised metals need specialised tooling, tipped tools are NOT good for everything.

Clive

Clive

I am not surprised that indexable tipped tools are used in industry, if they had to use HSS etc they would need teams of people to grind them! Its also not true to say they only use them for gross metal removal, in reality they are used for virtually everything on a wide range of materials.

The Carbide versus HSS topic is never going to have one answer and frequently gets regurgitated on this and other forums. I use a mostly carbide but also use many HSS tools mainly because they can easily be ground when I need a specific shaped.

Some time ago I bought a set of five holders and each came with a triangular tip. I can only describe the tips as pure and utter rubbish! If they had been my introduction to indexable tools I would have been put off for life. I would not be surprised if the same thing had happened to many others and they are now in the 'HSS is best' camp.

There is vast range of tip types available to industry, however understandably most of the suppliers to the model engineering world only stock a limited range and getting the best out of them is really only found by trial and error on ones own machine and circumstances.

20 thou cut minimum, high speed, big machines etc is often bandied about when decrying carbide but its only true some of the time. I have some carbide tips (designed for using on aluminium) that have high top rake and razor sharp, polished, cutting edges, I use them with care on carbon and stainless steel to turn diameters well below 1.5mm.

Ian P

[Neil WyattModerator @neilwyatt]

It's interesting to read the Wikipedia page on cutting tools, it explains why carbon-steel and HSS tools are sharp, and why carbide are 'blunt' and the different ways in which they cut.

**LINK**

Which goes a long way to explaining why these 'orses suit different courses.

Neil

[mickParticipant @mick65121]

I've dipped my toes in this murky water before. To my mind Its probably best to buy inserted tooling from a supplier that advertises to the model engineering fatuity, as the grade of carbide and tool shape they supply will be a happy half way house that will preform well in a variety of different applications.

To try and get industrial style inserted tooling to work in a hobby environment is only at best a get out of jail option.

When I worked in industry I use to favor the double side triangular style of tool holder, but had different inserts for just about every material I machined on a regular basis. If the inserts were placed side by side its virtually impossible to see the difference between, but difference there is when machining, a stainless steel insert will preform poorly when cutting cast iron and visa versa, cast iron inserts preform badly when cutting anything but cast iron.

[Adam HarrisParticipant @adamharris13683]

As the person who started this thread and also the person who likely knows the least on the subject, it is very frustrating to read all these lengthy opinions that obviously come from experts but offer in reality no practical help to anyone! It is common sense that different tips will offer different performances on different metals (however slight or great), and common sense that HSS may work well in many circumstances, but what WOULD be of practical help is if someone could list which tips they personally recommended on model engineering lathes for which type of cuts (roughing out, medium or finishing) for which materials.

[Oompa LumpaParticipant @oompalumpa34302]

Posted by Ian Phillips on 01/07/2014 15:33:30:

Some time ago I bought a set of five holders and each came with a triangular tip. I can only describe the tips as pure and utter rubbish! If they had been my introduction to indexable tools I would have been put off for life. I would not be surprised if the same thing had happened to many others and they are now in the 'HSS is best' camp.

Ian P

So Adam, there you have it. This is the problem you have and as Ian points out it can put you off for life. I was given a couple of tips to "try" recently and I destroyed them before I had actually made one full pass on the material I was working on!

There is no one single magic answer and the range of tips and styles is just bewildering. Even using the reference guides I get totally confused sometimes. However, this was some advice given to me and it has worked so far: Buy some Glanze holders from Chronos and buy some Sumitomo tips from Arceurotrade. This combination is by far and away the most reliable. So far I have yet to wear out or break (this will happen tomorrow) the first Sumitomo tip I fitted to one of my holders for roughing out of Aluminium. Sure, they may appear expensive, but if you go through half a dozen £3.50 tips and one £6.50 tip in the same time………..

I use the CCMT style tips and would not hesitate to recommend them. I also use HSS tools but for Aluminium and Brass/Bronze I wouldn't use anything other than Indexable. It has worked well for me for a while now. And the lathe I use them on is quite small, not an industrial machine at all.

graham.

[Adam HarrisParticipant @adamharris13683]

Thanks. So Sumitomo TCMT/CCMT tips from Arceurotrade for Aluminium and Brass/Bronze roughing (and finishing?) cuts, and maybe steel, but HSS also good for steel. Would you bother to choose a Sumitomo CCMT specified as "Finishing" for finishing and "Roughing" for roughing or do you use "Finishing " inserts for everything from roughing to finishing?. What about stainless steel and cast iron (roughing inserts and finishing inserts)? For CCMT inserts do you follow the standard material speeds as recommended for HSS bits or do you run the lathe at maximum speeds regardless? Ideally I would like to make myself a simple matrix for 5 materials (Steel, stainless, cast iron, brass/bronze and aluminium), vs recommended index tips for each , vs best material speed for each, vs 3 types of cut (roughing, medium and finishing). Then I would be finished bothering our patient forum members!!

[SteamgeekParticipant @steamgeek]

In the last 12 months I have started using CCGT tips , which are generally listed for use with aluminium and brass, and they work incredibly well on those materials. However the also work superbly as a finishing tool on steel. I have been able to make controlled cuts of 0.5 thou using these inserts and the finish is very good.

So I now have 2 right hand knife tools, one set up with a CCMT 06 insert which easily takes 20 thou a side and one set up with a CCGT 06 insert which I switch to when I get within 10 thou of finished dimension.

I should add that I generally do not try to cut more than 5 thou a side with the CCGT insert on steel

[mickParticipant @mick65121]

Well Adam, the only inserted tools I use on a regular basis on my Myford are a couple of Glaze right and left hand profiling tool holders and a rear mounted parting blade. I have a couple of screw cutting tool holders on a 20mm squ. body, which, when mounted on a couple of 5/16'' strips directly to the compound slide base gives centre height. The rest of the industrial tool holders I have acquired over a working lifetime remain in the tool chest.

[Anonymous]

Posted by Adam Harris on 01/07/2014 18:25:47:

As the person who started this thread and also the person who likely knows the least on the subject, it is very frustrating to read all these lengthy opinions that obviously come from experts but offer in reality no practical help to anyone!

Well, that's charming innit. Since I haven't done exhaustive tests on all types and makes of insert and different materials, and I don't have what might be termed 'model engineering' lathes I can't help.

Out of interest I've just measured the surface roughness of the inner bore of a bronze (SAE660) bearing I machined a couple of days ago. Finishing cuts were with a CCGT insert, 540rpm, 4 thou per rev and doc 1thou; the result was an Ra of 1.45µm.

Andrew

[JasonBModerator @jasonb]

Posted by Adam Harris on 01/07/2014 18:25:47:

……………….. is if someone could list which tips they personally recommended on model engineering lathes for which type of cuts (roughing out, medium or finishing) for which materials.

A lot will depend on what you term a "model engineering lathe" I know someone who ises insert tooling on a little Cowells lathe and they also have a Colchester Master in the shed and several other lathes in between, all used soley for hobby model engineering.

This is what I'm currently using on my Warco WM280, which is a bit bigger than a myford but if you believe what you read about imported lathes not as tightly made!!

Aluminium, Brass & the Bronzes CCGT tips, I'm still on teh Chronos ones I bought about 2 years ago but do have some Sumitomo one for when if they wear out as they are lasting very well, I keep one in a RH holder and another in an 10mm boring bar all the time.

Steel for most general work I'm using Kennametal CCMT 060202LF inserts which have a small 0.2mm radius tip and as the LF (light Finishing) signifies are good for lighter cuts, I can easily take 0.001" depth of cut off steel with these unless its very long and slender. They will still quite happily take 0.050" cuts as well. I always have these set up in the following quick change holders, R/H, L/H and two boring bars

For roughing out I don't use a specific insert but I do have one of teh holders that allows you to use the two "spare" corners of the CCMT inserts, as these are an obtuse angle they are a bit more durable and it allows you to get your monies worth out of the inserts, one always ready to go in a holder for the QCTP

For chunky iron castings I do have some similar CCMT 060208 again by Kennametal which are a bit more durable due to their 0.8mm tip radius though not much good on my machine for fine work

For parting in all metals I have a Glanze holder and thats still on their standard 2mm GTN tips. Have also recently bought one of the Mini-thin holders which are great for small grooves such as those needed for "E" clips Both in their own QCTP holders plus two other HSS parting tools

I also have a 6mm button type tool again from Glanze with the original bits but don't use it a lot

And for getting into tight spots I have a reversible L/H & R/H holder for the more pointed DCMT tips

Plus a load of HSS and some Brazed carbide only one R/H tool thats permanantly in an extended holder and ready to go, others used as needed

Unfortunately I can't quantify the finish like Andrew as I don't have a surface comparitor but here are a few shots to show what comes straight off teh tool.

Roughing EN8

And the ringlets of swarf from the 0.050" DOC, notice how they have been thrown away from the finished surface which I believe is a sign that the tip is working correctly

Bit of Ali done with a CCGT

Iron Casting done with 0.4mm radius CCMT

J

Edited By JasonB on 02/07/2014 13:35:57

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