How to use a turning tool

[NoviceParticipant @novice]

Hi all,

The other day I was given a turning tool of Sanvik brand with the following code on it: PTGNR 1212 F11. There were also some inserts called TNMG 11 03 02.

I can find specifications, but that does not make sense to me.

It's so different from my SCLCR type. What can I do with it? Have not tried it yet.

Very curious for your comments.

Jan

[NoviceParticipant @novice]

[Grizzly bearParticipant @grizzlybear]

Hi Novice,

Picture please.

Regards, Bear..

[JasonBModerator @jasonb]

Looks just like a right hand turning tool to me ( goes from right to left)

Image

J

Edited By JasonB on 19/12/2013 18:32:18

[nigel jones 5Participant @nigeljones5]

like Jason says……

[DMBParticipant @dmb]

JasonB,
You must be having a laugh – over 60 quid for a lathe tool?

[JasonBModerator @jasonb]

Not bothered about the price I just put up the first image that Google gave me as someone wanted to know what it looked like and did not even look at teh price.

But its about the going rate for that style of industrial holder, Seco, Kennametal, Hertel are all withing a pound or two

[Richard Wright 1Participant @richardwright1]

Well Novice,

I was a sales engineer and industrial cutting tool research engineer once upon a time and indeed it is for conventional right to left machining.

The gold colour is titanium nitride coating, very thin but what most people don't realise is that when it gets black it is still there improving the cutting action. It actually soaks back into the carbide substrate so don't chuck blackened ones away!

Unfortunately, tungsten carbide has the worst cutting edge of all tool materials i.e. microscopically it has a large radius compared to the best; diamond. Then from top (diamond) down: polycrystaline diamond, cermets, ceramics, silver steel,HSS….

TC Tungsten Carbide relies on high speed and HEAT to 'cut' so only really useful for heavy duty. Don't cool it with splashes of coolant either! Either FULL flood coolant or NON or you will introduce micro-cracking and ruin your tool!

HSS cutting tools and milling cutters tool-life can be increased 10 fold by dipping into liquid nitrogen over-night. Tested this myself scientifically.

Don't use pure diamonds or composite diamond tips on anything containing Carbon or you will ruin the diamond as it itself is composed of carbon under high pressures etc.

Use Cubic Boron Nitride to machine anything including TC at 80 Rockwell C! Use high speed, high pressure though until a swarf comes off red hot (400 M/min cutting speed; 0.1mm/rev feed) on hard steels and even hardened shafts and welds etc!

If you can't afford all these expensive 'exotic' tools, use good old HSS carefully ground (constant dipping to avoid softening while grinding) To achieve an excellent finish on steel parts, make a scrapper tool of HSS; normal looking right to left but with a flat at the front parallel with the lathe axis. Final scrape cut a few microns at a slow speed (feed less tha the width of the flat so get overlaps) for an excellent result.

Hope I've helped a bit?

Richard

[Richard Wright 1Participant @richardwright1]

**LINK**

[joegibParticipant @joegib]

Posted by Novice on 19/12/2013 17:21:06:

What can I do with it?

(1) Place it in a finely-carved rosewood box, velvet lined.

(2) Apply inscription — "In loving memory of Western mass manufacturing".

(3) Secure item in your bank deposit box together with your Faberge eggs and whatnot..

It's obviously a precious jewel, not a rather mundane engineering artefact.

Joe

Edited By joegib on 20/12/2013 08:25:09

[Oompa LumpaParticipant @oompalumpa34302]

Posted by Richard Wright 1 on 19/12/2013 21:55:34:

**LINK**

Thank you for that, most informative. I have just bought my first "Indexing Cutter" and I am interested to know as much as I can about them.

HSS is cheap, convenient and easily formed, but sometimes you can't help but be seduced by the promises made of "lndexable" tooling.

graham.

[DMBParticipant @dmb]

Richard,

Thank you for your input, very useful.

JasonB,

I understand and agree with your post. However, my point is that for most model engineering, HSS is adequate and el cheapo.

John.

[Douglas JohnstonParticipant @douglasjohnston98463]

Just popping down to the supermarket for a gallon of liquid nitrogen. What is the science behind this observation, Richard ?

Doug

[NoviceParticipant @novice]

Hi all. At first I wish you a a proporus and healthy 2014.

Sorry for my late reaction, but I have been away for a couple of weeks.

As asked, herewith twoo photo´s of the tool. It was given with 6 inserts so much cheaper than HSS. I knoe it is a right hand tool and I have not ordered a rosewood box yet, because there are things I want to know first.

Is there a special reason fot the tilted insert and a rake of zero of the insert. This puzzels me because I only know of straight holders and inserts with a rake . I wonder how this message is getting on. I think I made a sort of mess of it. Hope for your reactions. Jan

I

[MuzzerParticipant @muzzer]

It's tilted like that to get all 6 corners usable. The top rake is built into the insert. Some inserts have only a one-sided insert with 3 usable corners and the insert sit flat.

I get pretty good results and very pleasing removal rates with my indexable tools (mainly CCMT inserts which are single sided diamond shaped ones). There are different inserts for aluminium which are worth getting. If you get the cutting speed and depth of cut high enough the swarf breaks up as it comes off (this is how they are supposed to be operated). You get a better surface finish if you take a decent cut, so very fine finishing cuts are actually counterproductive.

I'm sure you get lots of opinions both ways here but used properly(!) they have distinct benefits even for the home user.

Muzzer

[NoviceParticipant @novice]

Hi John,

I understand this one is not useable on my S7?

Jan

[Terence Yates 1Participant @terenceyates1]

Hello all, I have to use replaceable tipped tools as I am on Oxygen and the sparks from grinding HSS sets my oxygen mask on fire. In fact it can be very dificult being a model engineer if you are disabled.

Terry.

[Richard Wright 1Participant @richardwright1]

I may be wrong but I think you may be able to get HSS tips for the holder.? Contact Sandvik or similar company. Richard

[MuzzerParticipant @muzzer]

Posted by Bogstandard2 on 09/01/2014 16:50:40:

Unlike HSS, carbon steel, brazed tungsten tipped or ground replaceable tips, normal ones like you have work in a different way, as they don't have sharp edges, they don't 'cut' the material as such, and without going into very technical detail, they sort of change the molecular structure at the cutting face and delaminate the material from what is being cut, as they rely on pressure and speed (plus the power to do it) rather than a sharp cutting edge.

So unless you have a machine that can give you that power speed and pressure, you just might not find the results very good.

If you only have a smallish lathe, I would suggest you put it away safely until at some later stage, a larger lathe might come your way.

That all sounds rather mysterious but apart from the fact that the cutting edge usually is very slightly bevelled to improve life and make it less liable to breakage, the cutting process within the workpiece is pretty much the same, with a same shear zone and chip formation etc. The additional power required by having this slightly blunter tip isn't a great deal in our applications. I've seen some suggestions that it actually reduces the tool forces.

My Bantam only has a 1.1kW (1.5HP) motor and much of my machining is done some way below this – I can see that from the motor current displayed on the VFD. As for finish, take a look at the results I achieved in this photo I took recently (from one of my albums). This is carbon steel C1025 (similar to silver steel) and the final cut wasn't heavy compared to what I was using during roughing cuts – but not so light that it messed up the finish. I'm pretty happy with it and didn't need to go near it with emery paper – that's how it comes out.

As I said, there are different inserts for light alloys. Apart from the silver coloured non-stick coating, the cutting angles are better suited and an excellent finish can be achieved without requiring a heavy cut.

The main downside of taking shallower and slower cuts (if you have to) is that the swarf doesn't always break up and you can get long spirals of hot, blue swarf flying off. You can always interrupt the feed to break them – or stand safely back!

Get some decent inserts (Sandvik, Korloy, Iscar etc) and give it a go, find out where they are useful. I doubt you'll be disappointed. It's good fun!

Muzzer

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