Which Carbide Lathe Tools?

[MarkSParticipant @idriver]

Hi Guy’s,

I now have my new lathe (DB10VS) and mill (Seig SX3.5) setup. The lathe came with a set of HSS cutting tools and I added some carbide tip boring tools. During my first few test pieces I really liked the ease with which the boring tools cut the metal and have decided that I want to go down the route of using carbide tipped tools for general turning on the lathe which will take 12mm tooling once I fit the QCTP.

What a bewildering array of tools and tips there are though!

Is there a recommended general make or type of tip I should start with for some standard turning and facing of mild steel?

Thanks.

[JasonBModerator @jasonb]

I have tried to standardise on the CCMT and CCGT inserts as these can be used in boring bars as well as turning tools. A right handed holder for these will do both turning along teh length as well as facing when the holder is mounted at right angles to the lathe axis and would be my suggestion for trying them out.

I have used mostly the Glanze brand sold by Chronos for the last 15yrs and they seem perfectly adequate. Sods law they are not listing a 12mm one which probably indicate sout of stock but this is the 10mm one, I would suggest even at 12 mm that you use the 06 size inserts as it keeps the cost down, my preference is a CCGT 060202 which is the bright polished (sharper) insert with a small 0.2mm tip radius and they will work on ALL metals we are likely to use.

Add other holders such as left hand and ones that use the obtuse two “spare” corners of the inserts if you get on OK with the righthand one.

Inserts from APT, they do them in two’s for hobby use or boxes of ten once you have decided what you like to use

[John HaineParticipant @johnhaine32865]

12mm seems large for a smallish lathe. Id suggest standardising on 10mm.

[Nigel Graham 2Participant @nigelgraham2]

The bewildering variety of inserts is due to they being made for high-rate machining of all sorts of shapes in all sorts of metals. The intention in industry is that you use the right tip for the material as well as the form being cut, and the tips’ commercial lives are often quoted by their own manufacturers in a few tens of minutes!

Although I am not convinced by the arguments that carbide tips have to be used at high speeds on our modest machine-tools because they can be to meet commercial production rates.

The arcane mix of letters and numbers encodes the tip shape, size, material and profile.

 

I do use both HSS and carbide – almost all bought from J.B. Cutting Tools – but mainly carbide tips for screw-cutting only because the angles are fully correct. Sometimes it is easier to obtain a better finsih on steel with a properly-ground HSS turning tool than with carbide, but it depends a lot on the material, depth of cut and feed. And is a lot cheaper – carbide costs brass!

 

Thread-cutting using insert tooling:

The standard screw-cutting tips do not normally give the true, rounded roots and crests; so if you go in to the “book” depth for the tip’s apex the result will be shallow. So I normally cut to that depth and finish the thread to size and shape with a die; sometimes turning a little “book” root-diameter spigot on the end as a guide.

(Studs are sometimes left with that little spigot anyway, as thread-protector and assembly aid.)

 

[Nigel Graham 2]

On Nigel Graham 2 Said:

 

 

Thread-cutting using insert tooling:

 

The standard screw-cutting tips do not normally give the true, rounded roots and crests; so if you go in to the “book” depth for the tip’s apex the result will be shallow. So I normally cut to that depth and finish the thread to size and shape with a die; sometimes turning a little “book” root-diameter spigot on the end as a guide.

(Studs are sometimes left with that little spigot anyway, as thread-protector and assembly aid.)

 

The standard is generally a “full Form” insert which has all the correct radii and wil “top” the thread. It is the “partial form” inserts that cover a range of pitches that won’t form the correct radii and need the depth adjusting.

Just down to the user what they buy but as many model engineers have deep pockets they don’t tend to use full form as much preferring one insert that may come close to what several full forms would do.

[Julie AnnParticipant @julieann]

I prefer to use full form inserts. Saves faffing about; starting with nominal diameter material one just cuts to the theorectical thread depth, give or take a thou, and job done. The roots and, more importantly, the crests are fully formed. So no need to mess about deburring the crests. When the crest is ‘just’ beginning to get cut that is a good indication that the thread depth is correct.

Be aware that external and internal threading inserts have different profiles as per thread specifications.

Julie

[old martParticipant @oldmart]

For 12mm square tooling, I would recommend starting with CCMT 06 for steel, CCGT 06 finishing steel and non ferrous, they use the same holder. And DCMT 07 for steel and DCGT 07 for finishing steel and non ferrous which also share a holder. There are several sizes of boring bar which also use these inserts.

If you want to try small quantities of inserts rather than buying a whole box which turn out to be unsuitable, then APT will sell them to hobbyists at a slightly greater unit price which allows experimentation. APT also sell threading inserts singly. I can recommend buying from them.

The cheap Chinese inserts made today are better quality that they used to be.

[BazyleParticipant @bazyle]

“general turning on the lathe which will take 12mm tooling once I fit the QCTP.”

As JH implied it is not about shoving in the biggest you possibly can. For a 5in centre height lathe 1/4″ is enough and 3/8″ when you need long reach. Big tools just get in the way.

[VicParticipant @vic]

I’ve only got one 12mm Toolholder, this type, it works well. This is a pretty good deal at the moment, Tool Holder + 10 inserts. You can get replacement inserts on eBay and Amazon for around £10 for a box of ten. Even cheaper if you don’t mind waiting a week or so for delivery from abroad.

[old martParticipant @oldmart]

I didn’t expect to see a 12mm square toolholder made for DCMT 11 size inserts, they are more at home in 16mm and larger fittings. DCMT 11 and DCGT 11 are our favourites in 20mm toolholders.

The Smart & Brown model A toolroom lathes are only 9 X 20, so the working radius is only 4 1/2″, but they were originally intended to take 3/4″ square tooling.

[JasonB]

On JasonB Said:

I have tried to standardise on the CCMT and CCGT inserts as these can be used in boring bars as well as turning tools. A right handed holder for these will do both turning along teh length as well as facing when the holder is mounted at right angles to the lathe axis and would be my suggestion for trying them out.

I have used mostly the Glanze brand sold by Chronos for the last 15yrs and they seem perfectly adequate. Sods law they are not listing a 12mm one which probably indicate sout of stock but this is the 10mm one, I would suggest even at 12 mm that you use the 06 size inserts as it keeps the cost down, my preference is a CCGT 060202 which is the bright polished (sharper) insert with a small 0.2mm tip radius and they will work on ALL metals we are likely to use.

Add other holders such as left hand and ones that use the obtuse two “spare” corners of the inserts if you get on OK with the righthand one.

Inserts from APT, they do them in two’s for hobby use or boxes of ten once you have decided what you like to use

Thank you for the great reply. That gives me a lot to go on moving forward.

[Howard LewisParticipant @howardlewis46836]

One of the advantages of using a 8 or 10 mm tool shank is that the CCMT0604 inserts are common with 6 and 8 mm boring tools reducing the cost and space of tip stock holding.

Howard

 

[JasonBModerator @jasonb]

The 12mm shank Glanze that I linked to takes the smaller 06 inserts. Maybe as they are aimed at hobby users they all have the small size even the 16mm sq shank ones.If you click on the chart that is one of the photos you can see the actual holder codes the SCLCR 1212F06 where the last two numbers are the insert size.

This is quite an easy to follow guide to what all the letters and numbers mean so you can check.

[DiogenesParticipant @diogenes]

If Glanze are O/S, and you need one ‘in hand’ to physically check heights & clearances for your new toolpost support, RDG supply a 12×12 for -06.

 

[SillyOldDufferModerator @sillyoldduffer]

The limited range of holders and inserts sold by ArcEuro are of suitable size and shape for machines that aren’t industrially rigid, speedy or powerful.   A newcomer won’t go far wrong with them!

A trick! The sharp uncoated inserts industry run flat-out on non-ferrous metals work well on steel at our slower cut rates. The “Sumitomo CCGT 060204 NAG-H1 Carbide Insert (Non-Ferrous)” is an example.   Try it.

Carbide inserts have many advantages over HSS in industry.  Carbide can be run much hotter than HSS, and is able to remove metal five to ten times faster.  They are also precision matched to optimise cutting – shaped to suit particular alloys, finish, with and without chip breakers and other refinements.  Unfortunately, not only does this makes them difficult to understand and buy, but many inserts are unsuitable in our context!  Industry have production engineers, specialist apps and consultancy : amateurs have to play join the dots, and are liable to buy unsuitable ‘bargains’ off the web!.  (Such as the disposable inserts made with low carbide content to suit certain industrial processes and are easily broken if applied incorrectly.)

Don’t dismiss HSS out of hand, advantages include:

• can be resharpened many times (not necessarily cheap – needs a grinder and skills!)
• well-suited to small machine speeds, especially older models
• easier to produce a good finish.  (Less of a problem on a lathe with full electronic speed control because RPM is easily tweaked for best results.  Carbide may not work well at any of the fixed speeds available on a belt driven lathe.)
• can be shaped into form tools – very valuable when needed!

Don’t jump too quickly to conclusions!  That carbide boring tools worked well may have been more luck than judgement!   Be prepared to change if a tool doesn’t perform acceptably.   There’s a lot to learn.  What works best for you will emerge over the next few years.

Dave

[VicParticipant @vic]

I agree about HSS Dave. Before I stopped working I considered the cost of carbide inserts and decided to try Tangential tooling as a cheap cost effective alternative. I use mine a lot.

One thing that’s changed in recent years though is that if you look beyond traditional suppliers, the cost of inserts has come down considerably. I started with the DCGT07 inserts, bought from Jenny (along with a double sided holder) at one of the shows many years ago. The inserts at the time (and still now from some suppliers) was about £20 a box of ten. With only two cutting tips this works out at £1 a tip. These particular inserts weren’t very durable and prompted me at the time to try out Tangential tooling. Moving on I happened to notice that many inserts were roughly the same price even though they may have many more cutting tips. I’ve not tried the source yet, but if your total order is over £15 ( easily done 😆) I can get a box of ten inserts giving me 60 cutting tips for under £4. This works out at under 7p a tip, or 14 times cheaper, a considerable difference.

This isn’t to dismiss some traditional suppliers, I noticed the other day that APT had some of their own tool holders on discount for just £15.

[Chris12Participant @chris12]

I have been using https://www.engineeringsupplies.co.uk/ to get the holder and the inserts and been pretty happy with it (surprised no one seems to use them on this site).

And I’ve mostly been using the ccmt 060202. It works well for mild steel and brass.

[bernard towersParticipant @bernardtowers37738]

Dont forget J B cutting tools

[bernard towers]

On bernard towers Said:

Dont forget J B cutting tools

Yes, I purchased a very nice (1.5mm) insert parting tool from Jenny at the Midlands Show last year, following an impressive demonstration of one by a gentleman on the SMEE stand (I’m sorry, can’t remember your name but thank you for your advice).

It works very well in my elderly Myford S7 and cuts small diameter steel parts very cleanly and without chatter. Saves me having to set up my large (rear-mounted) parting tool for the work.

Regards,

 

IanT

[bernard towers]

On bernard towers Said:

Dont forget J B cutting tools

I mentioned Jenny earlier. Whilst JB may still offer good prices at the shows? Online they are no longer cost effective for me.

[VicParticipant @vic]

I just got this offer through.

 

And was wondering if they will also work on my End Mill? Many years ago I bought the Little Hogger set from Chronos. I had to stop using it for a while as they didn’t have replacement inserts. I then started using TNMG inserts for turning and couldn’t help noticing that they were the same size as the inserts for my mill. A quick test proved they worked very well for this unintended use. Much cheaper too. Chronos only seem to sell sets of three different inserts for the Little Hogger but I only generally use this one.

[old martParticipant @oldmart]

The Little Hogger indexable endmill would not be happy with TNMG  inserts, they are more likely to use TCMG type which look similar but are single sided with a 7 degree clearance angle wheras the TNMG are double sided with zero clearance, the sides are square, 90 degrees. The sides of the cutout for the insert are angled to match the 7 degrees, so the bottom of the cutout is smaller, I cannot understand how you got the TNMG’s to even come close to fitting.

Users of HSS tooling have a legitimate reason to use a QCTP as the height changes every time they are sharpened, at the museum, we have at least 60 tools using carbide inserts, all at exactly the same height, so we don’t need to worry about tool heights and both lathes share the same tooling. Only boring bars have shims, kept in the box with the bar. Having 60 or more QC toolholders would be pretty expensive and take up a lot of room.

[old mart]

On old mart Said:

The Little Hogger indexable endmill would not be happy with TNMG  inserts, they are more likely to use TCMG type which look similar but are single sided with a 7 degree clearance angle wheras the TNMG are double sided with zero clearance, the sides are square, 90 degrees. The sides of the cutout for the insert are angled to match the 7 degrees, so the bottom of the cutout is smaller, I cannot understand how you got the TNMG’s to even come close to fitting.

Users of HSS tooling have a legitimate reason to use a QCTP as the height changes every time they are sharpened, at the museum, we have at least 60 tools using carbide inserts, all at exactly the same height, so we don’t need to worry about tool heights and both lathes share the same tooling. Only boring bars have shims, kept in the box with the bar. Having 60 or more QC toolholders would be pretty expensive and take up a lot of room.

I’m sorry to disappoint but I am using TNMG inserts (as in the picture) in my little Hogger and it works well. I’ve only tried steel cutting inserts so far but I’ll try the polished ones for aluminium at some point.

[old martParticipant @oldmart]

It is very unusual for a milling holder like yours to use negative inserts by design. I have got some TNMG 16 inserts in aluminium grade and they work well. I don’t think those discounted inserts would be any good for milling, the cutting edge is much too limited, the cutting edge only extends half of the side. I bought a box of very similar and found they would be more useful in a big lathe which could cut most of the depth of the cutting edge per pass, say 6mm depth of cut. I tried sharpening n edge with a diamond wheel and the insert cut aluminium quite well, but they will not be likely to get much use.

[JasonBModerator @jasonb]

The Triangular little hogger inserts do not have any clearance angle. And as for the pocket that looks as though it opens out towards the bottom, certainly NOT angled to match a 7deg edge. So I can understand Vic getting on OK with TNMG.

The angled outwards pocket means the neutral edge insert locates against it’s side a sthe pocket is a little shallower than the insert’s thickness and also means you don’t risk damage to the actual cutting edge on the back side by trying to seat it down into a 90deg internal corner.

The cheapies he shows will be fine too provided the vertical depth of cut does not exceed the cutting edge. Note that the pocket geometry makes them unsuitable for milling a vertical edge, really only for flat surfaces.

TNMA is the most likely code as there is no CSK on the hole.

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