My WM280 is often sold as an 11×28 lathe and I tend to use 8mm and 10mm shank holders and they seem fine with normal amounts of stickout.

That lets me use CCMT and CCGT 06 inserts for turning and boring except for my largest boring bar which needs an 09 insert.

SCLCR gets used most of the time and with the shank set across the lathe axis it can turn dia and also face without having to be touched, The left hand SCLCL does not get used much only on the odd occasion.

I also have both the holders that use the other two corners which are often used for roughing and working on castings as the obtuse 100deg corner is a bit more robust.

If your machine is old, it may not be fast or rigid enough to make the best use of carbide tooling. But that is not to say that it can't be used successfully on an older machine.

Carbide was developed for industry to maximise the rate of metal removal, and sometimes does not work too well at low speeds, feeds and shallow cuts.

My experiences.

However low speeds and feeds with lubrication have produced some fine finishes for me.

CCMT0604 tips are the ones most often used on my 6" centre height lathe.

(Carbide for Roughing, Boring, some screwcutting, and Radiusing . SUPERB on hardened materials. Red hot swarf off case hardened materials! Does NOT like intermittent cuts,tends to chip )

But work well on milling cutters.

A "Diamond" (HSS ) tool for finishing and fine cuts (Can do 0.0005" or less cuts when freshly sharpened. ) Carbide tips are not sharp if you examine them closely, unless the ground type, so better suited to deeper cuts…

Intermittent lubrication on a heavily loaded carbide tip can cause cracking, so is mostly used dry in the hobby sphere. Carbide tips do wear, though.

I use HSS and carbide, depending on what is being done. HSS withstands my accidentally banging the tool, where carbide does not, so is cheaper for the clumsy. like me.

Also, I can regrind HSS at the week end when the stores are closed, or when a non standard form is needed.

So horses for courses!

Howard

Or contact JB Cutting Tools who sell good products and could probably advise.

I recommend that you start off with the smaller size, and later you may consider to add the larger to your collection. You can get a range of boring bar sizes which all use the 06 size, and your lathe can probably even hold 20mm ones as the tool height is actually nearer 10mm, about half of the holder size. Check out the APT website, although they are mostly catering for industrial users, they helpfully will sell carbide inserts singly from a range which home users find useful. The inserts are more expensive singly, but if you are not sure what works best for you and want to try a range of different grades then it makes sense to avoid buying a box of ten of the same. WNMG06 is a trigonic insert with 6 cutting edges which is available in steel, stainless, and aluminium grades and can be used in toolholders down to 16mm which might be a future thought.

I use CCGT09T304, which are meant to be used for ally on steel, using HSS speeds and feeds.

Push the feed and the tip will go.

Stall it in the job and the tip will go.

So they will all chip equally well if you are clumsy with them

They are no more nor less robust than any other size turning tool unless you include milling cutters which are much tougher. The 04 is the tip radius and means semi finishing, as in gives a decent finish but not as strong as an 08 rougher

Positive inserts commonly are fitted in the toolholder horizontally and most have a 7 degree angle at the tip to give clearance and usually a chipbreaker to enhance the sharpness. Negative inserts are usually double sided, so the face of the insert must be square to the top and bottom. To work, the whole insert is tipped down at an angle of 7 degrees in line with the centre and the tip. Because there are usually some sort of chipberakers moulded in to the surface, the negative inserts are not that different from positive inserts when in use, and the grades for aluminium are pretty much equal to positive inserts.

 There are various charts which show the different types.

https://www.mitsubishicarbide.com/en/technical_information/tec_turning_tools/tec_turning_insert/tec_turning_guide/tec_turning_identification

Edited By old mart on 01/12/2021 20:44:55