Parting accident

[JohnFParticipant @johnf59703]

Plus one for Graham & Howards observations, I cannot see definitively but you should also ensure the top slide is not extended.

Personally I do not like parting tool holders of the design you are using, they de-crease rigidity due to increased overhang, a real problem on smaller machines and although yours appears to be a more robust machine it will still have an effect.   Your tool post looks to be a Dickson style in which case I would look for a parting tool holder dedicated to your tool post similar to :-

John

[peak4Participant @peak4]

Note that JohnF’s photo above shows the sloping side for holding a tapered blade vertically.
Not all of the cheaper ones have that feature; some omit it intentionally.
Also have a read of this thread; I added quite a lot of photos of different style holders; The holders are mostly OK, but less so the photos.

Parting tool blade not sitting square

Bill

[VicParticipant @vic]

I suspect many of us would like this!? 😆

[Graham MeekParticipant @grahammeek88282]

While the tool above is very lovely, and many of us would aspire to owning one. There comes a problem when using such tools in the home workshop. After all they are intended primarily for industry. Many of the smaller machines are of an age now where they were designed around HSS tooling. These machines will never work an insert to its capacity and in all probability the insert will suffer for this and have a short life span.

Although I now use an Emco Compact 5. The parting blade on my Emco Maximat Super 11 was only 2 mm wide and HSS. This machine would regularly part off 30 mm FCMS at 600 RPM with no problems at all. Of the box of 10 blades purchased with the machine in 1986, 8 of them went with the machine in 2022, and that machine saw a lot of work. The Compact 5 uses 1.5 mm wide blades and regularly parts off 16 mm FCMS at 550 RPM, (just as an example).

Most of the insert parting tools I have used in my career have been 3 mm wide. This width starts to become a problem on a not so rigid hobby machine. Plus if I have a dozen 9 mm long components to make then every third component I have lost one in swarf. Given todays prices it is something that needs to be taken into account especially if those components are Brass or Bronze.

From experience most insert tooling is purchased to avoid the re-sharpening of a HSS tool. Because most newcomers struggle with this. I know because as a newcomer myself 56 years ago, I too struggled, but like a lot of things in life it is a challenge which needs to be overcome. Especially if you intend a life in industry as I did. Not all bosses are keen on you getting new tools from stores. When a simple regrind will extend the life of the existing tool.

That is not to say I don’t use insert tooling. Much of the time I use inserts to remove a lot of metal, but finish off with HSS. There is an exception to this in that one insert I use for aluminium, brass and plastics gives a better finish than HSS.

Before someone tells me changing and insert is quicker than regrinding, yes I know. In industry this matters, but in the home workshop we are supposed to be doing this for pleasure and learning new techniques along the way. Without the pressure of clock watching.

Regrinding tools is another of those facets, (excuse the pun), in engineering that needs to be mastered, like screw cutting and taper turning. There are times when the hole you need to bore is not covered by a standard tool. Do you say it cannot be done, or do you step up to the plate and grind a tool to suit?

Regards

Gray,

[Howard LewisParticipant @howardlewis46836]

Graham is absolutely right.

There will come a time when a particular tool, not in the “standards” is needed. A tool of a particular form, perhaps., such as a special chamfer or radius

You won’t be able to grind a carbide insert, so HSS has to be way to go.

I am a fan of Tangential Turning Tools (But use carbide inserts for roughing or boring, or on hardened materials, but for most turning and facing jobs this is what is used. There is only one face to grind, and in terms of cost ,is extremely economical.  The cost of a HSS toolbit is about the same as one carbide insert, but can be reground many times. My Tangential Turning Tool dates from before 2019, and I am only on my second short piece of 1/4″ HSS toolbit, which is not yet worn out by any means.

I can take cuts with it from 0.050″ down to 0.0005″. Carbide does not work well with tiny cuts, or withstand the occasional accidental bang. I do not get on with brazed carbides, they seem to chip more easily than inserts.

And I don’t have to worry much about dropping a small retaining screw into the swarf!

My 3/32″ x 1″parting blade is over 30 years old, (And second hand when given to me) and not worn out yet. It has been used in a rear toolpost on a second hand Myford ML7, and has now been on a shop made, 4 way indexing rear post, for 20 years. It is mounted inverted, on centre height, and has no top rake.

A 2mm inserted parting tool, in the front 4 way toolpost had so many dig ins that the holder eventually distorted and is now useless.

As an Apprentice, we were taught how to grind knife and other tools, and soon learned what could be a “jack of all trades” or needed to be ground specifically for a particular material.

You can regrind HSS at 9 pm on a Saturday night, when no one is open to sell you a replacement tip!

For most work, a suitably ground HSS tool suffices.  Carbide comes into its own when the workpiece is hardened, or work hardens, or when needing to cut a thread form accurately.

Purely my experience, others will be different

Howard

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