Tool Geometries For Lathe & Mill Explained - Great Video Tutorial

[Rich V]

This is a very clear and informative video on tool geometries used for lathes and mills. Focus is on indexable tooling but the principles also apply to HSS tooling.

 

[RegisG]

Outstanding, even for us smaller machine guys. Reading chips at about 13-15 minute area has really helped my understanding of cutters.

Thank you,
Regis

 

[Bob Korves]

Good, informative video. Unfortunately, it can also give a novice viewer the idea that you need a PHD in cutter design and racks with thousands of tooling and insert choices. Bear in mind that all those choices are there to optimize manufacturing machining, and have little place in the home shop beyond understanding their principles to help get the best out of what you have. For us, if we need a special shape of tool, we can grind it from HSS. We can also standardize on one or a few insert and holders sizes and shapes that are versatile for our needs. There is a mountain of things to learn about all this, but the basics can help us choose wisely for our home shops. We can even use the tooling that has been superseded in industry, and is now available used and cheap. Just be very careful not to get tooling that requires too much power or rigidity for our smaller machines. A 8" negative rake face mill is not a good choice for a bench top mill, and a 1" shank insertable holder is going to be difficult to fit and power on your 9" lathe. Do some study before buying your tooling and make sure you understand what it is you are buying and how it will work for your needs. Also make sure you can still get useful inserts for any tooling you are contemplating. Some are very expensive or obsolete.

 

[LucknowKen]

Great video Thanx. Found this yesterday but when i went to re-watch it i could not remember the title.

 

[Tozguy]

Good, informative video. Unfortunately, it can also give a novice viewer the idea that you need a PHD in cutter design and racks with thousands of tooling and insert choices. Bear in mind that all those choices are there to optimize manufacturing machining, and have little place in the home shop beyond understanding their principles to help get the best out of what you have. For us, if we need a special shape of tool, we can grind it from HSS. We can also standardize on one or a few insert and holders sizes and shapes that are versatile for our needs.

Just to add that inserts can be ground too. I have been able to reclaim some chipped inserts by grinding to a different shape.

 

[Doubleeboy]

This post should be required watching for anyone starting out. Maybe the Mods could make this a sticky

 

[malmac]

I am just such a new person to machining and the video is terrific - the inclusion of diagrams articulate the exact meaning of terms that are often heard but rarely fully appreciated by my good self.
My current dilemma is working out what inserts and tool holders to purchase because my new lathe (which will arrive soon) uses 25mm tool holders - so all new tooling is in the firing line -
but which tool holders?
Which tips?
Which brand?
Can I get tool holders which will allow me to experiment with more than one TC tip design, in terms of chip breaking design, roughing Vs finishing and the list of questions roll on.

There is much to learn and sorting out a priority for what comes before what is also quite a task. It is needlessly expensive to just buy tooling on a whim and then find it is rarely if ever used.
So getting to terms with this is taking quite a bit of my time at present.

Thanks for sharing.

Mal

 

[Wreck™Wreck]

Do you mean 25 MM square shank tools or fixed diameter round tools? Please explain.

Most manufacturers of insert tooling have inserts for specific materials/cutting conditions and applications, roughing or finishing, OD/ID grooving, face grooving, internal undercutting, threading, parting, boring, profiling and form turning.

A lathe that will hold 25MM tools is a large machine for a hobbyist, I often run a 600MM/850MM through the gap swing X 2540MM between centers lathe, the tool post will hold a maximum 31MM tool. One may always use a smaller shank tool with appropriate bushings or spacers or mill the shank of a larger tool.



Good Luck

 

[malmac]

yes I mean 25mmx25mm shank tooling.

The lathe I have ordered is only 625mm between centres - smaller to fit in my workshop than a longer bed.

I understand the swing (in the gap) on the new lathe will be around 23 inches/ 585mm - so fairly large for a hobby machinist.
Swing over the bed 400mm and over the cross slide 246mm - but at present these are quoted figures not measured - so we will see.

I hear what you are saying about the different tips and tools available - yes.
However sorting through the options when you consider brands and tool holder shapes and sizes are just over whelming to start with.

For instance with brands - Walter (one supplier I could use) or maybe Kyocera or Seco or something else????
Then if we take just straight turning and facing as a pair.
What is a good tool holder (which would need to come in right and left variations) that is well enough optioned to that I could fit a range of TC inserts
for roughing (stainless, mild steel, cast iron and aluminium)?
Then I would want tips for finishing the above materials as well. Admittedly I could grind tools for aluminium but the others I feel I get more consistent results from carbide tips.
So the holder might be a 85 degree diamond so I can turn and face in the one quick change tool.
But maybe that is not the best starting point. I do accept quite readily that there are many tooling options and no tool will do everything - BUT what to start with as a good compromise.
I am probably more inclined to look at flexibility of a tool rather than a one tool, one job approach - most of my tasks are one offs so there is a lot of head scratching to work out a way of using what I have to get to what I want to do.

So that just deals with straight turning and facing - there is boring and parting just to mention two obvious others.

I downloaded some of the links you have posted and it re-enforces just how little I know. Thank you.

Mal

 

[Tony Wells]

The majority of my turning is done with a 80° diamond insert, a CNMG-43x. If you get the holder with a negative 5°lead, you can use it for turning and facing without changing anything. Inserts are available in a wide variety of grades and coatings and are relatively inexpensive. For roughing, a larger nose radius is generally more desirable than for finishing, so a -432 I use for roughing and a -431 for finishing. If I have a profile that will not allow the use of that 80° insert, I stay with a diamond, but use a 55° diamond, a DNMG-432 or 1, depending on roughing or finishing.

I'd go with one of the majors like Sandvik or Kennametal on the holder. Parts do wear out, and the bigger companies will support their product a long time. On a common insert like those I described, you can choose from any number of manufacturers. And shop for deals.

For boring, I still stick with a 80° diamond when possible. Larger bars can use the same inserts as the OD holders many times. The changes in rake, etc are in the pocket and or the seat that comes with the bar. Smaller bars are available that hold a diamond insert also, just not the very common 432.

Parting and grooving are a different family group, and I have my personal preferences, but I'll let someone else chime in on those.