Lathe tool types

[Gene PavlovskyParticipant @genepavlovsky]

Thanks so much, everyone. This thread is now full of helpful advice and links.

I like this giant lathe tool model in the video

I did read a couple of lathe books and a lot of articles, so I have basic understanding of the terms and processes (and kinds of tools available), but no hands-on lathe experience whatsoever.

My lathe came with some 20+ carbide-tipped tools (brazed tips, not indexable), and I was recommended by an acquaintance to not bother with either these or HSS tooling, and just get a set of indexable carbide tools. However before trying these out, I do want to learn to do things the old-school way and learn tool grinding as well. As Howard mentioned, this is good for beginner to get tool grinding skills, and with a lot of practice, this should lead to a better understanding the choice of shapes and angles for different materials, directions of cut etc. And from what I gather, even those who use indexable carbide tools, still have to sometimes grind HSS tools for special occasions. I think I will start with trying to grind a general purpose RH tool. Any other tools I should look into making next?

[Gene PavlovskyParticipant @genepavlovsky]

Posted by Bazyle on 04/05/2020 20:59:30:

Gene, the tools with chip breakers just look like they have fine points which will be a bit more delicate. If you do some searches on lathe tool shapes you will find the roughing tools are shaped to avoid a fine point so are tougher but don't give a good finish. That doesn't matter when roughing. You then switch to the nice sharp tool for the detail work.

Perhaps if you can measure the angle on the sharp one it woul dgive us a clue, though it might just be intended fro doing fine detail.

Bazyle, this set from Paulimot has a tool that looks like #4 in my set, and the description for it is "gebogener Schruppdrehstahl zum Längsdrehen", translated as "curved roughing lathe tool for longitudinal turning". A very similar looking tool in ARC's set is described as Chamfer tool. This set from Soba calls it Corner tool. Very confusing, possibly all of these cheap HSS tools are made in the same factory in China, can't manufacturers/distributors even agree on what is a certain tool shape for?

The included top face angle of #3 tool in my set is around 39 degrees, so it's very pointy and I suppose delicate. Finishing facing tool, perhaps? Or for making V-shaped grooves (what would those be useful for, decoration)?

[Ketan SwaliParticipant @ketanswali79440]

Gene,

The descriptions provided by ARC are given after consultation with end users in the U.K. and U.S.A.

Sets made by or offered by the links you have given are of their own choosing, made out of their own thinking, or what they have been told by their buyers around the world, or no thinking.

These products are made in India as well as in China.

Perhaps you should read a book like this I am sure you can get it from an Amazon near you.

When you work with HSS, please do not presume that you are doing it 'the old way'. It is the correct way to learn. HSS is more forgiving for beginners than Carbide. Many beginners loose interest in the hobby after breaking carbide tools…. quickly.

Ketan at ARC.

Edited By Ketan Swali on 05/05/2020 08:48:45

[Gene PavlovskyParticipant @genepavlovsky]

Thanks Ketan. Good to know how these descriptions are written

I do have the book you mentioned, I've bought all of Harold Hall's books in this series, I like his writing style. I haven't got around to read it yet, thinking that I should focus on the Lathework course first. I already read it, next step is to re-read it while actually doing all the projects. But perhaps I should first read the chapter on lathe cutters in the sharpening book. I don't think I will be able to make the grinding rest like in the book yet, I do have a Veritas (a woodworking tools company) grinder tool rest which could probably be adapted to the task. I also found this compilation of articles advocating free-hand grinding without a toolrest, want to give this a try as well.

Edited By Gene Pavlovsky on 05/05/2020 09:59:17

[SillyOldDufferModerator @sillyoldduffer]

Posted by Gene Pavlovsky on 05/05/2020 08:12:57:

…

I did read a couple of lathe books and a lot of articles, so I have basic understanding of the terms and processes (and kinds of tools available), but no hands-on lathe experience whatsoever.

My lathe came with some 20+ carbide-tipped tools (brazed tips, not indexable), and I was recommended by an acquaintance to not bother with either these or HSS tooling, and just get a set of indexable carbide tools.

…even those who use indexable carbide tools, still have to sometimes grind HSS tools for special occasions. I think I will start with trying to grind a general purpose RH tool. Any other tools I should look into making next?

Well, I'm going to recommend tackling the 'no hands-on lathe experience whatsoever' problem, before moving on to grinding HSS.

For a beginner the advantage of a set like your is that the tools are sharp and correctly shaped. Self-taught beginners face a steep learning curve:

1. Understanding the machine's controls, adjustments and limitations (which might include faults)
2. Selecting an appropriate tool shape and setting its cutting point to centre height while minimising overhang.
3. Work-holding: short stubby is easy, long slender is hard, as are odd unbalanced shapes.
4. Understanding materials. Metals vary considerably and many are downright difficult to machine.
5. Finding a reasonable combination of rpm, feed-rate, and depth-of-cut for the job in hand.

As all of these can result in disappointing results, it's best to eliminate as many unknowns as possible during the learning phase. So, don't start with home-ground HSS, have a go with the left and right hand cranked knives. The RH knife is good for facing, LH for most ordinary turning. Of the set, these are likely to be most popular. Get hold of a machinable Aluminium Alloy or Brass Rod about 20 – 30mm diameter and do some experimental turning and facing. Not scrap!!! Steel can be used, but keep to EN1A / 1113, ideally Leaded. It it doesn't go well, time to ask why, but at least you know the tool is good.

Not unknown for inexperienced chaps to assume their new machine is carp, and send it back or dismantle it, when the real problem is they are untrained, unpractised rookies. When I started with a mini-lathe I suffered months of poor results because my scrap box happened to be full of inappropriate metals.

Once the beginner gets reasonable results, or understands what's wrong, then it's time to branch out. If a home-ground LH knife fails to cut properly when the set version does, then you know it's the home grind that's wrong. The set LH & RH knives are easy to sharpen – a simple straight grind across the end face.

HSS is your oyster once the grinding wheel is mastered! Any tool shape you like – see Mick B1's examples earlier in the post. But beware of chaps claiming grinding is easy! Like anything else, some take to grinding like a duck to water. Others find it difficult; after a lot of practice I get acceptable results, but I'm far from Mick's standard. The only way to find out is to try it!

Re mystery tools, the very sharp one is a finishing tool. The Chamfer/Corner tool is dual-purpose – held straight it cuts chamfers, held at an angle it reaches into corners. In practice, the operator is allowed to improvise, for example I've used the sharp finish tool to botch a 55° thread. Mick goes even further – having found a set didn't meet his needs, he reground the tools into other shapes. It's allowed!

For what it's worth, I prefer the convenience of carbide inserts to HSS but it's not a religion. I switch between HSS and carbide happily, depending on the job. I agree with your advisor's recommendation to avoided brazed carbide. The sets often arrive unsharpened, and they require a special grinding wheel. I'm sure brazed carbide is useful for certain work, but if I'm grinding for a precision job I'd rather use HSS, otherwise inserts are quick, easy and hard working.

Have fun!

Dave

[JasonBModerator @jasonb]

Posted by Gene Pavlovsky on 05/05/2020 08:34:24:

Bazyle, this set from Paulimot has a tool that looks like #4 in my set, and the description for it is "gebogener Schruppdrehstahl zum Längsdrehen", translated as "curved roughing lathe tool for longitudinal turning". A very similar looking tool in ARC's set is described as Chamfer tool. This set from Soba calls it Corner tool. Very confusing, possibly all of these cheap HSS tools are made in the same factory in China, can't manufacturers/distributors even agree on what is a certain tool shape for?

As the saying goes it's not the tool that you have but what you do with it!

Sketch shows tool No4 being used to both take roughing cuts along the workpiece and also chamfering the corner

[Gene PavlovskyParticipant @genepavlovsky]

Thanks for a nice detailed comment Duffer. It's very thoughtful and indeed I wanted to eliminate one set of unknowns by having a reference tool which is expected to work out of the box. I did, though, get confused by your description of what LH and RH tools are used for (you mentioned "The RH knife is good for facing, LH for most ordinary turning&quot. I was under the impression that most ordinary turning is done from right to left (towards the chuck), so wouldn't that be a RH knife such as this one? The definitions for LH/RH were suggested earlier in the thread: RH tool being one suitable to turn towards the chuck, LH one towards the tailstock. The roughing/chamfer tool sketch from Jason being a RH one. Please correct me if I'm wrong.

[duncan webster 1Participant @duncanwebster1]

Try a tangent toolholder, very easy to sharpen the tools, the bit if HSS last a very long time as you're only making it a bit shorter each time. I use mine a lot, here's one you can make yourself, **LINK**

or you can buy one from Eccentric Engineering if you have deep pockets **LINK**

[Ronald MorrisonParticipant @ronaldmorrison29248]

I rarely use a left hand tool in my lathe. About the only time I find it necessary is if I need to turn a piece with a smaller diameter in the middle and then I use it to cut toward the tailstock end to clean up the cut. Most other operations work well with the right hand cutters.

Many of the carbide tool are not as sharp as can be had with HSS as the carbide, while harder, is usually more brittle and easily chipped. For light cuts on a small lathe you can use a diamond hand stone to put a sharper edge on them but be careful not to chip them then.

[Gene PavlovskyParticipant @genepavlovsky]

Duncan, thanks, this looks very interesting indeed. I will start with regular style of tools and later will try a tangential toolholder. I had Mike's entire website already downloaded as there are a lot of interesting projects there!

Ronald, I do have a set of large diamond stones (usually for woodworking tools and knives), as well as hand-held diamond sharpeners, so I might try honing the carbide-tipped tools I have to just see how they differ from HSS in the way they cut.

[JasonBModerator @jasonb]

I do believe Dave (silly old whatsit) has got his left and right hands mixed up as the cranked RH tool you have is as shown in yesterdays sketch best suited to turning down the diameter of work and not facing.

If it were an insert tool then the geometry of the insert will allow a RH tool to both turn and face without altering the position of the tool.

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