[Mike1000]

Hi. I could need some advice from you gurus in here on how to use my lathe cutting tools properly. I am a beginner when it comes to using a lathe! I have a Sieg lathe and some lathe tools that I purchased from Little Machine Shop as well as the red Chinese cutting tools that came with the machine.

I have so many tools that I don't know what tool to use. How do I select tools properly for normal lathe operations?

What I intend to do is to turn down some alu rod to make axles of proper diameter for small stepper motor projects and hobby robotic projects. I also want to turn down some plastic material for making knobs etc.

I have some fairly basic questions:

See images of the lathe tools that I have at hand (click for larger size).




Q1) Is it better to use the A1, B1, C1, D1, E1 style cutting tools than the red ones (A-J) that came with the machine?

Are the ones with the exchangeable cutting tips better than the red ones?

I have read that the carbide material in the tips of the red tools is not of a good quality. Someone told me that he used the triangle ones that are exchangeable.


Q2) What are the correct use of A1, B1, C1 style tools? What are the different angles for? What angle is the correct one for different lathe operations?


Q3)How do I properly angle the A1, B1, C1 style tools for turning down an alu rod?

Q4) Can you describe the typical uses of the red tools? For example, what is the tool A for? I guess tool B is for threading. I guess tool C is for cutting. What about D and E and F as well as G and H? (Click image to magnify)


Q5) How do I avoid that the tool is grabbing the material I am trying to turn down?

Q6) Do I need to (can I) grind / sharpen the triangle shaped cutting tools?

[Al_The_Man]

In the mean time, pick up a copy of How to Run a lathe by the South Bend lathe Works, it is an old book and although it does not cover insert tooling, there is a lot of basic information for the beginner.
They can be had on Ebay fairly cheap.
Al.

[txcncman]

A1) Inserted tools are generally better because: they usually have built in chip breaker geometry and when the insert is worn or broken, it can be replaced. Carbide comes in different grades (tough versus hard). We have no idea which grade(s) of carbide you have on your tools. Any grade of carbide can usually cut aluminum reliably.

A2) The A1 and C1 tools are intended to cut to square shoulders. The machining technique used with these tools tends to be less aggressive on depths of cut and feed rates and takes more fineness than the B1 and D1 tools. This has to do with part of the tool geometry called lead in angle.

A3) You set/change the angle of the tool by changing the angle of the tool post.

A4) Almost all brazed carbide tools are intended to be custom ground at some point either for resharpening or for your particular needs. Tool A is basically a blank that can be ground for any needed geometry. Tool B appears to be a 90 degree neutral tool. Tool C is a groove/shallow part off tool. Tools I and J are intended to be used as boring tools.

A5) No clue what you mean by the tool "grabbing" the material. Are you getting chatter? Maybe your work holding or tool holding is not rigid enough. Maybe the machine itself is not rigid enough for the depth of cuts you are attempting.

A6) Since the inserted tools usually have built in chip breaker geometry, they cannot usually be resharpened/reground reliably and any regrinding destroys the indexable use of the insert.

Finally, there are dozens of videos on YouTube that you can watch to help you visualize how lathe turning operations work.

[Mike1000]

Hi! Thanks for answering. It generated several very basic questions ...

A1) Inserted tools are generally better because: they usually have built in chip breaker geometry and when the insert is worn or broken, it can be replaced. Carbide comes in different grades (tough versus hard). We have no idea which grade(s) of carbide you have on your tools. Any grade of carbide can usually cut aluminum reliably.

Do you mean by inserted tool, the triangle shaped cutting bits with a screw in them?

A2) The A1 and C1 tools are intended to cut to square shoulders. The machining technique used with these tools tends to be less aggressive on depths of cut and feed rates and takes more fineness than the B1 and D1 tools. This has to do with part of the tool geometry called lead in angle.

I don't see what is the difference between A1 / C1 and B1 / D1 apart from the angle of the triangle.

How do you set up the tool to cut a square shoulder? There are three edges. Two of them looks like they can be used to cut with. What edge do you use to cut a square shoulder with? How do you angle the tool?


Are there three edges so you can turn the inserted triangle when one side of it is worn out?

A3) You set/change the angle of the tool by changing the angle of the tool post.

I see. However what side of the tool do I cut with?

A4) Almost all brazed carbide tools are intended to be custom ground at some point either for resharpening or for your particular needs. Tool A is basically a blank that can be ground for any needed geometry. Tool B appears to be a 90 degree neutral tool. Tool C is a groove/shallow part off tool. Tools I and J are intended to be used as boring tools.

OK. However the tools I have appear unsharp. They don't cut properly in a steel bolt I needed to take down the diameter of. It appeared that it only rubbed the surface even if I tried to apply force to cut. Do I need to sharpen / hone those? On plastic materials like POM it appears like they work.

A6) Since the inserted tools usually have built in chip breaker geometry, they cannot usually be resharpened/reground reliably and any regrinding destroys the indexable use of the insert.

What is a chip breaker geometry? How does it work?

[txcncman]

Yes. The inserted tools are the ones with the screws that hold the inserts in place.

A1 and B1 are right hand tools. C1 and D1 are left hand tools.

I must answer all of your remaining questions with a question. Did you search for and watch any of the YouTube videos on lathe turning operations?

Examples:

[ame=http://www.youtube.com/watch?v=J63dZsw7Ia4]1.3 Machine Tool Basics -- Lathe Cutting Tools -- SMITHY GRANITE 3-in-1 - YouTube[/ame] <<<<Lathe cutting tool basics

[ame=http://www.youtube.com/watch?v=OeN1etkFsbk]Metal Lathe basic turning - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=ReeRv4iAEEo]Harbor Freight 7 x 10 Mini Metal Lathe Video 3 of 3 - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=IDKJjDlCGhU]Manual Lathe Instructional Video - YouTube[/ame]

[ame=http://www.youtube.com/watch?v=Mn9jpqI8rao]Single Point Cutting Tool Geometry - YouTube[/ame]

After you search and watch about 50 of these types of videos, please come back and ask all the questions you need to.

[2_many_hobbies]

I recommendatory you watch A LOT of youtube videos. I got my lathe two years ago and it took my a year of hobby use to cut any more than the most basic profiles. I can now do stainless to around 0.003" accuracy but It took a lot of practice.

#1 is to learn how to actually setup your tool co they cut cleanly. If the tip of the insert it above or below centre you will get chatter and other issues. Setup in a pain in the but, but when skipped or overlooked it can ruin your day.



Here is what I used to learn what tool is for what. Your insert tools (those triangles are inserts) are tools #1,2,4,6,7.

[Mike1000]

In the mean time, pick up a copy of How to Run a lathe by the South Bend lathe Works, it is an old book and although it does not cover insert tooling, there is a lot of basic information for the beginner.
They can be had on Ebay fairly cheap.
Al.

Hi Al. Thanks for the tip. I found a scanned copy of another South Bend publication online How to Grind Lathe Tools
Even if it is a grinding tutorial it had pictures of typical usage of different tools.

I also found this library at W.E. Williams WEWilliams - South Bend Lathe Library

I think my red tools appear unsharp when I try to cut with them. Do I need grind them sharp?

[Analias]

In the mean time, pick up a copy of How to Run a lathe by the South Bend lathe Works, it is an old book and although it does not cover insert tooling, there is a lot of basic information for the beginner.
They can be had on Ebay fairly cheap.
Al.

Al, is this the book you are referring to? It's available on Google books for free:

https://play.google.com/store/books/...kFBQUFZQUFKIl0.

[neilw20]

Digging in?
Once the stiffness of the machine/toolholder/job allows deflection of more than the chip thickness it is self perpetuating and something will give.
It can dig in because the tool moves,
the job is not clamped well enough or flexes,
the tool post moves due to backlash,
the RPM drops but the feed stays constant (in dist/time),
a chip builds up on the tool and changes tool geometry,
coolant chills the chip and it hardens increasing HP and kill RPM.
Any of the above, and more and lack of experience, which is gained as the stuff ups (sometimes) reduce.

[691175002]

I personally wouldn't use any of the tools you pictured in your post. The 5/7 piece triangle holder sets contain a lot of holders that are not useful and the inserts they come with are garbage.

High quality aluminium inserts are literally so sharp that you can cut yourself accidentally by picking them up. The inserts you have would have trouble cutting through sheet of paper without excessive force.

Learn to grind your own tools, it will always be useful. If you want indexable tooling get something decent:
tools tooling for hobby lathes

I do 90% of my turning with a SCLCR holder as per the link. If you need left hand turn it upside down and put the lathe in reverse.