# Carbide Tool Set for Mini Lathe?



## oskar (Apr 18, 2018)

I guess I was too fast and bought last month a “Boxed 5 Mini Lathe Tool Set 1/4" Indexing with 5 Carbide Tip Cutting Tools M9282” from England.

I understand now carbide tools are good for big machines which have the required power.

Can I use this set with my mini Taig lathe?


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## Billh50 (Apr 18, 2018)

I have used carbide tools on my mini-lathe for over 8yrs with no problem.


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## Ken from ontario (Apr 18, 2018)

You have heard a lot of good/ valid reasons why smaller less ridgid/less powerful lathes will perform better with HSS cutting tools but as long as you watch your depth of cut and speed/feed rate,lock the axis not in use (in order to have more rigidity during any operation), you'll do very well with that tool set.
But I'm just a hobbyist, you don't have to take my word for it, just wait and read the responses of all the smaller mini lathe owners and find out for yourself what they normally use, you'll be surprised how popular these tool sets are.
Not many  lathes can reach 5000 RPM and beyond., not everyone has those production type/ heavy machines but that never stops anyone from using carbide cutting tools.


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## oskar (Apr 18, 2018)

I’m also a hobbyist and don’t intent to take aggressive cuts. In addition I only work with aluminum (so far) and I’m happy to hear that carbide will work


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## Bob Korves (Apr 18, 2018)

Mini lathes lack power and rigidity.  Therefore they need tools that are sharp and cut easily.  Many/most carbide cutters are designed for 10+ HP lathes weighing 5,000 pounds or more.  For your mini lathe, what you need is sharp and positive rake, which presents the sharp edge directly to the work,, low friction and with an easy path for the chips to flow away from the cut.  It does not matter so much if it is HSS or carbide inserts or HSS inserts, what really matters is if it cuts the metal like butter.


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## mikey (Apr 19, 2018)

Oskar, you've gotten excellent comments here already. I just wanted to tell you that on these little lathes, carbide does not work nearly as well as a good HSS tool. You can use carbide; a lot of Taig users do and get along just fine but a good HSS tool will easily outperform them on your lathe. By that, I mean they will cut deeper, finish better and allow greater accuracy with fine cuts than carbide will. 

I own a Sherline lathe and know how the tooling impacts performance. On our tiny lathes we need all the help we can get and from long experience I can tell you that you will be better off learning to grind a good HSS tool. Use what you have to learn with but keep in mind that there are better options.


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## oskar (Aug 21, 2018)

I was planning to use this carbide tool set today but on close inspection I noticed the edge on the carbide is not sharp like an HSS tool, actually the cutting edge is kind of rounded.

Is this normal?


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## royesses (Aug 21, 2018)

I've purchased a couple of the 5 piece  1/4" carbide insert tool kits and all the inserts were rounded. I've been told that this is normal because very sharp carbide chips very easily. The carbide inserts work OK on the mini lathe but HSS inserts work much better. If you don't have a QCTP you'll need 1/16" shims to center the tool on the work.

Roy


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## oskar (Aug 21, 2018)

Thanks Roy I now understand and sound good. I do have HSS blanks and will grind my own but I got this set just to try the carbide. I also have a QCTP so I guess I have to adjust it as needed

Nicolas


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## royesses (Aug 21, 2018)

Nicolas it sounds as though you are prepared and ready to go. If you have any chatter or finish problems make sure your gibs are adjusted to eliminate as much looseness as possible and still have smooth motion in the carriage, cross slide and compound. I have a little bit of resistance to motion on mine (mini lathe)and use locks on the part that does not need to move.

Roy


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## oskar (Aug 22, 2018)

It’s true since I’m new to machining I often forget to adjust the gibs on the axes not used so thanks Roy for the reminder.

I will assume since the carbide is roundish at the cutting edge it will need more force to do the work so the gibs adjustment is more important. It will be a new experience for me.


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## SamI (Aug 22, 2018)

The radius at the cutting edge is denoted by the last two numbers of your insert identification number.  For instance one of the indexible tools I use on my mini lathe uses CCMT 060204 inserts.  The 04 means that the cutting tool has a 0.4mm radius.  You could try and source a smaller radius insert however in this instance the CCMT 060204's are probably the most widely available.

A larger radius will generally give a better surface finish but you are right in saying that it will require a greater cutting force.  Personally I have never found carbide inserts to be a problem on the mini lathe although I have never really used a lot of HSS tooling.  I do most of my turning in stainless steel which I found blunted HSS tooling too quickly and I was forever sharpening them.  This may well be due to poor tool geometry, poor grinding, improper feeds and speeds or any combination of the three!  For me the convenience of being able to switch out the cutting tip when it is worn led me to stick with carbide.


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## oskar (Aug 22, 2018)

SamI said:


> The radius at the cutting edge is denoted by the last two numbers of your insert identification number.  For instance one of the indexible tools I use on my mini lathe uses CCMT 060204 inserts.  The 04 means that the cutting tool has a 0.4mm radius.  You could try and source a smaller radius insert however in this instance the CCMT 060204's are probably the most widely available.
> 
> A larger radius will generally give a better surface finish but you are right in saying that it will require a greater cutting force.  Personally I have never found carbide inserts to be a problem on the mini lathe although I have never really used a lot of HSS tooling.  I do most of my turning in stainless steel which I found blunted HSS tooling too quickly and I was forever sharpening them.  This may well be due to poor tool geometry, poor grinding, improper feeds and speeds or any combination of the three!  For me the convenience of being able to switch out the cutting tip when it is worn led me to stick with carbide.



Very informative post, thanks Sami.

My set as shown in my post #1 came in a case and there is no info on the inserts except in the case it’s marked “5pc Index Carbide Turning Tool Holder Set 1/4” #M0136”. I got it thru eBay from a vendor in UK and perhaps it’s a cheap set but for a hobby user like me I would suspect its ok.

I have read about the index wheels some have (make) on their lathes but never understood what is the purpose of an “Indexible Tool” and how this is used. Eventually I guess I will learn that too.

So you turn SS with your mini lathe and I’m glad to hear that because I never thought a mini can handle SS however I assume with the proper tool and feed rates / RPM any material will be fine.


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## DiscoDan (Aug 22, 2018)

OK, people may not want to hear about Harbor Freight but they sell a set of 1/4" shank indexable carbide cutters for their own machines. I am actually using them on my 12x36 Craftsman in the original tool holder and they work pretty damn well.


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## homebrewed (Aug 22, 2018)

I use carbide insert cutting tools on my mini lathe and get decent results most of the time (but I'm my own customer and he's not so picky ).  

But if a good surface finish is important, a properly-sharpened HSS bit is the better choice.  Plus, you can grind the tool to optimize it for the material you're turning.


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## BaronJ (Aug 22, 2018)

Hi Oskar,

You have got some good feedback here.  I have, but rarely use carbide tool bits.  Stainless steel and cast Iron are probably the only exceptions. Most SS will work harden in an instant if you let a tool rub and cast iron has a hard tough skin as cast.  Carbide stands up well to these materials.

As for me, I have a small lathe and want a good finish with accurate cutting, so HSS does the business for me.


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## SamI (Aug 23, 2018)

oskar said:


> My set as shown in my post #1 came in a case and there is no info on the inserts except in the case it’s marked “5pc Index Carbide Turning Tool Holder Set 1/4” #M0136”. I got it thru eBay from a vendor in UK and perhaps it’s a cheap set but for a hobby user like me I would suspect its ok.
> 
> So you turn SS with your mini lathe and I’m glad to hear that because I never thought a mini can handle SS however I assume with the proper tool and feed rates / RPM any material will be fine.



Those look to be ISO inserts, I suspect TCMT's.  The ISO designation system allows you to work out what insert you have based on the shape, clearance angles and insert type.  It sounds confusing but it's really quite simple.  Have a look at the PDF here - there's a handy identification guide on page 6: https://www.slideshare.net/mx100/dijet-draaibeitelscnmg

If you can identify the inserts it means that you're not restricted as to where you can buy them whereas some hobby tooling suppliers don't tell you which inserts you need because then you'll have to go straight back to them to buy the replacements.  You'll probably end up paying high end prices for cheap imported carbide.  There's nowt wrong with cheap carbide in the home shop but if you can get them off of ebay for about £1 per insert then that's a whole lot better than £3-5 per insert! 

The mini lathe handles SS well for boring and OD turning.  As has been mentioned it does work harden and this can cause problems especially with worn cutting tools.  Grooving and parting however are a PITA!  I am lucky enough to have a 13 x 30" lathe that I usually use however it has been out of action for a few weeks so I've been using my mini lathe for this as well.  It can be done but it won't be an enjoyable experience!


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## BaronJ (Aug 23, 2018)

Hi Guys,

Just a quick safety note:  Carbide can shatter !  So eye protection is important.


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## Bobby Bailey (Aug 24, 2018)

www.latheinserts.com  has at their hobby lathe link, very small lathe friendly carbide tooling.


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## tcarrington (Aug 24, 2018)

I use the carbide insert tool bars for cast iron and steel. Most of the time I am hand working the surface to a polish afterwards, so any difference in the finish is not a big concern for me. Having the material come off easily is. The set I have came with HSS inserts which I will try on aluminum, but like Paris, I always have hand-ground HSS bits. (and in a variety of sizes).


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## macardoso (Aug 24, 2018)

Those indexable tools look like they took TCMT inserts.  Try out a TCGX ($5 each from Shars.com), they are ground to a sharp edge and polished for use on aluminum.  I have been able to get the to cut even when I am taking a <0.001" cut.  Really makes a difference

EDIT: Just a note, TCGX is the same shape as TCMT but with different edge treatment.  Mke sure the size matches up (TCMT *21.xx*) That bold part identifies the size of the insert. A TCGX will fit your tools.


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## homebrewed (Aug 24, 2018)

For me, choosing between $5 for a carbide insert vs. $1.30 for a regular-length 5/16" blank from Victor, I'd take the HSS.  They have a $25 minimum so there's an opportunity to get more stuff .  Cobalt blanks are still about 1/2 the cost of the insert.


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## BaronJ (Aug 24, 2018)

Hi Guys,

I agree !  I would grab them now since all this hooha with the tariffs is going to push prices up.  It has already started for some things.


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