Carbide Tool Set for Mini Lathe?

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.
 
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.
 
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.
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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.
 
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.
 
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 :D).

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.
 
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.
 
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.
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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!
 
Hi Guys,

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