DCMT vs TCMT inserts for low power mini lathe

[Mach_Zero]

Hey everyone! Eventually I'll get a bigger lathe, but for now I have one of the super cheap 7 x 14" mini lathes. It gets the job done (barely), but it really struggles even on mild steel.

I have the most basic set of 1/4" TCMT inserts and they seem to work ok. They have the standard 1/64" nose radius.

I was thinking about getting a set of DCMT tool holders and inserts since the sharper diamond shape should reduce tool pressure slightly.

Am I correct with this assumption? Is there a better option or will it be pretty much the same thing?

 

[Aukai]

It is my understanding that the small lathes do better with ground HSS tooling. There is a bunch of pages giving directions on how to grind your own. The first few pages have a lot of how to do it.

Models for grinding HSS Lathe Tools

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/threads/lathe-accessories-tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing...

www.hobby-machinist.com

 

[ttabbal]

Those inserts are about the same in tool forces. HSS would be preferred, but if you really just can't deal with them, look for inserts designed for aluminum. They are sharper and honed from the factory. The shape isn't too important for general work, they all get the job done. Sometimes the shapes and angles work better in tight spaces etc.. The aluminum inserts will be easier to break, but can handle steel and most other materials without issue.

That said, I still prefer HSS most of the time. I can get them at least as sharp and they are far more durable. I won't say I never use carbide, but most of my general turning is done with HSS.

 

[Ken from ontario]

I mainly turn brass, copper and Aluminum with my mini lathe,

TCGT110204-AK H01/ TCGT21.51-AK carbide insert turning blade Use for Aluminum | eBay

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My personal favorite:

10pcs Korloy DCGT070204-AK H01 DCGT21.51-AK H01 Aluminum Cutting Inserts | eBay

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[Mach_Zero]

It is my understanding that the small lathes do better with ground HSS tooling. There is a bunch of pages giving directions on how to grind your own. The first few pages have a lot of how to do it.

Models for grinding HSS Lathe Tools

In a recent thread by @Darkbluesky, http://www.hobby-machinist.com/threads/lathe-accessories-tools-ideas-of-what-to-buy.62043/#post-511618, @ttabbal joked about sending me blanks to be ground into lathe tools ... he was joking! But it got me to thinking ... yeah, I know it's not a good thing...

www.hobby-machinist.com

I've heard that before and I do have some HSS that I've ground. I used to be really good at grinding HSS when I did more machining in high school and undergrad. But I just wanted carbide for the convenience (more like laziness). I'll check out that thread and see if I can learn a bit more about grinding HSS for mini lathes. Thanks!

I mainly turn brass, copper and Aluminum with my mini lathe,

TCGT110204-AK H01/ TCGT21.51-AK carbide insert turning blade Use for Aluminum | eBay

Find many great new & used options and get the best deals for TCGT110204-AK H01/ TCGT21.51-AK carbide insert turning blade Use for Aluminum at the best online prices at eBay! Free shipping for many products!

www.ebay.ca

My personal favorite:

10pcs Korloy DCGT070204-AK H01 DCGT21.51-AK H01 Aluminum Cutting Inserts | eBay

Find many great new & used options and get the best deals for 10pcs Korloy DCGT070204-AK H01 DCGT21.51-AK H01 Aluminum Cutting Inserts at the best online prices at eBay! Free shipping for many products!

www.ebay.ca

I mostly do aluminum, but I want the capability to turn steel for parts that require the strength. Those inserts look pretty good. I know my lathe can take tool holders up to 1/2". I was thinking of investing in a set of 1/2" tool holders for the 3/8" inserts (as opposed to the 1/4" inscribed circle inserts that I currently have). The reason is so that I can still use those in the future when I do upgrade to a slightly larger lathe. Do you think it's worth it?

Something like this (but maybe for triangle inserts instead): https://www.ebay.com/itm/1634796407...uid=iyhL28KbSFu&widget_ver=artemis&media=COPY

 

[Ken from ontario]

For me 10mm or 3/8" holders works the best, I don't think I own any 1/2" tool holder ( I might, I'll have to check) but a good rule of thumb is to stay within the sizes that your lathe performs the best & gives you the least amount of trouble.

 

[doj53]

This Australian guy (Artisan Makes) does great work on a 7x14 mini lathe.
I suggest that you take a look at his YT videos and in particular this one -

where he compares HSS vs Carbide tooling including TCMT and DCMT inserts.
He does seem to favour the DCMT inserts.

 

[Mach_Zero]

For me 10mm or 3/8" holders works the best, I don't think I own any 1/2" tool holder ( I might, I'll have to check) but a good rule of thumb is to stay within the sizes that your lathe performs the best & gives you the least amount of trouble.

Yeah my quick change tool post is supposed to work with up to 12mm tool holders (which would hold 3/8" inserts). So I think I should go with that. It will also make the setup a tiny bit more rigid since I'm currently using the 10mm tool holders. I know most of the rigidity problems are with the compounds and cross slide, but maybe it'll have a small impact.

This Australian guy (Artisan Makes) does great work on a 7x14 mini lathe.
I suggest that you take a look at his YT videos and in particular this one -

where he compares HSS vs Carbide tooling including TCMT and DCMT inserts.
He does seem to favour the DCMT inserts.

I've actually seen that video and regularly watch his stuff. I think his video probably was one of the things that got me looking into other options. I still wanted more options from experienced hobby machinists and see how much of a difference there really is.

I'm kinda leaning towards going with a set of triangle insert tool holders and getting some inserts for aluminum. But I can't find a decent set of TXXX tool holders with left hand, right hand, and boring bar turning tools of 12mm shank size. I'll keep looking.

 

[pontiac428]

I save the inserts for material that needs it. The rest of the time, well, let's just say that grinding HSS is like teaching a man to fish and feeding him for a lifetime. Why buy inserts for $5 each, when I have a bunch of broken HSS drill bits to grind? It's practically free.

 

[DavidR8]

Hmm at 11:25 he says that HSS is the way to go on a mini lathe.
I agree with him. Even on my South Bend 10K a sharp HSS tool allows greater depth of cut and a cleaner finish than import carbide. I have invested in some more expensive inserts and they can make a difference on challenging materials. That said the inserts are also $12 each so I am very careful with them.