Thread: Insert tooling beginner question

Hi all

I am looking for some advice on lathe insert tooling. I have an Emco super 11 and so far use HSS tooling via an eccentric engineering diamond tool holder. This has been a good setup but I’d like to have a play with some insert tooling.

My projects are varied and I have turned stainless, brass, mild steel and also want to do some titanium. I have read a fair bit about inserts and understand the limitations of a home workshop sized lathe like mine. I am tossing up between DCMT and CCMT inserts as these seem to be regularly recommended to home workshop users like myself. I believe the DCMT will bit a little more fragile but may be better suited to slightly less finer cuts and finishing. I am happy to take my time and experiment with feeds, speeds and inserts to get to desired performance. I will also be getting a round insert tool which I think will work well on the Ti with some careful use.

So any particular thoughts on DCMT versus CCMT for general workshop use?

thanks in advance
Ian

Size is not so much the issue as is rigidity and power.

There is probably not much in it between a DCMT and a CCMT insert if you are just experimenting. I use CCMT's because they fit both my boring bars and LH/RH tools. With the tip angle being greater, I'd like to think they are a little sturdier, but that is more likely wishful thinking on my part.

Michael

I have recently just done exactly what you’re planning to do. After a lot of research I went down the CCMT path And I’m pretty happy with the decision. I have a mix of the standard inserts (CCMT09T304) and also the ground ones (CCGT09T304) for aluminium. One thing I have noted is that you can’t sneak up on your dimensions like you can with HSS, particularly with the non-ground inserts. You really have to hog off quite a bit of material and hit your dimension was taking quite a big cut still.

The polished inserts on aluminium however leave a fantastic finish almost every time and how much cut you’re taking.

I upgraded my motor and pulleys on my lathe just before I went to inserts and so now it has plenty of hp to take big cuts, but if I hadn’t have done that I am not sure my flat belted lathe would’ve had the ability to use the inserts properly.

I can see why people say start with HSS, I’ve only really just got good enough with my lathe after a few years using it to properly justify going to inserts I think.

I’ve used CCMT and DCMT successfully on Ti. I haven’t tried a round insert.

No comment on CCMT vs DCMT. Both are good, I'm sure - I use CCMT, and I think I have almost all the variety of toolholders sold for them, and possibly one or two that aren't! Never tried DCMT, but I could see the pointier nose being useful sometimes. I think both inserts are very widely available, just compare what's out there in the particular size you're after, and that might help decide. I don't reckon you could go far wrong with either really.

Just don't forget - the wide angle corners work too, so buy or make holders to use them. One of my holders presents the CCMT with the edge at 45 degrees to the spindle axis (convenient chamfering built in!), and is set up to use the pointy tip for facing, and the wide tip for turning. I kill more tips turning than facing, due to it being the majority of the work, so I set up that way deliberately. If I kill the wide tip, I can still chuck that insert in a regular SCLCR holder, or a boring bar. If I kill the narrow tip, I have another tool (can be bought, have to look up the number though) that uses the wide tip but doesn't face that I tend to use on interrupted cuts. Although since making the 45 degree tool, probably won't use it so much since it's more or less the same thing, but without the convenience of the 45 degree edge. Maybe I'll have to make one of those facemills that uses that tip - or another boring bar holder to use it.

But on the round insert, I'd nix it personally... I have one, pretty horrendous thing to use. Loves to chatter like crazy when the length of edge engagement gets up there, and doesn't really work that well on lighter cuts either - A CCMT with an 08 nose radius works far better. Of course, just my opinion.

CCMT for general work, DCMT when you need to get close to a live centre in the tailstock, CCGT/DCGT for soft materials (ally, brass, plastic)

0.4mm corner radius for general use, 0.2mm for light cuts, 0.8mm if you need to remove a lot of material

For the best finish in steel, the depth of cut should be at least equal to the corner radius, so if your lathe isn't super powerful, stick to 0.2.

Plenty of good info above for you to make your choice. I have an H&F 336 lathe (300mm by1000mm) and went with the ccmt inserts, 0.2 nose radius. Purchased a set of holders with inserts off ebay. The holders were OK and still using them but the inserts were useless, would chip within one or two passes. Bought some better inserts and they cut and last well. So make sure you get good inserts what ever style you go with. I get mine from MZG on aliexpress but you are looking at around a two month wait for shipping at the minute. I'm happy to buy inserts from China as long as the manufacturer puts their own name on them, in my opinion a non Chinese "quality brand name insert" on aliexpress at cheap prices screams fake.
Others may chip in with a good local source for inserts.

Thank you everyone with the excellent information. One other question is around insert size. If I go with CCMT inserts for instance what would drive me toward CCMT06 versus say CCMT09?

Good point re inserts. Oddly enough I bought cheap ones to get started with and the CCMG have been exceptional and the CCMT, whilst not setting the world alight on surface finish on all metals (I have some mystery steel in my piles), they’ve held up brilliantly with some very aggressive cuts. I have chipped one already but with the boring bar, not facing or turning.

Can share the seller on eBay if people are interested.

Originally Posted by Danger Mouse

Thank you everyone with the excellent information. One other question is around insert size. If I go with CCMT inserts for instance what would drive me toward CCMT06 versus say CCMT09?

Depends on the the size tool that the tool post can accommodate. Tool holders with a 12mm shank will generally use 06 inserts while 16mm holders take 09

I use 09 on my 9” Hercus and I reckon they’re the perfect size. Bought some 06 by mistake and had to get the tool holder for them too. They’re good for fine work but most of my work is done with 09’s.

If your lathe can use 16mm holders - CCMT09 holders tend to come in 16mm shank and up - definitely use the bigger inserts. If you poke around you will find holders that use the big corner for turning facing and boring.

Originally Posted by Danger Mouse

Thank you everyone with the excellent information. One other question is around insert size. If I go with CCMT inserts for instance what would drive me toward CCMT06 versus say CCMT09?

Thanks guys, I’m using 12mm tooling and can buy holders for either the 06 or 09 size so that was why I was asking. I guess it sounds like it won’t matter too much. Any real negative of using 09 with 12mm tooling?

Originally Posted by Danger Mouse

Thanks guys, I’m using 12mm tooling and can buy holders for either the 06 or 09 size so that was why I was asking. I guess it sounds like it won’t matter too much. Any real negative of using 09 with 12mm tooling?

I don’t think so. I use 12mm tooling.

If you will be boring small bores and wish to use inserts you would be better off with 06 inserts, and then interchange these with your turning tools.
You may find that 09's may be a little cheaper than 06's.
With the majority of home workshop lathes you won't be able to utilise the full cutting ability of either of these tips.
In my case I use 06 the majority of the time for boring and turning.