CNMG toolholder styles

Hello all, long time viewer, very infrequent poster.

I'm posting a thread to ask for opinions on a common CNMG OD holder. I use left hand typically for heavy roughing anything on my CNC lathes. Right or left hand, the last letter would designate the hand of the holder.

I've attached pics of the three most common that I'm aware of for CNMG 4xx, 5xx, and 6xx series inserts. I'm curious about a type that I've never used. And that is #1 in the list.

1-PCLNL or PCLNR
The insert is clamped similar to the old Kennametal Kenloc's with the LP cam pins. But the old Kenloc's also had a top clamp. I'm most interested in this newer style, because less chance for a chip to get tangled around the clamp, and coolant doesn't have anything in it's way to the insert. I've never used this type of holder, and the type I created the post for.

2-DCLNL or DCLNR
The insert is clamped and drawn back into it's pocket with one screw. I use these, about 20-25 holder's currently. Really like them because it's easy to explain to an employee what is needed to index an insert. Downside I have found that the top clamps and carbide shims , and carbide shim screw can become so expensive that a new holder is more economical then replacing parts.

3-MCLNL or MCLNR
The most common, with a center locating screw and a top clamp.

The pics I've attached should be in order. I'm really looking for opinions on the first description. I have never used this type. (PCLNL) I've seen them in videos, and they seem to usually have bigger CNMG 543/544 or 643/644 inserts in them. I use mostly WNMG or CNMG 43x for roughing so I'm also looking at this style for a WNMG. Wondering if they repeat reasonably on an index, I would never use this style other then roughing.

Thanks for any opinions. The 2nd and 3rd type I'm very familiar with. For those that use the first type, what are your thoughts about them?

Lathe tool-holder designations ...

On the mill turn machines I always used PCLNR holders and never had any problems. But we also only did light to medium roughing on those machines.

I use MCLN. I do not like DCLN and never tried PCLN.

I've used all three and standardized on the DCLNR after extensive testing in a specific application. I tested on 2-1/8" hex with a CNMG 432, 316SS, turning at 2.09" diameter (.182" d.o.c. to the corners, keep the nose of the insert in the cut), 380sfm, .01 ipr. The DCLNR holder had 30% better tool life than the MCLNR holder. The PCLNR holder wasn't even close, and shifted in the pocket a couple times.

I think, for light roughing, the PCLNR would be okay...just didn't work in my application. The DCLNR does have a disadvantage with coolant delivery because of the large clamp, but holding power is much better than the M and P.

For a future test, I plan to try high pressure coolant holders with precision coolant ports (I'm using Capto and have LNS ChipBlaster pumps). But, the high pressure holders tend to be of the PCLNR type. I need to adjust the cutting parameters for this holder to take advantage of the higher speed possibility and likely drop the feed so the insert doesn't move in the pocket. I need to find out which one gives me more productivity.

D style tool holders are by far the best clamping style as they hold the insert down, and pull it into the corner.

M's are a pain in the ass when the eccentric jams, and P's are only useful when you need the extra chip clearance for boring bars.

There's basically no price premium to the D or P anymore. I can get Sandvik stick holders for $110 CAD in any style.

bradleyk said:

I've used all three and standardized on the DCLNR after extensive testing in a specific application. I tested on 2-1/8" hex with a CNMG 432, 316SS, turning at 2.09" diameter (.182" d.o.c. to the corners, keep the nose of the insert in the cut), 380sfm, .01 ipr. The DCLNR holder had 30% better tool life than the MCLNR holder. The PCLNR holder wasn't even close, and shifted in the pocket a couple times.

I think, for light roughing, the PCLNR would be okay...just didn't work in my application. The DCLNR does have a disadvantage with coolant delivery because of the large clamp, but holding power is much better than the M and P.

For a future test, I plan to try high pressure coolant holders with precision coolant ports (I'm using Capto and have LNS ChipBlaster pumps). But, the high pressure holders tend to be of the PCLNR type. I need to adjust the cutting parameters for this holder to take advantage of the higher speed possibility and likely drop the feed so the insert doesn't move in the pocket. I need to find out which one gives me more productivity.

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I have done a bunch of testing with the HP coolant style and settled on SECO or Walter depending upon availability. They are D clamps. They make both stick and capto I have both and 1k psi on both. Massive improvements

lever clamps suck, kennametal is apparently R&D‘ing D style, they like Sandvik only make garbage lever ones so far.

ManualEd said:

M's are a pain in the ass when the eccentric jams,

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That's easily solved by using another allen wrench from the bottom of the eccentric.

ManualEd said:

M's are a pain in the ass when the eccentric jams,

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This happens and is a source for lots of repairs which we love as a 5 minute fix.
It is done by those who do not understand how to tighten a M toolholder.
I actually get paid over $100 per hour to do classes in this at big shops. Seco/Carboloy and Sandvik offer the same service.

CarbideBob said:

This happens and is a source for lots of repairs which we love as a 5 minute fix.
It is done by those who do not understand how to tighten a M toolholder.
I actually get paid over $100 per hour to do classes in this at big shops. Seco/Carboloy and Sandvik offer the same service.

Click to expand...

So what's the correct way to tighten an M holder?

ManualEd said:

D style tool holders are by far the best clamping style as they hold the insert down, and pull it into the corner.

M's are a pain in the ass when the eccentric jams, and P's are only useful when you need the extra chip clearance for boring bars.

There's basically no price premium to the D or P anymore. I can get Sandvik stick holders for $110 CAD in any style.

Click to expand...

Good price, where are you buying them?