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lathe tool selection

bdrmachine

Aluminum
Joined
Mar 21, 2017
This question is for all you guys that should have PH D’s in machine application science by understanding the cryptic world of lathe tool selection: I purchased a Romi C420 cnc lathe with an 8 position turret. I now need to select 1-inch tool holders. I’m starting to decode some of the strange numbering assigned to the holders and carbide inserts. As a low budget job shop (more hobby than job at this point) I would like holders that will give me the most bang for the buck, machining a wide array of different metal types. Would a cnmg insert with its negative rank perform well on aluminum and steel? Any suggestions?

Thanks
Brian
 
Would a cnmg insert with its negative rank perform well on aluminum and steel?

Stop hanging out on the home shop board.. How the insert sits in the pocket does not dictate the
cutting geometry that the material sees..

I suggest not filling your head with all the tool holder designations.. I don't have a clue what
NLQPRZ stuff is, and I don't want to know... I got enough shit to think about... Besides that is
why we have salesman, guys we can lean on that know this stuff.

You pick up the phone and you say "Hey, Curtis" I need some 1" stick holders, 2 CNxx 43x, 2 DNxx 43x,
a VCxx 32x, a laydown threader, and something to part off with. And shows up on your doorstep in a
couple of days, and it won't be crap, and you'll like the price.

I say VCxx because VNxx don't repeat for shit, and the insert selection kind of sucks... I only use
them when I'm absolutely desperate. And I say the laydown threaders, because Top Notch stuff has
gotten mad expensive, and I don't think its as good..

I vote for C's over W's, because W's are harder to get your hands on, the insert selection isn't as
large, can't take a stupid depth of cut, and they don't sit in the pocket all that well.. When
you add all that up, the 2 extra corners don't pencil out.

The next question is.. Left handers or right handers... I vote for left handers.
 
Would a cnmg insert with its negative rank perform well on aluminum and steel? Any suggestions?
Brian

There is a CNMG holder that has never even been put in a drawer let alone taken out of the machine. On the rare-rare occasion that I need something with more back clearance (VNMG or DNMG) I put one in next to the CNMG, not replace it. Point is I use it every single day. So YES.

Different materials, cutting conditions, radii all to be determined by the insert. As Bob said the orientation of the insert pocket doesn't determine the contact with the work piece. The first letter in the CNMG sequence is the shape C,V,D are the most used then W,S and R.


Robert
 
The next question is.. Left handers or right handers... I vote for left handers.[/QUOTE]

Whatever hand directs the cutting forces into the bed, not trying to lift the turret.
 
The next question is.. Left handers or right handers... I vote for left handers.

Whatever hand directs the cutting forces into the bed, not trying to lift the turret.[/QUOTE]

So you don't like Mori-Seiki's either, hunh ? :stirthepot:

What a bunch of shit. I understand the theory and it sounds great, but I have never had any issue as a result of running with M3. I run Moris all day. Along with a host of other machines. And I DO NOT baby them. When a prospective Employer calls someone on my reference list they would say "yeah He's great, but holy hell he runs hard all day) no rest for the Wicked.

And no SeaMoss, Mori is not my favorite either, but that theory is just a theory and is garbage IMNSHO. One of those things like shit my Honda just seized, oh yeah I forgot to oil it for a year but it's a Honda, so WTF?

R
 
I was stirring his pot, not yours :D

You have to admit, it is kind of a peculiar system tho. Not sure why they went to all that trouble ?

It is weird :nutter:, maybe the original Engineer was thinking chip control? IDK. But using the Casting as reference point is dumb. Why not use the same logic with the Spindle bearings? If you turn a part using M4 then the force is drawing away from the Casting right? And those bearings are under considerably more load than the Hirth or the bearings in the Turret.

I just see that theory here and there and it seems like fixin' what 'aint broke, or reinventing the Wheel. :willy_nilly:

Robert
 








 
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