Why would I use a Neutral Indexable Tool Holder? Over a Right or Left handed?

assface421 · Aug 25, 2016

Hello everyone,

I was in the small machining department here in the shop, where they run conventional machines. I noticed one of the guys (Who doesn't speak English. So I couldn't ask him why.) using A neutral Indexable tool holder. I am curious why you would use one over a right or left hand holder. What are the benefits of each? Thank you for taking the time to share any input that you might have.

-Assface421

doug925 · Aug 25, 2016

I assume you mean part off inserts??..??
I use neutral mostly for ease of programming when chamfering grooves / and or the back end of a part.
The above assumes my parting blade is short coupled, and rigid enough to do so.

Outside of that, no reason I can think of.

Doug.

Perry Harrington · Aug 25, 2016

Only neutral holders I know of are used for chamfers or profiling. A right hand tool sometimes doesn't have the clearance to profile a part, but a neutral holder with the same insert will. I've seen neutral holders that present the wide insert face to the part for doing big plunge roughing on the lathe.

assface421 · Aug 25, 2016

To clarify he was turning using a Neutral tool holder.

alphonso · Aug 25, 2016

assface421 said:
To clarify he was turning using a Neutral tool holder.

That really doesn't clarify much. What insert is in the holder? I use a neutral dnmg or vnmg holder to rough out V-grooves on pulleys and rolling dies for pipe straightening machines.

PixMan · Aug 25, 2016

I use a neutral holder on a regular basis, an MSDNN 164D. It holds an SNMG43x insert and I use it for chamfering only. A neutral holder can be great for roughing when you want the maximum depth of cut with the least amount of force, just don't think you can get within a country mile of a shoulder!

Orange Vise · Aug 25, 2016

A neutral holder allows bi-direction plunging (zig zag grooving) with a steeper clearance angle. You'd typically use one of these holders with a V or D shaped insert.

Heavey Metal · Aug 25, 2016

Will turn and face.

Saves a position

JH-Q · Aug 25, 2016

One place i used to work used neutral toolholders for roughing out trapezoidal threads. They then used a full-profile threading insert after roughing.

I've personally used them in my shop for making a groove in tensile strenght test pieces. Easy to get inserts with a specified radius and angles for making a breaking groove in the middle of a test bar.

Also on some occasions, they're handy when doing face groove profiling, such as flywheels.

All of these with DNMG/VNMG inserts or the positive geometric equivalent of those. I prefer the positive geometries for most of my work, as the setups aren't always that rigid, and the number of pieces i manufacture of each part are low.

Ox · Aug 25, 2016

assface421 said:
To clarify he was turning using a Neutral tool holder.

We are all still guessing at your tool.

Is it a boring bar?
If so - there are very few apps for a 0* clearance angle. BUT maybe you have a through hole and you want a 30* back taper in your hole - you would need to have a TNMG setting dead true at 0* to make that work - w/o going to a 55* profiling tool.

Is it an OD tool?

A) Is it like a TNMG that is just setting strait out from the turret - producing a 15* angle on both sides?
That app has been discussed already.

B) Is it a RH or LH tool with 0* shoulder clearance?
Again - you could want to be able to run a back taper - or even just a back chamfer and don't have a shoulder on your part.

0* clearance tips don't like shoulders!

Is it a cut-off?
0* sucks for cutting off, but if you want to use it for grooving also - then you can make that work if you are short on available positions.

-----------------------

Sweatin' to the Oldies!
Ox

Jashley73 · Aug 25, 2016

I have a customer that uses these a lot. It allows them to do bi-directional turning, or in other words, feed toward the Chuck, plunge/ramp down, and the turn back toward the taistock. It also lets you take advantage of chip thinning, since the 45* lead-angle gives you a thinner chip, and you can feed 40% faster without over-loading the chip-breaker.

The downside, is that they create more radial-pressure against the part (in X axis) when you're turning/feeding in Z, and therefore make deflection worse if the part isn't held well. And the extra radial pressure can lead to more chatter if the setup isn't rigid.

You can sometimes use this to your advantage though. If you use one of these 45* lead-angle tools for heavy facing, the extra pressure is now pushing in the axial (Z) direction, and would help force the part back into the chuck.

assface421 · Aug 26, 2016

Ox said:
We are all still guessing at your tool.

Is it a boring bar?
If so - there are very few apps for a 0* clearance angle. BUT maybe you have a through hole and you want a 30* back taper in your hole - you would need to have a TNMG setting dead true at 0* to make that work - w/o going to a 55* profiling tool.

Is it an OD tool?

A) Is it like a TNMG that is just setting strait out from the turret - producing a 15* angle on both sides?
That app has been discussed already.

B) Is it a RH or LH tool with 0* shoulder clearance?
Again - you could want to be able to run a back taper - or even just a back chamfer and don't have a shoulder on your part.

0* clearance tips don't like shoulders!

Is it a cut-off?
0* sucks for cutting off, but if you want to use it for grooving also - then you can make that work if you are short on available positions.

-----------------------

Sweatin' to the Oldies!
Ox

Sorry to leave you all guessing what the tool was. It looked to me like a CNMG or SNMG insert on a 1/2" straight shank tool holder. He was just straight turning an impeller assembly down to size. Lots of varying depth of cut it seemed. This was a repair job not a new part.

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Why would I use a Neutral Indexable Tool Holder? Over a Right or Left handed?

assface421

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doug925

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Perry Harrington

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assface421

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alphonso

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PixMan

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Orange Vise

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Heavey Metal

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JH-Q

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Ox

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Jashley73

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assface421

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