Okuma lnc8 tooling insert up or insert down?

[dreammstr6]

I’m confused on whether the insert should be facing up or down in the turret. Looking at the programs in the machine it was run insert down. But I have been reading posts where people are arguing saying it can cause more wear on machine. Some say it has to be that way due to center line etc. anyone have a Okuma lnc8 or similar that can give some guidance. Thanks

 

[70olds]

You can run either. There are a few things I see thrown around frequently and they have their merits, but there's also a very limited range in which I think either way is "better"
.
Insert down has the advantage of gravity helping with chip evacuation. When the chips are coming off the material even if they curl towards the bar, they can't get wrapped over it.
Insert down programs run clockwise spindle rotation (M3).

Insert up means the cutting pressure is put into the bed of the lathe instead of "lifting" the turret. Essentially pretend you are grabbing the stick tool and pulling from the insert side. Insert up you are pulling into the casting, while insert down you are trying to pull the saddle off the casting. bear in mind that saddle weighs probably 1000 pounds or more, and either direction you are going the turret has to resist the rotation before anything else, so in my opinion until you are overcoming turret rotation forces I don't know how much difference it makes.

We run insert down almost exclusively for chip evacuation. I have a few older machines that due to tooling restraints or process restraints we are running insert up. If I were taking big cuts consistently I would run insert up though.

 

[dreammstr6]

You can run either. There are a few things I see thrown around frequently and they have their merits, but there's also a very limited range in which I think either way is "better"
.
Insert down has the advantage of gravity helping with chip evacuation. When the chips are coming off the material even if they curl towards the bar, they can't get wrapped over it.
Insert down programs run clockwise spindle rotation (M3).

Insert up means the cutting pressure is put into the bed of the lathe instead of "lifting" the turret. Essentially pretend you are grabbing the stick tool and pulling from the insert side. Insert up you are pulling into the casting, while insert down you are trying to pull the saddle off the casting. bear in mind that saddle weighs probably 1000 pounds or more, and either direction you are going the turret has to resist the rotation before anything else, so in my opinion until you are overcoming turret rotation forces I don't know how much difference it makes.

We run insert down almost exclusively for chip evacuation. I have a few older machines that due to tooling restraints or process restraints we are running insert up. If I were taking big cuts consistently I would run insert up though.

Thanks

 

[Mtndew]

But I have been reading posts where people are arguing saying it can cause more wear on machine.

It doesn't.

 

[sinha]

Sometimes, there can be a compulsion to use insert facing up or down.
For example, if an LH tool is needed, and it is not available, the RH tool can be inverted.

 

[DouglasJRizzo]

On my LB15, I always used LH tooling for everything except drills and reamers. I prefer to cut "down" into the machine's castings where it's stronger. On dad's LC30s, we used RH tooling and cut conventionally, as the turrets were much larger.

 

[guythatbrews]

LB15s and LB20s and all Okumas always ran insert facing down to help with chip flow. Took honking big cuts never a problem.

 

[CarbideBob]

Insert down and you help with chip evacuation.
In general I consider it a bad idea to load the machine ways in this direction.
Maybe a band-aid due to poor tooling choices?

 

[guythatbrews]

Insert down and you help with chip evacuation.
In general I consider it a bad idea to load the machine ways in this direction.
Maybe a band-aid due to poor tooling choices?

It may be a bad idea but it sure works great. We did this intentionally. If the insert faced up that was our bandaid. These were all box way machines. Ran hard and still in very good shape when we traded up. Some of the stuff we ran in the lb25s was around 18" diameter gear blanks bolted to a faceplate.

 

[William Lynn]

Our first CNC lathe was a well used factory demo from Cincinnati Milacron. It used big heavy bolt on OD tool blocks and were designed to use left hand tools with the insert up. For threading we used a drop head threading tool upside down. Last lathe used VDI 40 tool holders, which could be had in many configurations. I went with the one that allowed me to use the left hand tools for most of the turning. Got the other orientation for threading and some other right hand tools.