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Installing and aligning small boring bars in cnc lathe

Houndogforever

Hot Rolled
Joined
Oct 20, 2015
Location
Boring
I have an old Hardinge Conquest 42 lathe, 1988 with a Fanuc OTb control.

I make some small parts and need to set up a 1/4" boring bar.

How do I go about aligning the center of the insert to center of bore?

I swear, I just put them in and face off a blank to remove the tit. If that is good enough, ok, but it seems halfass to me.
 

Booze Daily

Titanium
Joined
Sep 18, 2015
Location
Ohio
Most holders have a flat on them for the set screws on the tool block. I’ve seen guys put them on the surface plate and use a height stand to get them on center.

I’m even more hack than you. I just eyeball it to the station 180 from the b-bar. Only bit me once when a long angle had to be +/- 1/2 degree and the off center of the bar made the angle out of tol. Parts were reworkable but it was still embarrassing.
 

wmpy

Hot Rolled
Joined
Dec 16, 2011
Hardinge has a tool that came with their lathes to align boring bars to center. It mounts into the 1.5" wide space where the stick tools go and has an arm that extends down to the tip of the tool to show you where center is. I think we have a couple, but I never use them. They're cumbersome, and my results have been fine using a straightedge against the tool and lining it up by eye with the turret.
 

implmex

Titanium
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Hi Houndogforever:
I run a Prodigy 5C gang chucker so I have all my tools mounted to a platen instead of a turret.
That makes my life very simple...I can and do, just drop gauge the tool tip.
In my work I need to be very accurate with my tool height...within 0.0005, but they're all custom tools, mostly tiny boring bars.
My drop gauge base is a big ejector pin cutoff with a powerful rare earth magnet bolted into a recess in the underside so I can stick it directly to the table.
I surface ground the rim of the pocket so the post of the drop gauge is perfectly perpendicular to the base.

Ideally you can find a way to do something similar on your turret machine...some custom doohickey you can stick to the turret that's repeatable but removable, and can be moved between stations.

I don't know how accurate you need to be...if you regularly run boring bars under 1/16" as I do it needs to be pretty damned good, but if most of your work is bigger, you have a lot more latitude.

Another way I have tried is to make a split pin that I can chuck, indicate to level, and then compare to by running the tool up close to it and sliding a ground block from the flat of the pin onto the tool tip.
It's a PITA but I can get a tool tip within 0.0015" or so reasonably reliably that way, by rotating the tool tip up or down until the ground block doesn't catch anymore when I slide from the pin to the tool tip.
Did I mention it's a pain in the ass?

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I am also using gang tool machines. I set an old insert on the flat and eyeball it level before locking it down. Do not know if you have a tool holder in the turret that can be pulled and this done on the bench or not. Perhaps one turret position would allow you to level it. This works for me with boring bars down to .040".
 

Fancuku

Cast Iron
Joined
Dec 7, 2018
I don't think Conquest 42 is a gang tool lathe. I think it has a standard turret.
Houndogforever, what you are doing is fine. No need to get crazy with it.
 

implmex

Titanium
Joined
Jun 23, 2002
Location
Vancouver BC Canada
Hi fancuku:
You are correct, the Conquest is a turret machine.
So the point of my post was that his problem is going to be more complicated than mine was.
But with some creativity he may well be able to find a way that is similar in principle to mine.

With regard to how anal you have to get about center height...well it depends on what you have to make.
Anything 1/4" diameter and above is orders of magnitude more forgiving than anything 1/16" and below.
So the OP has to decide how important it's going to be for his application.
Getting it right never hurts, but if it's painful to get there maybe not so much.

I make all small stuff, so I have to care a lot... I've tried a few different ways on both turret machines and gang chuckers.
Drop gauging them when you have to care a lot has been the easiest and most consistent way I've found.

Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
Vancouver Wire EDM -- Wire EDM Machining
 

FredC

Titanium
Joined
Oct 29, 2010
Location
Dewees Texas
I don't think Conquest 42 is a gang tool lathe. I think it has a standard turret.
Houndogforever, what you are doing is fine. No need to get crazy with it.

Yeah, that is why I asked if he had a boring bar holder that could be removed and the eyeball with an insert procedure could be done on a bench then the holder reinstalled. Never ran a turret machine mounted on an angled slide. Thought there was a chance there was a position where the tool holders were level to the floor.

"Perhaps one turret position would allow you to level it?" Fixed it to make it look more like a question from someone who has never ran a turret CNC.

The GT came with a tool from Hardinge for setting tool height in the adjustable holders but as you torque the screws down the height of the holder grows. Made some gauges so that like Marcus I can indicate the top of turning tools to center them. Even with these shop made gauges available, I eyeball small boring bars with an insert on the flat. Each of us has things that work for us but not others.
 

Houndogforever

Hot Rolled
Joined
Oct 20, 2015
Location
Boring
Yeah, it is a turret machine. The smallest boring bar I use is 3/16 indexable I think. At least my determining that it is a bitch is not unusual, so that makes me feel a little more positive.
Thanks for the input, you have given great ideas.
 

Omega

Aluminum
Joined
Nov 3, 2014
Most of the time I just eyeball it to center, If you want to get it really close for a small bar,Dyechem the material
end and face with your turning tool to .01 of center then line the boring bar to the tit that's left
 








 
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