How to machine a simple ferrule used in a compression fitting

This is the common symmetric ferrule:

http://www.horrorseek.com/home/halloween/wolfstone/Plumbing/concom_OnTube.png

I have a 9" South Bend lathe with 3-jaw chuck.

I'm thinking,

*) turn OD and drill ID on some chucked bar stock.
*) turn cone on end
*) turn as much cone as possible on inboard end without parting it off
*) have to make a parting tool with the cone angle to complete the inboard cone and part off.

The problem with this is that the parting took completes the inboard conical surface which is not what you when parting.

Don't know how good this would work machine all outside features and drill hole as last operation. The cones would be turned to smaller than the drill ID. Of course the last bit of drilling would perform the parting and again would be problematic with a gouge and rip off of the ferrule. BUT, the chuck jaws would be long enough to clamp the bar and the ferrule OD at the same time and perhaps this ferrule clamping would be enough to keep it in place as the drill intersected the inboard OD cone, cutting it off.
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I don't think it would be possible to chuck the ferrule itself on its OD and machine the cone feature. If I had a collet I would think it possible, maybe even with a 6-jaw chuck.
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Support ferrule on some kind of mandrel, possibly tapered.
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Obviously screw machines pound ferrules out in seconds so I wonder how they are set up?
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ANOTHER QUESTION: How to increase the ID bore diameter of an existing stainless steel ferrule?

Chuck on OD?

Make a "Compression Chuck" that would hold the ferrule as it is in its compression fitting. Perhaps install in compression fitting, align with tubing, remove tubing, tighten, and then drill out the entire compression fitting.

In fact, this might be a way to make the ferrule too: machine outside features and then drill a much smaller ID - small enough that the ferrule is still on the bar. Then part off.

Align in compression fitting and begin progressively drilling out ID.
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I'm done. I'm really curious what the operations are on a screw machine that manufactures them.

THanks in advance,
Tom

Machining this should be pretty straightforward: bore, machine the two conical surfaces and part just behind the rear one using a sharp, narrow parting tool. If you getting a bit of a deformation when parting (should not happen with sharp tool in brass) you can stretch it in a couple of seconds with a taper punch pressed by hand. For boring existing ferrule, mount a compression fitting in a collet or 4 jaw independent chuck, centre and lock the ferule in the fitting.

Sometimes I've had to repair damaged ferrules. I held them on an expanding mandrel for polishing.

Regards Tyrone.

Feed to stop

Drill

Bore

Reem

Insert mandrell

Skive

Remove from mandrell

To repair:

Insert mandrell

Yes, I was concluding boring from a compression fitting.

Note: if I bore and machine the rear cone, that will part the ferrule since the bore and cone surface intersect forming a sharp edge.

Oh, and the material is stainless steel


Idea for chucking ferrule itself:

To make the double taper ferrule or olive as we call them here, drill undersize, perform all ops on the outside, leaving a little meat at the rear,bore to size and swing tool to make undercut at rear part off then part off.
The undersize olive can be enlarged with a steel ball pressed through

I am sure some combination of the methods mentioned above will do the job. You may need to make some kind of mandrel or custom, expanding collet to hold it.

As to how they are made commercially, I would suspect they start by cutting a short piece of tubing and then using some custom rollers to finish it in one quick step. I can see a two piece roller in the center with shoulders for the finished edges and a single, double angled roller to finish it off. The tubular blank would be shorter than the finished ferrule so you may need some centering mechanism when it is loaded on the inner rollers. Or the tapered outer roller may do that job.