Hardinge HCT threading

I have an elderly HCT, the one with a bob weight. I have refurbed the threading kit but never used it, I have got the manual and understand how to set it up.
My problem is that I have to make about 300 Ali threaded tubes, they will be about 1 3/4" diameter, 3/4" long with 18 tpi thread. I am still waiting for the sample to come.
I plan to hold the blank in reverse jaws in a 3 jaw chuck, skim the outside, face and chamfer the end and thread,will the HCT handle a thread this coarse or am wasting my time making the leadscrew and follower?

I have only seen a copy of that style threader work many years ago. I think they were doing a similar pitch in stainless. If you can set your infeed at 29 degrees it will lessen your tool pressure. Unless your tubing is heavy walled, I would be more worried about chatter from the tubing flexing and it being 3 lobed when you take it off the chuck.
Just looked and I have an 18 pitch leadscrew (no follower) that came off a Tsugami chucker. It is probably interchangeable with the later HCTs. If you want it, just pay the shipping from Texas. Post will be about $25.00USD and will take about a week to 5 weeks to get there. If you are interested in this let me know and I will give you the measurements.

Those threading devices do a box cycle just like a cnc. I think you will be OK with 18TPI, been years since I had one. I believe there is a setting for max number of cycles and an increment for each cycle. There is no "compound" to set over. Tool goes straight in if my memory is correct. I had the Hardinge insert tooling I believe.
When set up right, they do a great job.
Bill

The sample has come now and it is 18 TPI x 2" od , .670" long and a bore of 1.640" so Fred, yes please, I would like to see if your leadscrew would fit, I can make the follower.
Thanks guys for the input
Peter

The lead screw is marked Hardinge and 18 Pitch. It is etched in with somekind of scribe. So it is probably not Hardinge but a copy to fit Hardinge. The bore is 1.875 plus a tenth or 2.

I have seen an AT work and its cycle was canned. I am assuming that your elderly HCT is manual. Tsugami was great at copying not very great at inventing so I am assuming your HCT was the basis for the Tsugami. I watched my forman thread with the Tsugami 38 years ago a couple of times. He cranked the infeed with his right hand and operated the pull down to engage the follower with his left. I remember the infeed as bolted on to the slide, I would have thought he could have angled the infeed, but that was a long time ago and my memory of it is a little fuzzy.

Had one. You don't say what the material is but unless it's something nasty it'll do it just fine. Ya, no compound to set. Maybe make a spud with a cap to hold your part

Peter-

I chase thread some steel production items on a manual Hardinge ESM (smaller "splitbed" lathe).

My thoughts are
1.) I would use a step chuck and closer on the part you describe.
This will keep the part round instead of lobed, keep it from cocking, and it is reliable, no thinking involved after set up other than to keep it clean - repeatable. 300 pcs, I would not think of using a 3J chuck unless someone was making me do it for punishment.
2.)I cut threads up to 10 pitch (so far) & sometimes make a run of 14 pitch square thread, though that one is in brass. But as a rule you are not going to do them in one hit, even 18 pitch. I work out a sequence and finishing number on the tool infeed, say .010 first pass, then .005 for however many, then .002, then spring pass. Once in the flow of work, it goes pretty quickly. Far faster than an engine lathe.

2a.) I have imagined that it would be possible to use a chaser from a tangential or geometric head, in a holder, and do threads in one pass. However, the feed would have to be toward the headstock (instead of away as is typical for chasing, at least on the ESM's) and there would have to be a provision on the (shop built) holder for trip release, to make it effective and worthwhile. so far I have not experimented beyond some back-of-envelope doodles. I can almost assure you that a 3J chuck would not hold securely for that, though.
Definitely the pot chuck & ring closer; or in your case an expansion collet with a shoulder.

smt

Hardinge made HCT lead/follower sets down to 8 TPI, so 18 TPI is no sweat. You will have to take as many passes as you would on any manual threading lathe considering the setup; this is not like a die head that works in a single pass! All the HC threading attachments I can recall in detail only feed directly in.

You might consider bringing up a bullhead center in the turret to give your tube more support.

Remarkably I have found a Leadscrew and follower in 18 pitch here in the UK so I am ready to go. Many thanks to you all for the advice, yes it seems that the feed is only available radially so I can not angle the tool, perhaps this is to equalise the load on the leadscrew and follower to stop them jumping out of engagement during machining.
I will look at an expanding collet setup to hold the part in place of the 3 jaw,
Thanks again
Peter

Peter-

I don't know what the tolerances are on your threads.
If you have secure work holding, the chase threading will repeat very, very well. However, on the ESM's it is possible to "influence" the final cut depending on how hard the operator leans on the follower. Perhaps as much as .002 or a little more in extreme variation. With normal routine pressure, I'm convinced the variation is the same or less than part-to-part variation on a somewhat used engine lathe, going only by the dials on both type operations. The chase threading gives the opportunity for 1 - 3 (or more) spring passes at the final end, if you feel less than confident; because it is so fast.

Here's where I'm going: like with any set up, it can be useful to mic the first few parts, and every now and then in between. This will "calibrate" your wrist and inform your eye, and you can then hit +/- .001" or better just watching and feeling what happens after a few parts. The HC's are nice in the respect that they have a bob weight so the pressure (IIUC) can be more uniform. I don't really use a standard with the thread mics, just mic the mating part, get a good fit, mic the work, and then keep that standard thread mic reading. (unless your tolerances are to a published standard)

As with any manual threading, a quick final touch up de-burr with a triangle stone or clean up with the butt end of a wooden (cedar) shake can suddenly make a big difference in fit. I've never tried topping inserts. I do grind HSS bits in a spindex to form so they can be sharpened quickly on the surface grinder with just a top grind near the cutting edge.

one last note: HC's are more closely coupled than the ESM's, which have a gear train and the "hob" sets between shoulders, giving some slight end motion; so perhaps HC's will not evince the following happenstance. On the ESM, if you let the screw drive the follower without hand influence, or if you try to lead the follower motion (assist with forward motion) it can sometimes lead to drunken threads. Let the hob or master push the follower, with ever so very slight hand tension against the thrust. If you thread at the speeds possible with these, that will happen more or less automatically, though
smt