recommendations for best lathe threading setup
I'm looking around at what is available in cutting tools for threading operations on a lathe, and would like any experience-based or expert opinions on how best to outfit a 12" 5900-series Clausing lathe for internal and external threading. My needs might include a range of threads from 40-16 TPI for instrumentation applications and general purpose usage. I have seen information that says laydown type inserts are the best if you go to insert technology, but I am concerned that they may be limited for smaller ID threading work. I have very limited experience in single point threading, so I'm open to any considerations.
I have a Clausing 5914 lathe and use the size A Swiss 40 position QC tool post with retracting internal (AFI) and external (AFE) thread cutting holders. The larger size E tool post would probably fit the lathe as well. I have had great success with this equipment. I will warn you that it is quite expensive. Even when I bought my set it was half the price of the new Jet 12x36 lathe for which i bought it.
I would really like to make one of those retracting thread cutting holders for my Aloris tool post. I just need to find someone with one to get me some close up photos of the workings so I can reverse engineer .
The carbide insert threading holders do a great job for external threads and I use mine all the time. For internal threads you can buy a threading bar that uses inserts but I don't have or use them. I make my own boring bars and sharpen cutters to thread with. Internal threading can be tricky in a blind hole.
The lay-down threading holders and inserts is the most expensive to get into, but also the most flexible and produce the best-quality threads that can be single-pointed. If you use the partial or full-form inserts, you can't use the same inserts for I.D. and O.D. threads because of differing thread heights.
If starting out with them, the cheapest way into it is getting the generic inserts that cover a range of 60 degree threads, but doing that you'll sacrifice quality because the insert can't "top" the thread and you'll have too small a tip radius for coarse pitch threads, too big a tip radius for fine threads.
When a job comes up that you're going to do a lot of, it's time to buy a specific-pitch cresting insert. Add to the collection as time and money allow, you'll never regret it. Beautiful-looking threads. For O.D. threading get a holder that takes 16EL/R (1/2" I.C.) size inserts, as those afford the widest range of thread pitches in cresting inserts (8 to 72 tpi). The I.D. threading bars are more troublesome. You might need a range of threading insert sizes, depending upon how small a bore you need to get into. The insert start with 8IL/R (3/16" I.C.), and go up from there including 11IL/R (1/4" I.C.), 16 and so on. I find using threading inserts in a blind hole no worse than other styles, BTW.
Specman, I go with Pixman all the way. Out here I can buy the specific pitch, cresting, threading inserts (called full form) in two's instead of boxes of ten. They are relatively expensive - twice the price of the general turning inserts. Buying two's has allowed me to build up a fair range of threading sizes. Of course you need the holders which are expensive, but having them is a pleasure compared to grinding tools, and I find that the inserts can last a long time, with good coolant and easy cutting parameters.
J-Head, my TOS lathe has an integral retracting mechanism in the toolpost, but it is the square type post not Aloris. It's not involved, just a cam on a wedge shaped slide and works both ways, "in and out", for external and internal boring/threading. The TOS can go direct from forward to reverse spindle rotation, and has no threading dial. I use the retract and reverse method of threading exclusively on manual threading. Can easily strip and send photo's if you want, my cross and compound slides could do with a clean up anyway.
I agree with Bach and Pixman with the laydowns. Even though some on this site say you can't use them on a manual machine I've found just the opposite! They work great. I use Carmex ( made in Israel) and they perform just fine. If you want American made Valenite has them, 'cept Carmex makes them for Valenite and cost less. Pictured below is a head ring for a hyd. cyl. The thread is 9" - 12, so I D doesn't matter.
We also have good sources for buying threading inserts in small quantities here in the USA. MSC comes to mind, but a lot of local distributors can also supply them. Inserts from Carmex, Valenite, Kennametal and others work well. I think the Carmex threading inserts are a good value in their uncoated grades. You're typically threading at low speeds anyhow because of machine limitations (or operator hand-eye coordination), so for many applications coatings are little advantage for more money. Do use coated inserts on abrasive materials though.
Personally I don't care for the way Sandvik Coromant labels theirs as "R166", and that they price them too high makes it easy to say no.
Ifanger stuff is the cat's miaow for internal threads especially in small sizes.
I believe there are US manafacturers offering similar equipment (Armstrong, maybe?)
Nice work Ray! That's a pretty part, and proof positive that cresting inserts can be used easily on manual machines. I use them and have similar experience, though no pictures to show.
Originally Posted by Ray Behner
You're right about Carmex making some threading inserts for Valenite, though not all by a long shot. Some are still made at their plant in Westminster SC, as are the vast majority of their turning and milling inserts.
Ifanger tools are Swiss-made and Alouette Tool is the only US importer/distributor. It is good stuff, but pricey and somewhat limited stock. Alouette only keeps the big movers on the shelf here in the US.
Originally Posted by Troup
For very small I.D. threading, I like the Vardex "Micro" system of solid carbide bars because they can be had double-ended, are of good carbide, and well-stocked in WI. I think thy're having a special deal for their single-ended ones right now where you get a free holder for buying 5 inserts (bars).
Originally Posted by PixMan
Thanks for the compliment! That thing was a bear. Had to make it out of
10 1/2" solid at 77#. Now it weighs 21#. Talk about CHIPS!
Ok, assuming "laydown' means the actual way the insert fits into the holder, Flat , cuts in the same fashion as a standard square, diamond insert?
Thanks to all who commented. I'm not sure I want to spend $800-1000 on the Swiss Multiquick stuff (the Penn Tool site operates on the tried and true "if you have to ask, you can't afford it" principle, apparently). I'll probably go with the inserts that cover some range of pitches.
You could probably find a decent used holder on Ebay. What size shanks can your machine take? For the 16ER size inserts, holders can be had for shanks sizes 3/8" to 1-1/4".
From Valenite they're specified as "SER xxxx X16" format. The "xxxx" represents the shank height i.e. 0500 = 1/2", 0750 = 3/4", etc. In the "X16" format, the letter represented at "X" is length of shank, i.e. D = 2.5", H = 4", K = 5", etc. The "16" is the insert size.
Kennametal and Vardex use the LSASR-xx3 format. The "xx" represents shank size expressed in eigths of an inch. An LSASR-83 is 1/2", LSASR-103 is 3/4", etc. Metric shanks are also available.
The first inserts to buy would be 16ER-A60 for threads from 48 to 16 TPI, and 16ER-G60 for threads from 14 to 8 TPI. Later, buy a couple of pitch-specifc inserts for those threads you do most often.
These folks make nice tools (Thinbit):
I have a tiny internal threading tool and it works great.
I bought a Carmex kit from MSC years ago. It had a selection of inserts that came with the kit. I then buy inserts as needed.
Both external and internal kits were purchased. I think the other one is Valenite, but it is also made in Israel, so I'm guessing it is Carmex also.
For really small bores, I go with one-piece carbide thread tools, like Accu-pro and SCT(?). The ones that look like boring bars, but are thread tools.
I do prototype and repair work in the lab here. So the kits were nice to have. I then buy as I need, or grind a tool from HSS for the boring bar, or sometimes grind a one-piece tool from a piece of HSS. I have experience grinding my own tools, but I like the insert stuff for threading especially.
I also like to have thread inserts for my top-notch type tooling. This is the tooling I use for larger grooves and some turning/facing work (fine work). I can get threading inserts for it for external threading (they make internal tooling too, but I don't have a holder.) I think my top-notch stuff is either Valenite or Kennemetal (the holders, I'm not sure of the inserts). Nice and rigid.
You guessed right, many (though not all) of the Valenite ER threading inserts are made by Carmex in Israel. You did well buying sets like that. For internal threading in small bores, I also go with the solid carbide Accu-Pro, SCT, or (preferred) Micro 100 brands. Anything big enough to get an insert in, I go with those.
I haven't yet decided what to buy exactly, but the range of informational responses is great. To answer Pixman: The toolpost I have is a BXA-size clone (typical Chinese, although it's not too bad quality-wise), and the holders will take a 5/8" shank typically. I've been scouting eBay for what may be available.
On a related topic -- What about those Aloris-style threading tools with the short blade that sort of hangs off the side of the holder? Do those work well? Obviously not suited for internal work, but are there disadvantages to that sort of setup, other than the fact that the cutting tool is HSS (I think)?