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Recommended lathe tooling insert type

texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
I have been using HSS and brazed carbide tooling. I can't honestly say I know all my geometries, speeds, hp formulas and so on. It's something on my ever expanding "to do" list, but in the meantime I'm just using and/or doing what I think can work, and a little trial and error.

While I'd like to evolve into doing some more interesting work, mostly I've been cutting bushings, spacers, and a little shaft work. Pretty much straight ahead, or square cuts.

I recently purchased a 3/4" Komet tool with triangle-ish inserts for a particular cut I was thinking of. And I have been thinking to add or build a set of insert type tools. But I don't know squat about them. Are there preferred types ? Are Some outdated ? Which are junk ? I see a lot of Komet tooling available with that triangle shaped insert, as well as a variety of inserts with that shape, but different cutting edge. Do they all fit various tools, and tool makers ? And I see a variety of letter coding for insert types WNMG, CNMG and such.

Anyway it can be a bit mind numbing trying to decipher what is what. I was curious if anyone had any opinions or useful info. Recommended brands or types. I would also like to do some boring on lathe or milling machine and I see Komet tooling for mills with similar inserts, if they are the same insert types I can see that as desirable. Thanks for any info.

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Illinoyance

Stainless
Joined
Aug 24, 2015
You should set up around a commonly used insert types. These are likely to be the least expensive. Proprietary insert designs like the Komet you showed are going to be more expensive. An insert like TNMP is quite common. It offers positive cutting rake which is probably best on an older, slower lathe. The TNMP or TNMG inserts give you 6 cutting edges per insert. Inserts like CCMT would work well but has only two usable cutting edges. The WNMG inserts are similar in usage to to TNMG but have a much stronger cutting edge. The WNMG also has the advantage that you can turn or face with the same tool without re-positioning it. CCMT are also suited to turning & facing with the same tool.

There is an enormous range of insert geometries and chipbreaker styles. I think those I suggested would be a good place to start. With the TNM? ow WNM? geometries you get an almost endless choice of edge preparation and chipbreaker. You can change from positive to negative cutting geometry. That will be determined by the 4th character in the insert designation and the chipbreaker design which is indicated by a suffix to the insert designation. If your lathe doesn't have the balls to hog off a big chip you should probably select a chipbreaker for light finishing.

For aluminum use a polished insert like CCGX, it fits the same holder as CCMT. I have some old TNMS from Kennametal with a polished surface but don't know if they are still made.
 
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v8packard

Aluminum
Joined
Jul 9, 2013
Location
Chicago
This is quite the subject... I use a few different styles of inserts on my Southbends, in many grades and geometries, along with HSS and brazed carbide.

Most (all?) of the brazed carbide I see really needs to be ground/honed/lapped to get the best cut and life from the bits as delivered. Which means dedicated grinding and finishing wheels, stones, etc.

I do use a lot of HSS. I have a drawer full of all kinds of configurations I have ground and reground. I like it for a lot of things. Grinding them is a great way to get a feel for the geometry of the cut. You can make changes as you wish and sharpen them again and again. The price is low and blanks are easy to find, as are used bits. When you grind some do not be afraid to give your edge plenty of positive rake. All kinds of info here and elsewhere on the net and in books on grinding HSS. Do stick with it, even as your insert collection grows.

As for inserts, I use WNMG a lot. As stated, it can turn and face, has 6 edges per insert, and comes in all kinds of grades and profiles. Another I use a lot is CCMT/CCGT/CCGX. I use these on small boring bars as well as turning holders. I use a Korloy CCGT insert on aluminum and brass, but I find it works well in plastic and leaves a nice finish on 1018 and 1144 steel. The steel wipes out the insert fast. It is not meant for that, just discovered it by happenstance. I also have DNMG and VNMG holders set up for when I need to profile or work close to the tailstock center. I managed to go a long time without trying a CNMG insert. I was given a holder this past spring, and now this seems to be insert I am acquiring the most. Seems like every possible combo is made in CNMG. Downside is you need different holders to use all the cutting edges. That is not the case with WNMG. But I just got a face mill that also uses CNMG, and this will also use the edge unused by right-hand holders. As you can see, there is no one perfect insert style.

I haven't even mentioned parting and threading inserts... There is a whole alphabet soup of holders, insert shapes, grades, and geometries. Different manufacturers rarely use similar similar nomenclature for comparable inserts. If you have not already done so, pick up a copy of Engineers Black Book. It contains very informative sections on this very subject.

I hope this helps, I know it is a lot to digest. If you have a particular type of job at hand, I am sure someone here can give you a recommendation. Lastly, dont be afraid to try different speeds and feeds. Carbides like to be pushed, and when you get into some deeper cuts they work surprisingly well on the Southbends.

Marc
 
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texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
You should set up around a commonly used insert types. These are likely to be the least expensive. Proprietary insert designs like the Komet you showed are going to be more expensive. An insert like TNMP is quite common. It offers positive cutting rake which is probably best on an older, slower lathe. The TNMP or TNMG inserts give you 6 cutting edges per insert. Inserts like CCMT would work well but has only two usable cutting edges. The WNMG inserts are similar in usage to to TNMG but have a much stronger cutting edge. The WNMG also has the advantage that you can turn or face with the same tool without re-positioning it. CCMT are also suited to turning & facing with the same tool.

There is an enormous range of insert geometries and chipbreaker styles. I think those I suggested would be a good place to start. With the TNM? ow WNM? geometries you get an almost endless choice of edge preparation and chipbreaker. You can change from positive to negative cutting geometry. That will be determined by the 4th character in the insert designation and the chipbreaker design which is indicated by a suffix to the insert designation. If your lathe doesn't have the balls to hog off a big chip you should probably select a chipbreaker for light finishing.

Thats good to know, I didn't realize Komet was a prorietary type. Common items would make sense. I'm not sure how much my lathe can handle yet, as I have not really dug into any cuts. It's a south bend 16" with a 2hp motor, but I have not installed a tach, or shot it with a photo tach either. Pretty much I go slow and easy for now. I generally do .005-.010" passes on cuts. I know bad things can happen by going to slow, but I'm not taking deep cuts yet. As my skill and confidence grow I will probably have at it more. If need be I'm thinking I might add a 3hp motor.

Right now time is not an issue. I don't expect to do production type work. I think repairs, repair parts, and some custom items may suit me more. As its not my main livelihood most of what I do will be low pressure time wise. Though I see vids of guys doing really cool stuff and it makes want to do more.

This is quite the subject... I use a few different styles of inserts on my Southbends, in many grades and geometries, along with HSS and brazed carbide.

Most (all?) of the brazed carbide I see really needs to be ground/honed/lapped to get the best cut and life from the bits as delivered. Which means dedicated grinding and finishing wheels, stones, etc.

I do use a lot of HSS. I have a drawer full of all kinds of configurations I have ground and reground. I like it for a lot of things. Grinding them is a great way to get a feel for the geometry of the cut. You can make changes as you wish and sharpen them again and again. The price is low and blanks are easy to find, as are used bits. When you grind some do not be afraid to give your edge plenty of positive rake. All kinds of info here and elsewhere on the net and in books on grinding HSS. Do stick with it, even as your insert collection grows.

As for inserts, I use WNMG a lot. As stated, it can turn and face, has 6 edges per insert, and comes in all kinds of grades and profiles. Another I use a lot is CCMT/CCGT/CCGX. I use these on small boring bars as well as turning holders. I use a Korloy CCGT insert on aluminum and brass, but I find it works well in plastic and leaves a nice finish on 1018 and 1144 steel. The steel wipes out the insert fast. It is not meant for that, just discovered it by happenstance. I also have DNMG and VNMG holders set up for when I need to profile or work close to the tailstock center. I managed to go a long time without trying a CNMG insert. I was given a holder this past spring, and now this seems to be insert I am acquiring the most. Seems like every possible combo is made in CNMG. Downside is you need different holders to use all the cutting edges. That is not the case with WNMG. But I just got a face mill that also uses CNMG, and this will also use the edge unused by right-hand holders. As you can see, there is no one perfect insert style.

I haven't even mentioned parting and threading inserts... There is a whole alphabet soup of holders, insert shapes, grades, and geometries. Different manufacturers rarely use similar similar nomenclature for comparable inserts. If you have not already done so, pick up a copy of Engineers Black Book. It contains very informative sections on this very subject.

I hope this helps, I know it is a lot to digest. If you have a particular type of job at hand, I am sure someone here can give you a recommendation. Lastly, dont be afraid to try different speeds and feeds. Carbides like to be pushed, and when you get into some deeper cuts they work surprisingly well on the Southbends.

Marc

I have quite a bit of brazed carbide myself. I like the ability to shape and sharpen those and HSS. Currently I've had to sharpen them like a bit of a gorilla, but I'm near completion of an old Hammond tool grinder and I expect it to be pretty awesome. I need to update it a bit but I have a thread on it here:
http://www.practicalmachinist.com/v...y-builders-tool-grinder-model-cb-77-b-339938/

I have been collecting some other machines, a Bridgeport mill, another tool grinder, a Heald rotary surface grinder, a Brown and Sharpe No 5 surface grinder. Plus I'd like to add either a cylindrical grinder or a universal grinder. Besides needing to do some work to all of them, I've been doing a ton of reading and research and its an ocean of information. Particularly as I'm not a machinist by trade, so a lot of it is new to me. My mechanical skills are real solid and pretty diverse, so its not all Greek to me, but I do end up with a lot of FNG questions lol.

You guys definitely help a lot. It's exactly the kind of answers I was looking for to get some direction. And I am interested in boring, as well as getting parting and threading tools. I really appreciate it.

Charlie
 

tobnpr

Hot Rolled
Joined
Sep 27, 2015
Interests me as well, seems I can't get the surface finish I'd like when turning 4140- but cannot locate a chart of feeds/speeds for carbide...
2x HSS? 3x HSS?
 

kenton

Hot Rolled
Joined
Dec 15, 2015
Interests me as well, seems I can't get the surface finish I'd like when turning 4140- but cannot locate a chart of feeds/speeds for carbide...
2x HSS? 3x HSS?

I don't turn much 4140 or regular steel in general so i'm nowhere near an expert but the last time I turned some 4140 I was messing around with my depths of cut and chip load trying to fine a finish I liked. After I decided on one I liked I roughed .12 of the diameter in one pass and was shocked at the beautiful shiny surface in front of me. Of course i didn't have enough material left to do it again so I had to settle for the dull finish I had originally selected.
 

v8packard

Aluminum
Joined
Jul 9, 2013
Location
Chicago
Something I did not touch on in my previous post was depth of cut. The best finish from insert carbide is often obtained when the depth of cut is 2-3 times the radius of the insert. In order for chip breakers to work effectively you need a depth of cut at least as much as the radius on the insert. This why a lot of people feel insert carbide is not the best choice for machines like the belt driven Southbends. It takes a good bit of power and rigidity to generate the surface speeds, feeds, and depth of cut to reach the sweet spot of many inserts.

Having said all that, you can try a bit more feed rate than you might normally use. Something that you might feed at .007-.010 ipr, try at .012-.015. Maybe try a faster or slower speed, depending on where you are at now.

All of the insert manufacturers give speed and feed suggestions for their various grades and profiles. I find these are sometimes optimistic, and often find myself running the inserts outside of their suggestions. This is really an involved subject. I have been working very closely with it for almost 10 years, and it is still a chore for me.

Marc
 

v8packard

Aluminum
Joined
Jul 9, 2013
Location
Chicago
Tobnpr,

Not to threadjack, if you can tell me what you are doing with the 4140, like the size, speeds, what you are cutting it with, and maybe the machine setup you have, I could try to offer a suggestion. I often work with 4140 pre-hard and ETD150. In my 16, I usually turn approx 2 in diameter at the second highest speed with Iscar inserts, general cutting at .010-.012 ipr feed, and as much depth as I dare. Finish passes at around .004-.007 ipr. I am happy with the finish, though I would not call it a mirror finish.

Marc
 

texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
Thought I'd start with WNMG types. Trying to research some brands and differences it seems that besides left and right tooling I see that actual tool holder number or code is different from insert number, though I suppose a charcter or two of tool holder number indicates insert type. Another difference i see is they have an indicator shown as 43 or 33, 432 or 332, and 1/2" or 3/8". Which they all appear to mean 1/2" or 3/8" which is the center circle of insert for mounting fit I gather. This being pretty crucial for having matching insert/holder types.

Knowing which size shank I wanted helped cut down the list of options, which is 3/4" in my case. Trying to stick with USA made items I have been looking at Valenite, Kennametal, Dorian, and the like. With Valenite It appears they were USA made until atleast 2010 when they merged with Walter to become Walter-Valenite, not sure where they are made now but show production facilities in China and Germany. For low cost stuff I see Shars prices are ok, but for some reason I can't remember I'm thinking their quality is questionable.

Using ebay You need to get a bit creative in your search. Example, I put in " 3/4" lathe tooling" and I get results, but I think many sellers don't know what they are selling, so using various searches combining brand name, insert type, holder type, and so on produces a whole lot of better options. Some look like they were specifically used for crashing machines, lol, but that's just my opinion.

I won an ebay auction on a right and left Valenite's that holds WN-33 inserts. Price for both including shipping came in at $46. All used inserts, but with some new corners I'm told. I'll see how they look in front of me, but I think I did alright.

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v8packard

Aluminum
Joined
Jul 9, 2013
Location
Chicago
Not a bad place to start, and the price for two holders is certainly reasonable.

I use a lot of 3/4 shank in my CXA tool post. As you can see in your pictures, a right hand holder has a code of MWLNR-123B. M is the insert clamp, in this case clamp and pin lock. W is the insert shape, a trigon. L is the approach angle of the insert, in this case 95 degrees. N is the relief angle for the insert, in this case 0 degrees. R is for right hand cut direction. 12 is the shank size, 3/4 or 12/16. 3 is the insert size (inscribed circle) of 3/8. And B is the over all length, in this case 4 1/2 inches.

If you wanted a holder in the same configuration but for a 1/2 insert size, it would be MWLNR-124B. A 1 inch shank would be MWLNR-164B. And so on. This is where it pays to study charts in books and on the web.

You might find that WNMG inserts in 3/8 IC are less expensive than 1/2. Buying them new is pretty expensive if you have to buy package quantities of 10 inserts. At $15 per insert, you spend $150. Deals can be had on eBay, craigslist, etc. One thing that may help is smaller suppliers may sell inserts one at a time for almost decent prices if they have that insert in stock. I do that sometimes with KBC Tool. If they have open packages on hand they sell me one insert to try without even questioning anything. Of course, if I like it I buy a package the next time around. Might be worth seeing what the smaller places have in your area.

Regarding country of origin, most all the holders I have are either USA or eastern European made. Might be that insert manufacturers but the holders from another company and just re-package them, and only few companies actually make the holders. In fact I think I have seen someone post on this forum that actually manufactures holders.

I think you will have the most luck on searches if you search WNMG, or WNMG holder, or MWLNR, etc. Once you find inserts you like you can search for those specifically.

I hope this helps.

Marc
 

hitandmiss

Titanium
Joined
Jul 31, 2010
Location
Rochester, NY USA
The WNMG-43X and the CNMG-43X inserts in 1/2" IC are the work horse of the industry.
More choices are available in chip breakers, coatings and materials. Even ceramic and CBN are available for hard turning.

I don't try for optimum speeds on my 10L.
Most of my work is done at 400-500 RPM.
WNMG-43X insert for roughing and a brazed carbide to finish. I use a 400 grit diamond hone wet with mineral spirits to give the final finish to a brazed bit.

Bill
 

texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
I did receive my WNMG holders, and they are in very nice shape. In shopping around for inserts i bought two different grades in 10 packs that fit those holders. Those grade inserts happen to be original Valenite NOS and I got very nice deals on them I think.

As I was shopping and researching I'd thought I'd share, though it may be obvious to the experienced. Besides tool type, insert type or shape, there is a wide variety of grades for each type of insert. Generally speaking various grades based on the type of metal you're cutting. And if that were not interesting enough, each manufacture uses their own number designation to indicate which grade.

One of the pack of inserts I ultimately purchased was Valenite WNMG-32.52-LM grade VC101. What the hell is VC101 ? In searching I found various grade cross reference charts. Many of these charts give a general idea of type of material you're cutting, as well what kind of cut, be it rough, medium, finish and such.

On the #2 post in this thread, J Gills (formally of J Gills Band) posted a real nice link to carbidedepot. We'll unbeknownst to me they also have another link you can check info on grade type on most manufactures just by typeing in that grade number:
Carbide Depot Grade Look-up

More manufacture specific from American National Carbide, but nice charts and info. Its pdf, and you need to click a button to roll it clockwise:
https://anconline.com/images/stories/literature-pdfs/pdfs/TechnicalBrochure.pdf

If you google a wide variety of things you can find different kinds of charts, figured I'd post some example pics for anyone interested:

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iwananew10K

Diamond
Joined
Sep 12, 2010
Location
moscow,ohio
my effed memory says vc101 is a tough grade for stuff like interrupted cuts, won't leave a real good finish but can take one hell of a beating.
 

taildragger

Plastic
Joined
Mar 2, 2017
Texas Gunsmith -

You might be confusing J Gilles with J. Geils who passed away 4-11-17. The J. Geils Band was one of my favorites back in the day and most of my hearing loss is due to listening to "Serves You Right To Suffer" at high volumes.

All the best.

Tom
 

tobnpr

Hot Rolled
Joined
Sep 27, 2015
I had to look it up... Peter Wolf is 71....holy crap.
At least, my sons (25 and 20) appreciate real rock from the 70's!
 

taildragger

Plastic
Joined
Mar 2, 2017
A little trivia. Peter Wolf was married to Faye Dunnaway for a short time. During my time at CU in Boulder the Chicago Bluesmen were touring the college campuses. I was able to see a lot of the greats before they passed on. I had several sign my harmonica cases. Muddy Waters was one of them. In my opinion he invented electricity when he created the Chicago amplified blues recordings for Chess Records with Little Walter on harmonica. Sorry for the off topic comment.

Tom AKA Taildragger
 

texasgeartrain

Titanium
Joined
Feb 23, 2016
Location
Houston, TX
Resurrecting a thread I started almost 3 years ago. . .

A lot of good info in here, but as I freshen up on research. . . well my eyes start bleed, and my head is cracking open :D. Sweet Jesus, there is so many variables.

Honestly, in this life, I will probably never do all the math and get geometries, feeds and speeds perfect. I grab what I think will work, if I have poor results, I try something else, change speed, feed, angle or whatever I can till I get a desired result.

I don't really do anything I would consider fancy on a lathe. I'd say predominately shafts, bushings, and boring for bushings. I may experiment more, or do more interesting things later. But most I consider pretty straight ahead. Materials I cut are usually cast, bronze, or one form of steel or another.

I am looking to casually shop and acquire 1" holders and inserts. If its like WNMG I'm thinking 1/2" insert size.

Which tools, with which shape, and which direction are you guys using most often ? Common inserts ?

Also if you look at diamond shape, square, and triangle. . . feeding the point straight into work. . . Do you have a preference ? It would seem square might have an advantage, as you would have 2 extra corners over triangle, for longer insert life. . . anything else I'm missing ?

Does anyone have an opinion on Stellram holders ? Where are they made ? Considering MSDNN164D.
 








 
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