I recently upgraded my Logan 922 lathe with a quick change tool post setup and went with some 1/2" indexable turning holders
I am looking to stock up on some inserts
the ones that came with my holders have the following specs
C6 Carbide with chip breaker
TCMT 32.52
I have to be 100% honest in that I have no idea what brand or what type of inserts I should be buying or using for each material before this I was hand cutting HSS bits on a grinding stone to suit my needs
I mainly cut chromoly steel, 304 stainless steel, and aluminum on the lathe
what inserts should I use for the following ?
1. 304 Stainless Steel
2. 4130 Chromoly
3. Aluminum
4. General Cold Roll Mild Steel
I run a small motorcycle shop that specializes in vintage Harley Davidson Choppers
so everything I do is mainly small stuff where I need to face off a piece or turn down a piece and every now and then some boring and some threading work
I mainly turn lower lower fork legs to make them smooth
make up some mounting bungs
make up some wheel axles
small stuff like that
I am not a big industrial type of shop
I do spend a few hours a week on the lathe and its basically a learn as I go type deal as I never took any formal machinists school or classes (although I wish I would have)
so any recommendations on what type of inserts I should be buying would be greatly appreciated and what type I should be using for each material and any specific brands of inserts etc would be greatly appreciated
Also I dont have an unlimited budget I would like to find something that is reasonably priced as I am not doing any type of precision work etc.
This forum has been a huge help in me learning the things I have so far to operate my lathe and make up the pieces that I need
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Subject: Machinist
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- From: Lawrence London <lfljvenaura@gmail.com>
- To: machinist@lists.ibiblio.org
- Subject: [machinist] Indexable Lathe Tooling Info
- Date: Tue, 29 Jan 2013 22:05:30 -0500
http://www.practicalmachinist.com/vb/general/indexable-lathe-turning-inserts-just-few-quick-questions-259561/
Indexable lathe turning inserts - just a few quick questions
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01-29-2013, 08:18 AM #2
Cast Iron
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01-29-2013, 08:26 AM #3
Titanium
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A logan is a bit light for getting much perfomance out of a carbide insert. A hss tool would work better and wouldnt tax your lathe. Plus they are way cheaper. I run HSS on all of my lathes and it works fine for mild steel I have carbide tooling but find it is not worth it on most jobs. I am running a Lodge and Shiply model x with gobs of HP and rigidity. I hate chipping an insert on some bonehead job for a friend and thinking there goes 10 bucks. I can just regrind the tip of my hss and be back in business. I used to run cnmg inserts on everything but have since just gone back to hss and life is good.
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01-29-2013, 08:38 AM #4
Plastic
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Carbide tip tools on a manual lathe are never working like they are engineered to work, as a result the grade you use is not that important. Most tool suppliers will have a general purpose grade, usually one used for softer steels, they will be fine.
The only tip I can offer is use a strong feed rate and a faster speed than that of HSS and try not to let the tips idle in one spot as some materials can work harden, that is when you will loose the tip edge. On aluminium components smear a tiny amout of oil along the cut surface (I use my finger) this will prevent build-up on the tool, but only a tiny amount of oil as the fumes can effect non-machined surfaces by disscolouration. -
01-29-2013, 09:05 AM #5
Plastic
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thanks guys
for cutting stainless and hardened materials I should be looking at a carbide tip though right ? -
01-29-2013, 09:20 AM #6
Aluminum
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For a light Logan I would run the "M" style chipbreaker for al and steel, for the stainless and hardened bump that chipbreaker up to an M5 or so. On the hardened you should go for a harder grade (C2) and the rest run a tougher one (C5-C6).
Regards -
01-29-2013, 09:26 AM #7
Plastic
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Yes that is right, remember the tip radius is important, a cut should be of greater depth than the tip radius or you can get 'push off', but a small radius and tip the wear can be high. a starndard over here would be 0.4mm for finishing and 0.8mm for roughing or general purpose stuff.
Stainless is a soft material but the second you allow a tool to idle the tip will go, especially on HSS tools. So in answer to your last question yes, the tip tools are better, but harder to get a nice accurate finish. -
01-29-2013, 12:57 PM #8
Diamond
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IMHO you must be doing something wrong to be getting a bad finish on stainless with a suitable TCMT tipped tool (getting a finish on soft gummy mild steel is were i struggle, just run out of RPM to get to a good cutting speed). Good tips oftern have basic steel and stainless cutting data on the back. Read it and apply it. Speed, can be the hardest thing to get, but generaly the more the merrier on smaller diameter work on a manual lathe.
Alu specific tips absolutely rock in plastics and of course aluminium. Due to how they cut there a not speed sensitive. A alu specific insert will leave a lovely finish on even a 1/4" rod going around at 10 rpm. Its just slow!
The Super Alloy style inserts have alu like geometry but coatings and better angles. There designed to cut at the kinda speeds you can hit with smaller diamiter work on a manual lathe. The finish will be brilliant, tips last damn near forever. But you must not tap them with anything hard or bump them into anything when there not cutting or they chip. I use them a lot of free cutting steels were i just can't get the RPM to make other inserts or even Hss tools realy work well without running coolant - oil. -
01-29-2013, 01:28 PM #9
Cast Iron
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"A logan is a bit light for getting much perfomance out of a carbide insert. A hss tool would work better and wouldnt tax your lathe. Plus they are way cheaper."
i hear this opinion again and again, but i even run carbide on a 500 pound 3 in 1 machine and it takes off 2 mm with no sweat. also, how much is the time one spends grinding a hss bit? your supposed to hone them as well, right? -
01-29-2013, 02:42 PM #10
Plastic
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Okay so I was looking at these for maybe a threading bit
Insert, TNMC-32-NV High Speed Steel Threading - LittleMachineShop.com
and these for an HSS bit
Insert, TCMW-321 High Speed Steel - LittleMachineShop.com
and these for a carbide bit
Insert, TCMT-21.52 Carbide - LittleMachineShop.com
this is the place where I found these
if anyone has a better place to buy from please post it up
or a better bit they can recommend from somewhere I will gladly buy it from there
I know MSC is a good source but man I have no clue what I would be looking for in their catalog online for indexable cutters they have over 30,000 to choose from -
01-29-2013, 07:51 PM #11
Diamond
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TCMT is a good start. You want positive rake. Choose the largest nose radius as the insert is tougher. Forget about all the grades, just get the cheaper versions. IMHO you won't be able to tell the difference on a small manual lathe. The people telling you to stick with HSS are trying to save you $. I have broken many an insert on its first edge on a lightweight lathe, to the point where I wanted to stop flushing money. HSS will last and last since you just touch it up with a grinding wheel and a stone. It will survive any interrupted cut and can be ground to form whatever feature you want to make...
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01-29-2013, 09:02 PM #12
Hot Rolled
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Hi
I get good results with Tungaloy Cermet CCMT inserts with a Denford Viceroy (like Southbend, Boxford). I can use them like HSS (fine feed, shallow DoC). I run the lathe at full speed and get a great finish.
With all of my inserts I find they need high speeds and high feeds to get the best out of them. They don't like interupted cuts.
Dazz
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Thread: educate me - carbide inserts
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01-08-2006, 01:54 AM #1
Hot Rolled
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The latest Enco flyer has a killer deal on a 5 pc. indexable toolholder set on page 4. U.S.A. mades are about half price. I have never used this type of toolholder and am not sure about all the nomenclature. I can assume the first letter designates the insert as triangular or square but the other numbers are Greek to me. Is there a code or I thick-headed?
How is performance going to vary as compared to HSS and brassed carbide? Anything I should watch out for?
Thanks, SCOTT -
01-08-2006, 02:19 AM #2
Hot Rolled
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01-08-2006, 03:02 AM #3
Hot Rolled
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Ice--That's a nice compact insert chart.One of the better ones that I have seen.If I'm seeing it right, they have that one for turning inserts but not a seperate one for milling inserts.That's too bad it'd be nice if they had both.
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01-08-2006, 04:28 AM #4
Aluminum
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smootz,
I have two of those sets, one "import" the other "made in usa". The made in usa set is nicely machined, hardened, and black (pretty) BUT they require tcmt 32- inserts and that's a killer drawback.
That particular insert size is not popular, so your selection is limited. If you happen to be machining something that your basic tcmt insert cuts well, great. If you need a different chipbreaker or grade other than c2/c6/TiN you are pretty much out of luck. There are a few choices but they're expensive. The inserts are also rather fragile, no doubt part of the reason why the more common iso insert is thicker.
In hindsight, I wish I'd have spent the money on a couple of individual tool holders for tpg type inserts. Dorian make a nice set of those for around $200. Cost a bit more than the ones in the enco flyer, but the value is better in the long run. Just being able to get cheap inserts is worth half the cost difference.
Glenn M -
01-08-2006, 04:42 AM #5
Titanium
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That is a nice chart, so I printed it off for quick reference. The Enco catalog (print & online) has a very similar chart that has some additional information, so they compliment each other very well. The Enco chart is on page 59 of the 2006 catalog.
I bought a set of holders from Grizzly and I wish I had saved the money. Since then, I have made some and bought some off of Ebay to get most angles. I have both TP and TN style.
The triangle style of insert is not the most efficient for all purposes, at least that is the opinion of the people in the CNC forum. I am thinking of getting some other holders, but may not have enough lathe to take advantage of them. -
01-08-2006, 11:19 AM #6
Hot Rolled
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I think you will find that TCMT-3252, TCMT-3251 and TCGT-3252, TCGT-3251 are very popular inserts and are readily available from Sandvik, Kennametal, J&L, etc.
I see 6 different chip control TCMT/TCGT inserts, with 3-5 different nose radii and stocked in 6 different grades in my Kennametal book.
The TCGT inserts (G means the periphery, and therefore the cutting egde, is ground) have a sharper edge than the TCMT (M means molded) inserts. This is likley a benefit to the majority of HSMs doing lighter cuts, finising & one-piece runs.
As a side note, the TCGT (ground periphery) inserts will index from edge to edge in the toolholder pocket with greater repeatability than will the TCMT (molded periphery) inserts. However, TCMT inserts are less expensive than the TCGT inserts.
Mike -
01-08-2006, 01:25 PM #7
Aluminum
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Yes, exactly, that's my point. The tcmt321, 322, 7 323 are rare by comparison.I think you will find that TCMT-3252, TCMT-3251 and TCGT-3252, TCGT-3251 are very popular inserts and are readily available from Sandvik, Kennametal, J&L, etc.
-Glenn -
01-08-2006, 02:26 PM #8
Hot Rolled
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GlennM,
My apologies! I thought the "tcmt32-" in your post indicated that you had omitted the 52 and 51 from the insert numbers!
Mike -
01-09-2006, 04:15 AM #9
Diamond
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Glenn, I'd agree the TCMT 321, 322, etc would be comparatively rare. I'm wondering if the toolholders would be able to use a TCMT 32.51, 32.52, etc. Both are 3/8 IC triangles, screw down, neutral rake, 7* relief. The difference would be 1/8 thickness for the 321 vs 2.5mm thickness for a 32.51, for a difference of about .028" on the thickness. Unless there's a difference in the hole size, seems like they may fit in place of the 321's.
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01-09-2006, 04:57 PM #10
Diamond
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I've been running nothing but inserts for years and nothing is more true. The least expensive inserts are (surprise!) on eBay. The more common the shape, the more listed, the lower the cost.Just being able to get cheap inserts is worth half the cost difference.
CNMG-432's are used for most of my lathe work. Pafana (made by Bison) has toolholders and boring bars for this insert:
http://www.penntoolco.com/catalog/pr...ategoryID=4859
http://www.penntoolco.com/catalog/pr...ategoryID=4857
Some of the toolholders are available only in 3/4" shank, but they are easily milled to the 1/2" size needed for smaller lathes using a solid carbide end mill!!!
There are always a bunch of these on eBay, 42 showing today. Many times they sell for $.50 to $1.00 per insert. -
01-09-2006, 11:41 PM #11
Aluminum
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You'd think, wouldn't you? I tried it, the thicker inserts won't seat properly. The tool has a slight undercut on the shoulder that supports the back side of the insert, this causes the thinner insert to jam into place when the screw is tightened but the thicker 32.5x insert tips back or refuses to seat fully. That might be solved with a minor modification to the holder.I'm wondering if the toolholders would be able to use a TCMT 32.51, 32.52, etc. Both are 3/8 IC triangles, screw down, neutral rake, 7* relief.
If the top edge of the shoulder were stoned down a bit then the thicker insert might seat. Don't see any reason why not, though it might ruin them for use with the original 32x inserts - small loss!
- Glenn -
01-10-2006, 01:52 AM #12
Aluminum
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Hi guys,
Watch using the ANSI Insert chart. Some of the info does not carry over to the newer ISO stuff. Example: The ANSI does not even list a "T" or "W" in the fourth place. On a ISO chart they mean screwdown insert with or without chipbreaker. ISO usually have smaller holes and 60° countersinks also.
When we duplicate carbide inserts in High Speed Steel, we run into this problem all the time.
Smootz-One thing to watch for in a holder is that the insert pocket has the same angle as the insert. This (Relief) angle is the angle running around the insert.
Good Luck
Mike
- [machinist] Indexable Lathe Tooling Info, Lawrence London, 01/29/2013
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