Author Topic: Insert Madness.....Help Please!  (Read 7444 times)

Offline vtsteam

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Insert Madness.....Help Please!
« on: February 15, 2022, 01:11:45 PM »
I have been generally an HSS guy on my lathes. Some time ago I did buy a 1/4" carbide insert turning set, from I don't remember where. I have gradually used up the inserts that came with the set and have one beat one left.

I have never been able to figure out what replacement type it is. I have found explanations of the insert numbering system(s), but they all vary and often don't match the dimensions I have. It seems a Babel of dimensioning systems with inches and 1/8"s and decimal representations of even that, and metrics thrown in. Inscribed circles, screw countersink tapers.  :bang: I've 3 times ordered inserts that don't fit.  :hammer: I'm giving up DIYing any sense to this insane non-system....and asking for your help. Please, sirs and madams, etc. What do I have? Thanks in advance!!!

It is triangular.
It takes a countersunk T6 torx screw. Threaded part is 2.07 mm dia, head is 2.99mm dia.
It has chip breaker gutters on three sides on one face
A side measures 8.92 mm long (.351" and that's measured with a caliper from the radiused and possibly worn tips).
It is exactly 2.54mm, (.100" thick)

What is it????
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg


Offline John Rudd

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Re: Insert Madness.....Help Please!
« Reply #2 on: February 15, 2022, 02:35:28 PM »
Steve, what you are describing sounds like TCMT tips....the first letter describes the basic shape...D = diamond, T is triangular....

Best if you look on one of the websites for the makers of these things, as its a nightmare deciphering the annotation....
eccentric millionaire financed by 'er indoors
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Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #3 on: February 15, 2022, 03:15:08 PM »
Thanks Kayzed. But I believe those are the a little bit larger ones I have bought by mistake three times! (They say repeating the same mistake a second time and expecting a different result is a sign of insanity. Not sure abut what it means to have done it three times!  :loco:)

Thanks John. I'm afraid I've spent the entire morning trying to visit mfr sites and decipher insert codes and it just hasn't worked. It wouldn't be so bad if I already had a number, but this working backwards to try to get a number is just fruitless. I know the dimensions of what I have, but it doesn't match up with the systems I find.

For instance the thickness of .100" Can't find that. Supposedly the standardized mfr.'s insert numbering system for thickness works with old measure 1/16"s, where you are supposed to find the thickness in sixteenths, expressed as two decimal digits. So .100" would be 1.6. Well okay, but then I only find actual inserts on Ebay listed as 1.5.

And for the width, well that's supposed to be in eighths, as two digits, but it's not the width of the insert, but an inscribed circle around the insert.

 :doh:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #4 on: February 15, 2022, 03:34:48 PM »
I've looked all over for the tools I have, and they haven't matched the type of 1/4" tools available everywhere these days. But just now I found on Amazon, these, and they look just like my set:

https://www.amazon.com/Anytime-Tools-Indexable-Carbide-Insert/dp/B0087R9OUA

And they mention the inserts -- "TCMT090204", and they are available also on Amazon!

(Man I really hope those are the same as mine, or it will be my 4th set of wrong inserts.)
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vintageandclassicrepairs

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Re: Insert Madness.....Help Please!
« Reply #5 on: February 15, 2022, 04:27:14 PM »
Hi
I read that insert as having a 9mm side length, 2mm thick with 0.2mm corner radius ?

John

Offline awemawson

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Re: Insert Madness.....Help Please!
« Reply #6 on: February 15, 2022, 05:02:26 PM »
Thickness, and cutting height aren't necessarily the same. This got me confused when I had inserts from some random source that varied slightly from the one I was trying to match.

I was just measuring thickness with a vernier where the central hole was, but when I started measuring thickness at the actual cutting edge (they had a pronounced chip breaker groove) it all started to make sense!
Andrew Mawson
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Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #7 on: February 15, 2022, 06:47:03 PM »
Hi
I read that insert as having a 9mm side length, 2mm thick with 0.2mm corner radius ?

John

Interesting John. I guess that is maybe how they approximate it in the name???

I found one mfr. dwg of a TCMT090204 and it's got a 9.60mm projected side length, it's 2.38mm thick, and has a 0.2mm corner radius.

And  the one I'm trying to replace measures 8.92mm side length, 2.54mm thick, don't know corner radius. I guess the side length is close to 9 if you allow for the radius.

This site is the one that really confused me. Maybe there's a couple different ways of naming these things:

https://www.ctemag.com/news/articles/understanding-identification-system-indexable-inserts

especially:

Quote
5. Size

The fifth position is a significant one- or two-digit number indicating the size of the inscribed circle (I.C.) for all inserts having a true I.C. such as Round, Square, Triangle, Trigon, Pentagon, Hexagon, Octagon, and Diamond. This position designates the number of eighths of an inch in the nominal size of the I.C. It will be a one-digit number when the number of eighths of an inch in the I.C. is a whole number: 1 – 1 ⁄ 8"; 2 – 1 ⁄ 4"; 3 – 3 ⁄ 8"; 4 – 1 ⁄ 2"; 5 – 5 ⁄ 8"; 6 – 3 ⁄ 4"; 7 – 7 ⁄ 8";

8 – 1"; 10 – 1-1 ⁄ 4".

It will be a two-digit number carried to one decimal place when it is not a whole number: 1.2 – 5 ⁄ 32"; 1.5 – 3 ⁄ 16"; 1.8 – 7 ⁄ 32"; 2.5 – 5 ⁄ 16".

and:

Quote
6. Thickness

The sixth position is a significant one- or two-digit number indicating the number of sixteenths of an inch in the thickness of the insert. It is a one-digit number when the number of sixteenths of an inch in the thickness is a whole number: 1 – 1 ⁄ 16"; 2 – 1 ⁄ 8"; 3 – 3 ⁄ 16"; 4 – 1 ⁄ 4"; 5 – 5 ⁄ 16"; 6 – 3 ⁄ 8"; 7 – 7 ⁄ 16"; 8 – 1 ⁄ 2"; 9 – 9 ⁄ 16"; 10 – 5 ⁄ 8".

It is a two-digit number carried to one decimal place when it is not a whole number: 1.2 – 5 ⁄ 64"; 1.5 – 3 ⁄ 32"; 2.5 – 5 ⁄ 32"; 3.5 – 7 ⁄ 32".

 :loco:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #8 on: February 15, 2022, 07:17:20 PM »
Thanks Andrew and John R,

Well, new inserts sent for.

I was thinking, since I have 3 sets (30) of the wrong, slightly larger, inserts, maybe I ought to use them to make my own insert tools to fit. They are 60 degree triangle, so I guess threading, and boring bars are possible, besides some 3/8" sq. lathe tools -- a set of which I don't have. So I checked the screw size, and it's an M2.5. Then I sent for 50 M2.5 insert screws with Torx screwdriver ($6.99) on Ebay, and a M2.5 x 0.45 tap and die set for12 bucks. Could be a lemonade from lemons situation.



I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #9 on: February 16, 2022, 03:28:15 AM »
Mostly OT:

I have been trough this....Went from brazed tips to HSS, to cheap indian 7 piece insert tool set, that had four different inserts. Before I found out that the boring bar, threading tool and groving tool was no good, I kept ordering the "original" indian inserts that shater when they touch steel. Britle at any speed. I still use two holders, because luckily they had standard 9 mm nominal ISO CCMT pockets. First step to success was to ditch useless holders (noname proprietary inserts or pocket was rough and would stress even a god insert). Then I ordered some swiss inserts and they actually worked as promised. Not cheap at 3-5 EUR apiece (local industrial toolshop has discount once a year, I buy a box once a year).

I got that pissed of cheap holders that I ordered set of Maier boring bars and they actually worked really well. They also had a coolant hole and I used spray can plastic "sleeve" to spray canned coolant trough boring bars when cutting blind holes or extra difficult materials.
https://maier-tools.de/epages/Maiertools-Shop.sf/en_US/?ObjectPath=/Shops/Maiertools-Shop/Categories/Drehen/WendeplattenDrehwerkzeuge/Bohrstangen/Positiv__Bohrstangen/Form_C/SCLC
There are some xtra complications on boring bars and apropriate inserts, but I got the bars that use standard ISO CCMT06 inserts, but on a funny angle, you need fairly positive insert.

I also ordered a nice small external CCMT turning holder, but while it is nice, I found out that many mid priced chinese/taiwanese around 20-30€/piece work almost as good.
https://maier-tools.de/epages/Maiertools-Shop.sf/en_US/?ObjectPath=/Shops/Maiertools-Shop/Categories/Drehen/WendeplattenDrehwerkzeuge/Aussenhalter/Positiv__Aussenhalter

I was considering triangular inserts, because they have one extra corner (tempting for economy) but the good holders were taiwanese 70€ apiece and due to geometry I would have needed more holders and more different type inserts....I ended up CCMT06 (and CCMT09 because few old cheap holders I had bought) for general use. I augemented that much later with SSSCR 1212 F09 holders for roughing and camfering. That isert has four corners....not really sure if that is strictly necessary, but they work good and have more robust edge than CCMT but way less flexible. I have been breaking these expensive inserts too (stupid really, 0,4 mm r is minumun for general use and 0,8 mm r for roughing) but generally the expensive inserts really outlive the cheap ones to the extent, that after the initial down payment they have come more economical and stress free.

For grooving, threading and such I bough some second hand Secos, but really hard to find right inserts for them. Sort of white elephant. Sometimes I fondle them, but use very seldomly. I have some rare inserts for them and they can be modified to suit some extra awkward work if the need arise.

I haven been ordering infequently some holders and inserts from Mesa tools:
https://www.mesatool.com/product-page/1-2-thread-grooving-tool-id-od

Those are great. One holder and you can assemble insert on three different postions. They are actually very clever, because they offer flexibility for left/right hand external grooving and left/right had internal groving plus you can use make rounded edges or O-ring grooves. The inserts are not top quality, but perfectly adequate for me.  All hardware is standard and Jim always answered my questions. I can recomed them. The tool holder is sort of simple and you wonder if at 40 USD is really that good, but made by a small company in western country and it just works without any waff. Well worth it.

There is a learnig curve on insert tooling and use. Pretty opposite of HSS, but no grinding (necessary/usually) and no cooling (usually) and flat out rpm until you get least blue or violet swarf out of it.

Offline chipenter

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Re: Insert Madness.....Help Please!
« Reply #10 on: February 16, 2022, 03:35:39 AM »
you could also modify your exiting holder by taking 20 thow off each side , the lead in angle is normally 5 degrees , don't take to much as you want the screw to pull into the corner .
Jeff

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #11 on: February 16, 2022, 08:46:59 AM »
Thanks Pekka, that's very good information, and I imagine you're right on all counts.  :thumbup:  :beer:

Jeff, I think I'll leave these as-is, and just make new ones for the larger triangle inserts.  :zap:

My main purpose in using carbide at all is in dealing with sand and scale on iron castings. I'm starting to realize that (like Pekka said) I should be looking for .8mm radius, not .4, and in the older system C2 not C6 for that.

Probably though, it would be even smarter to just first go over the to-be-machined surface of castings with a hand disk grinder first, and if down to clean metal, just switch to HSS!

Well, of course, can't do that with internal surfaces.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #12 on: February 16, 2022, 09:02:57 AM »
I am not seasoned with sand castings, but I found it usefull to "get under" the hard surface. If lathe will manage deep enough DOC the good. And to have a swipe with angle grinder under the "skin" at the start will help to make the first critical cut. I found it useful just a touch with angle grinder, right at start would help a lot.

For sand casting I used cheapest ever brazed tooling I got...my friend bought a pallet of old brazed lathe tooling, they looked pretty similar all. Ugly tip on a 3/4" shank and that's it. He has few lifetime supply of those.

I might be reluctant to use expensive tips for plowing through cast skin. There will be hard spots.

Offline vintageandclassicrepairs

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Re: Insert Madness.....Help Please!
« Reply #13 on: February 16, 2022, 05:59:54 PM »
Hi Steve,
I find the 0.2 and .4 radius tips too easily damaged in normal use, I keep a few for use when needed to make tight radii on stressed parts such as collet grooves on engine valves
A way to use up odd tips that you do not have a holder for is to braze the tips to bits of square bar, you may need to angle the tool end of the bar to provide cutting edge clearance
I have re heated them and turned the tip to a fresh point and they still seem to work well
A week or two ago I needed to make an oddball 20mm metric nut but found that my internal threading tool to suit the pitch was too big to fit in the bore !! I hacked one end of a piece of 5/8 square bar down to fit the bore and brazed on the threading tip. it got the job done without waiting weeks after ordering one! The nut is made from EN24 fits the end of the crankshaft of an 8hp De Dion (1902) and holds on the clutch

John

Offline krv3000

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Re: Insert Madness.....Help Please!
« Reply #14 on: February 16, 2022, 08:06:00 PM »
 hi right just sum tip's :D when getting tooling sum tool bit holders have printed on. Numbers this Number is more than likely a Number that they have made up so you only get their tips. with the net its possible to cros refrains this Number to the conmen ISO standard  ones you have got the Number say its TCMT stamp or engrave this on to the tip holder then you will always have it on hand.   right then you need the finish code and I can see people saying  wat??   right just say all your tooling for the lathe uses TCMT tips right but wat material are you going to turn I.E will it be brass. steel . stanles steel cast ion and so on I see and hear so many complaints regarding the finish their getting this can be dawn to two things Ronge tip or witch will be more common Ronge steel the finish cod refers to wat type of materiel your turning with that tip and also the finish on the part ones dune for example my tips are CCMT but I have 4 boxes of them yes their all the same type but one box is for steel one box is for cast ion and one for stanles steel and brass if you look on the back of a box of tips their shod be a label with a culler code and a prefix leter the culler and leter refers to wat type of material the tip is made to cut. yep I have to got tips off the net witch turn out to be crap in the ad it may say general purpose but wat for ???   any way hop this helps

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #15 on: February 16, 2022, 08:32:42 PM »
John, cool!  :clap:

Bob, thank you kindly for the advice. I'm sure, now that I have probably ordered the right size of insert, that it's going to be quite wrong kind for roughing out the iron sand castings I'm making!

Oh well......

Also, I notice that in this shape and size insert, there doesn't seem to be much available variety for different metals. I have a feeling these won't last long or work well for what I will probably use them for.

I've also read a comment somewhere else that for roughing, cast iron, they actually liked ordinary cobalt lathe tools (Cobalt 8% or M42 HSCo) nearly as well as specialized carbide inserts. That might be the way to go for me.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline krv3000

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Re: Insert Madness.....Help Please!
« Reply #16 on: February 17, 2022, 05:21:39 PM »
hi well when I'm ruffing out castings I use brazed tungsten tip tools   I don't by them I make my own up my tool holders for the lathe hold 12mm tooling so I get  12mm stock and grind the relief angle on the end then I braze  a used tungsten tip of one of the big milling heads at work then with the ad of a green grinding wheel grind it to shape    :nrocks:

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #17 on: February 17, 2022, 09:12:21 PM »
Sounds good, Bob. I don't have access to big milling heads for tips, but I suppose I could just order a brazed Ebay lathe tool in C2 and see how well that lasts. I have a few old C6 tools someone gave me, but those chip easily. I think C2 might last better for this. I do have a green wheel.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #18 on: February 17, 2022, 09:34:36 PM »
Spotted a C2 brazed 3/8" AR lathe tool bit on Amazon for under 3 bucks, so I had to give it a try. Ordered three at that price. I'm curious to see how C2 holds up.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #19 on: February 18, 2022, 02:23:05 AM »
Spotted a C2 brazed 3/8" AR lathe tool bit on Amazon for under 3 bucks, so I had to give it a try. Ordered three at that price. I'm curious to see how C2 holds up.

By looks and description they look very close to tools I have been cleaning up cast iron. They need a little sharppening often. Just a little careful push on bench top grinder with a cheap greengrit or diamond wheel and quick turn to make good radius. Radius is too big if it is bigger than DOC and too small if the breaks way before dulling. keep clearance angles small to support the tip fully. Sounds like you will not be taking grazy cuts, then you don't need all out clearances, just enough to avoid rubbing.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #20 on: February 18, 2022, 08:51:25 AM »
Thanks Pekka, will do and I'll let you all know how they work out for the purpose.  :beer:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline mc

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Re: Insert Madness.....Help Please!
« Reply #21 on: February 20, 2022, 06:49:01 PM »
Stupid question, but you have checked for a part number on the holder shanks?
Usually insert tools have their holder number etched/printed on the side of the shank.

If your holders use TCMT inserts, then the holder model number should start with ST.


The issue with insert tooling, is although there is quite a bit standard and common range of holders/inserts, there are also a lot of manufacturer specific holders and inserts, aimed at specialist applications.

Personally I'd advise if buying any insert tooling, make sure it's to one of the generic standards.

Also, given your intended application, find some inserts designed for interrupted cuts. There is a very wide range of insert materials and geometries, so try and find something suitable for your trying to do, otherwise insert life will likely be very short.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #22 on: February 20, 2022, 10:22:01 PM »
Hi mc, no nothing was printed on the side of the tools other than AR or AL, etc

I do know the original insert part number now (TCMT090204) C6 and also know that ideally I'd want a .8mm radius(TCMT090208) and C2 carbide for my application -- but hard to find that combo. I have been successful now with original replacement inserts with careful and relatively fine passes on interrupted cuts with my sand castings.

But looking forward to trying out the other tooling ordered as mentioned earlier in the thread. I actually think that the cheap-as-chips brazed C2 sticks I mentioned a couple posts ago might be the ticket for roughing these castings. We'll see, and report back.  :dremel:

Iron, casting below machined from rough with replacement original "wrong" C6  .4mm. Didn't break a corner on it.......so far. But it was slow going.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline mc

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Re: Insert Madness.....Help Please!
« Reply #23 on: February 21, 2022, 11:59:38 AM »
Carbide grades for inserts do vary between manufacturers, as there is no standard.
C2/C6 is pretty meaningless in the grand scheme of things.

Now you know the insert type and size, you really need to do a bit research into what different suppliers offer. Most will give recommendations for different materials, and different cuts.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #24 on: February 21, 2022, 02:12:26 PM »
Well I don't "really need to". One "might want to."
But actually nope.

While it doesn't specify composition, the C system does specify intended function. Like the name High Speed Steel. Useful enough for my purposes without specialist consultation.

C grades classification
C-1 to C-4 are general grades for cast iron, non-ferrous and non-metallic materials
C-1       Roughing                     
C-2       General Purpose
C-3       Finishing
C-4       Precision
Steel and steel alloys - these grades resist pitting and deformation
C-5       Roughing                     
C-6       General Purpose
C-7       Finishing
C-8       Precision
Wear Surface
C-9       No shock
C-10     Light shock
C-11     Heavy shock
Impact
C-12     Light
C-13     Medium
C-14     heavy
Miscellaneous
C-15     Light cut, hot flash weld removal
C-15A  Heavy cut, hot flash weld removal
C-16     Rock bits
C-17     Cold header dies
C-18     Wear at elevated temperatures and/or resistance to chemical reactions
C-19     Radioactive shielding, counter balances and kinetic applications

 
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline mc

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Re: Insert Madness.....Help Please!
« Reply #25 on: February 21, 2022, 03:24:50 PM »
The C grades are for brazed tooling, not inserts.

To give you an idea, I've attached a photo of one brand in one of my regular suppliers catalogue. There is no mention of C grades.
(I did look for a PDF, but the only PDFs I can find are for insert types/sizes/grades with no explanation of the grades)
Every manufacturer will usually have their own grading system, which is why if you want to find the most suitable insert, you need to research what each manufacturer produce.

As well as the grade, there will also be various chip breaker options, although it's more common for the insert grade to also cover the chip breaker option now.

Then there is the option of other insert materials, like PVD (diamond - more suited to softer non-ferrous or non-metallic materials), CBN (Cubic Boron Nitride - more suited for tough/hardened materials and demanding cuts), and ceramic inserts (similar applications to CBN).


But having had a quick look at what options are available in TCMT09 size, the options seem to be very limited.
Personally, I'd suggest getting a SCLCR(or L) (or another style of holder depending on how you'd like to approach work/take cuts) that takes CCMT inserts, as even in the small 06 size, the insert options are far greater. Or if you can fit a bigger holder that takes the bigger 09 inserts, the options seem to increase more.

You do only get two usable corners on the rhombic inserts for any given holder (you can get other holders that allow you to use the larger angle corners - SCBCL/R), but they are a more popular inserts shape than triangular, so more options exist.
For the TCMT inserts, options don't really expand until you reach the size 16 inserts.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #26 on: February 21, 2022, 05:49:55 PM »
The C grades are for brazed tooling, not inserts.

mc thanks, I've got fancier insert tools, but I started this thread to try to identify what size inserts my bottom of the barrel el cheapo 1/4" lathe tools took. I think of them as nearly expendable rough cutting tools, and as soon as they get through the scale, sand inclusions, interrupted cuts, and skin chill, I will likely switch to hand ground HSS tools.

I understand that your supplier has an array of carbide coatings sizes configurations and base materials. But I like things simple and basic and traditional. And the projects I produce are the same kind of thing. For me that's the part of the machining hobby I'm attracted to.

To give you an idea how cheap and reactionary I am, for carbide inserts, this is my supplier's catalog, and yup, they do stock indexable C2 inserts, not just brazed C2:

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=c2+carbide+inserts&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=c2+carbide+inserts

Of course I have no objection to brazed C2 tooling -- as mentioned earlier, I just ordered three of them to see what they will do when pitted against one of my home castings.

I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #27 on: February 22, 2022, 05:49:57 PM »
Today I received the three $3 Chinese 3/8" C2 carbide brazed lathe tools, so I put one to work right away. It did great, taking off rough surface iron from the sand cast hot piston in an interrupted cut (~ 0.125" eccentric) with no problem. It seemed to have almost no nose radius and I haven't ground it on the green stone yet, but it performed well enough anyway. Last pass looks good and finish consistent with the first. No chipping or breakage and it looks like no wear.

I was cutting .010-015", didn't go deeper mainly because the casting was unsupported by the tailstock. I didn't want to jar it out of the three jaw where I was holding it by the bore. I wanted to reduce bore eccentricity, rather than that of the surface. That just makes boring easier.

I'm very pleased with these inexpensive brazed tools for my particular purpose. A definite bargain.

Below are the roughed out hot piston (taller one) and the cold piston, which was done earlier with a carbide indexable insert tool. The brazed tool was faster to finish the job, even though the casting was longer.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #28 on: February 23, 2022, 03:50:48 AM »
Happy to hear of your good results.

My success rate with cast iron with brazed inserts has been high too. Pretty much all brazed inserts russian/chinese orgining seem to work most of the time as long as they are on small shank. I have met some pretty big russian inserts that were like 20 mm square and really thick. They were practically impossible to sharpen to a keen edge. I was told that they are really good on positive angle and DOC over 5 mm....our roughing is industrial finishing. Only systematic problem I had with brazed "hobby" tools of indian origin, markings were good but they would crumble. Two sets of them.

Inserts can be very good too, but there are two problems:
1: Although pretty much all brazed carbide tooling works I have had less than 50% success rate with cheap inserts. Some claim that they had better luck, but for me it does not work out to buy cheap inserts. Some relatively cheap tool shanks work fine.

2: The whole insert business is a jungle. After you have found the correct insert geometry that you actually screw into tool shank you are into a treat. There are different grades of base material, coating, nose geometry, chip breakers and what not. And all that is really really important! Some inserts are optimised for certain task. Remove the hell out of the stainless unobtanium steel, pressurized air as coolant and tip life of 15 min on really rigid machine.

And insert + shank is pretty expensive down payment. You need to know what you are getting. Then it works fine. THis is contary to brazed carbide...you buy wrong or dud and you loose 8 USD. Big deal. Usefull insert shank costs 20-60€ + box of inserts starts at 40 €....it is great when it works, but my income does not allow repeated mistakes.

And then there is skewed scale of how different machines we have. You just can't assume that hobby roughing is industry finishing. True to a certain extent but not exactly. Industry might be able to use much smaller tip radius, because their machine is more rigid, controlled materials and coolants. Hobbyist may need to compromise on pretty much everything else but time. We can't and we don't need to shift 3 kg of swarf in few minutes but some inserts are designed to do that.

Pretty much what I know is that for aluminium you need uncoated and "polished" inserts, some of them work for stainless steel and free cutting steel too. For most iron material I use "general" use insert that is PVD coated. And I stick with them. There are so many insert/shank/grade/chipbreaker combinations that you can get lost to them.

Confession time: I have some GRP500 cast ends...that is pretty high tensile spherical cast iron. I use PVD coated general use inserts after I get under the skin.

https://online.lamina-tech.ch/catalog?item=T0001889

There are shitload of fake inserts floating on the usual sites. I buy these only from the local industrial tool distributor that makes me jump trough hoops to buy them, but original works for me. I have seen copies and they are hard to recocnize by looks, but all effort is used for looks, not for function.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #29 on: February 24, 2022, 08:57:48 AM »
I agree totally, Pekka, re inserts for home shop use. Good to hear specifics of what you find useful on a practical scale for the materials we generally use.  :beer:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #30 on: February 24, 2022, 09:44:38 AM »
I looked up that insert, Pekka, and for cast iron of 2.4" (60 mm) dia. -- my cylinder--  the minimum Vc  listed is 160 M/min. (525 sfpm). If my calculations are correct it would require as a minimum spinning that piece of iron at 875 RPM to take a cut.

That's not going to work.





I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #31 on: February 24, 2022, 10:16:53 AM »
They are industrial inserts and recommendations are designed for best utility and often for 15 min duration. I look primary for min/max. DOC, usually really can't go under r. BUT I go under cutting speed and on feed. Just don't have the spindle power and machine is not rigid. Main thing that surface finish is good enough and swarf behaves half decent. Sometimes I can tell that chip does not break right, but if that is the only problem, then fine. Took some practice.

Main reason I use carbide inserts is that alternative would be HSS: 1) Grinding is a hot work (Fire hazard), 2) coolant/lubricant. For some people this is not problem.....I use carbide dry. Then again, I am fine with threading tap and I have one cutting fluid for aluminium and one paste for iron metals. I use HSS when I have to....I guess I am bilingual now on cutting tools.

But lathe and milling machine spins cutting fluid pretty energeticly all over. Blue to red fast flying swarf from a happy carbide insert has it's own set of problems....I have been doing some boy band dance moves to shake it off.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #32 on: February 24, 2022, 10:38:38 AM »
 :) I get you on the dance moves!

Same here also on machine rigidity, spindle power and coolant.
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg

Offline PekkaNF

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Re: Insert Madness.....Help Please!
« Reply #33 on: February 25, 2022, 12:53:02 PM »
Today I YT recommeded me This Old Tony Video about carbides. Better than my ramblings:


Although, he forgot to tell about the utility of brazed carbide tooling with cast iron....but othervise spot on.

Offline vtsteam

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Re: Insert Madness.....Help Please!
« Reply #34 on: February 25, 2022, 07:29:41 PM »
Thanks Pekka, excellent video, particularly from the home shop perspective.  :beer:
I love it when a Plan B comes together!
Steve
https://www.youtube.com/watch?v=4sDubB0-REg