Cheap (Chinese?) Carbide Tips

Discussion in 'Tools' started by MRA, Jul 5, 2018.

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  1. Jul 10, 2018 #21

    Dubi

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    First rate post. That is exactly how it is. One thing I have noticed is no one has made a comment about using different types of coolant or cutting compounds.

    I once tapped a piece of aluminium, as a test, using paraffin and then using Tapamatic. The improvement with Tapamatic was amazing. Coolants and cutting oils make a big difference.
     
  2. Jul 10, 2018 #22

    DJP

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    I don't push my carbide cutters hard enough to justify coolant systems and my experience with them in big shops is that they stink. I do use a cutting oil and it smokes when things get hot on the machines. When cutting threads I use Chromatap. I bought a gallon decades ago and I need to use it up before trying something different.

    I did experiment with a mixture of equal parts kerosene, Varsol and Automatic transmission fluid. A buddy who works in aluminium says it is a good machining fluid in his production shop and inexpensive too.

    Cutting fluid is wonderful but you don't need a lot of it.

    My thoughts for the discussion.
     
  3. Jul 17, 2018 #23

    Wizard69

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    Interesting discussion, most of my machining is related to production machine repair and almost all of the tooling we use is purchased from a local supplier. I have no idea where some if it comes from, could be the USA, Israel or China for all i know. How well any of it works depends upon applying the right cutter to the application. Even the coatings can be an issue as some do not work with Aluminum very well at all.

    So there is the issue of using the proper cutter for the task at hand and the equipment it will be used on. You really need to take care to make sure that the geometry, rake, coating and other parameters makes sense for the work you expect the carbide to do. An insert design for a lathe with 25 HP at the spindle doesn't make much sense on a hobby engineering lathe. In the hobby realm you need to do your research.
     
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  4. Jul 17, 2018 #24

    goldstar31

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    I re-read Conrad Hoffman's excellent dissertation in his Conrad and Jeanne's Messy Basement.
    He gives a relatively clear explanation of why some of these carbide inserts are unsuitable0 as Wizard69 suggests because of lack of horse power and the 'wrong negative cutting angles'.

    Hoffman goes on to explain why an insert will not take a an almost imperseptical cut whereas a quite normal bit of his tooling will do it.

    Finally, he suggests how carbides CAN be honed to do precisely what we oldies can do with his- and sometimes ordinary carbon steel.

    Of course, it may appear as heresy to some but do recall that many of the models which are being attempted were made using hss and carbon steel tools.

    Thanks again Wizard69 for expanding the discussion.

    Me? I'm at the stage where most of the rust and whatever has been removed from my version of Dennis Chaddoch's Quorn which if read correctly , gives an insight into the first Door Westbury mill which- clears throat- made his famous v12

    Regards

    N
     
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  5. Aug 10, 2018 #25

    rockets

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    I have been using tips from Bangood after seeing them recommended on Doubleboost's Youtube channel (no affiliation to either). I have to say that they work just as well as anything else I've used. I've cut a variety of materials, they'll cut EN16, various grades of aluminium and brass without issues. Haven't had any chipped or broken edges either.

    Incidentally, I had a box of Kennametal tips which looked identical, and even said contents made in China on the box. I draw some inference from that.

    Rockets.
     
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  6. Aug 10, 2018 #26

    goldstar31

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    As you are more or less a newbie but with a 3 in 1 lathe, it would be a easy matter to make up a 'puck' as suggested by Hoffman.

    Thinking about materials as cutting tools, I used broken glass from WW2 bombed out houses to make 1/72nd scale models and improved safety razor blades in glass tumblers to make obeche and balsa models. One of my old associates made a Quorn t&c from solid not castings and amongst his workshop tools were things like scrap hexagon keys as lathe tools and motor cycle spoke as boring bars.

    Hoffman was merely improving the Holzapfell stuff from Maudsley days.

    You might be pleasantly surprised-- and saved a lot of money

    Regards

    Norm
     
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  7. Aug 10, 2018 #27

    BIGTREV

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    I use cheap Chinese Carbide Tips, but I only do shed work(nothing to technical) and I luv em, I buy the cheapest l can find on ebay, or Aliexpress.
    Virtually everything I learnt at college in the 1970's, about speed/RPM has gone out of the window
     
  8. Oct 19, 2018 #28

    backyard_cnc

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    My cheap Chinese carbide insert threading tools actually outperform my expensive American made crap. 2 carbide inserts alone for my American tool cost about the same as I paid for my Chinese toolholder and 10 inserts. The American inserts are brittle and easily chipped so I rarely finish a project on one edge alone yet the cheap Chinese inserts just last and last! I would suggest that no one should dismiss these inserts or tools on the basis of price or country of origin!
     
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  9. Oct 20, 2018 #29

    biqut2

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    I am a machinist and run various inserts daily on multiple lathes and mills. The majority of our tooling is Sandvick, we also run Secco, kennametal, HSS and hand ground carbide. In my home shop I use tooling from China exclusively. I would rank the tooling as follows:

    1. Kennametal/Secco
    2. Everything else
    3. There are cheap and quality versions of everything

    If you purchase the abosolute cheapest insert you can find that's exactly what you'll get. In my experience a lot of quality can be obtained from China. For example I have compared tnmg22 inserts;

    China: Holder $10/Inserts $3 each
    Sandvick: Holder $150/ inserts $25 each

    End result is that the tooling from China performs equally or actually better in some applications, and at a fraction of the price.

    Now I have also tried some of the $6 holders and $1 inserts and found them to be very much inferior.
     
  10. Oct 20, 2018 #30

    Ozwes007

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    Just my 2 cents worth. I use carbide inserts nearly everyday at work in lathes and mills, cutting anything from bearings to 1040 grades steels, plastics, aluminium, brass, bronze etc etc. in most cases I use Iscar, or kenametal inserts.
    Fact 1 is that a better grade(not quality) for the material and cutting style will normally last me about 8 hours of cutting per tip(triangle double sided insert has 6 tips)
    Fact 2 is that I can with ease get dimensions to within 0.02 of a millimeter on most ferrous and non ferrous materials. Plastic it depends on the hardness.
    Fact 3 is that taking a small cut with accuracy to .02mm(0.05 or lower) with carbide requires high speeds and a high rake cutting tip
    Fact 4 is that carbide tips go down to 0.2mm radius tips(you can get lower$) and the reason is that carbide is a sintered material and the quantity of carbide to binder is altered to give different grades this means that the tip will fail if the radius is to small.
    Carbide used in a wood mouldings head is as sharp as HSS and lasts so much longer in use that HSS is considered obserd. This carbide is very brittle. That carbide used in milling machines to cut raw cast iron is extremely tough, but it can’t be honed or sharpened to a fine edge.
    Usually with cheap carbide tips you will find they are more binder than carbide so sharp, honed and small radius inserts rarely work well. And as always the general rule is the depth of cut should be just over half the radius and the feed should be around the radius of the tip(alter to double and half to change between fine feed and heavy cuts)
    And as always understanding your tooling is half the battle, remember carbide doesn’t actually cut material like HSS, it shears(rubs) the material off. That’s why it is so shiny when it is done right.
     
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  11. Oct 21, 2018 #31

    lennardhme

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    Interesting subject, & one that I think should be encouraged - there are always new folk entering the hobby who could learn a lot from such discussions.
    For my part, I spend probably more time than most sharpening end mills, as I am the allocated end mill sharpener using our club's machine. This does not make me an expert, but I do spend a lot of time examining bits with a magnifying glass.
    My findings are that after sharpening, carbide end/slot mills, are equally as sharp as HSS counterparts. The difference is that after a short period of use, carbide mills have a noticeable, but very slight wear, on their cutting edge,[using a magnifying glass] whereas HSS usually does'nt.
    From then on the change in wear pattern is quite noticeably reversed. HSS has a gradual dulling of cutting edges, until the tool becomes noticeably blunt. Wear on a carbide bit is much slower, & it can be used very much longer before the need for sharpening becomes evident. I put this down to the much harder material suffering from microscopic chipping rather than wear.
    It is this 'grey' period that causes me to prefer HSS [as a hobbyist, & in most cases] over carbide, because the deterioration in finish is sometimes hard to pick with carbide.
    Just my findings for what they're worth.
    cheers, Lennard.
     
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  12. Oct 21, 2018 #32

    mohavegun

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    I use a lot of low priced and quite often Chinese cutting tools. I find that for the most part they hold up quite well. There are those that are not properly sharpened or do not fit exactly as they should but generally speaking they are usually quite good.

    The problem I have with running any carbide tool 'slow and easy" is that the lower speeds tends to damage the tool much faster and worse than running at high speeds. I have one job that repeats in my shop where I cut .065" deep and 3/4" diameter and remove about 30 square inches of material from the surface of heat treated 4140 sheet steel (Rockwell C 40 -48). I am using some lower cost S. Korean made inserted end mills (3/4" dia flute) and I see very good tool life in the 150 sfm (800 RPM) range but the tools tend to break down when I run much slower than that and I have pushed these tools up over 250 sfm (1500 RPM) without noticing excess wear or failure. I also have noted that too light a feed rate is detrimental as well and the best finish and tool life are both found at somewhat elevated feed rates. I do these cuts on a 5 HP manual milling machine with water based coolant and power feeds. In my world I like to see 15 to 20 parts on a set of insert edges or 30 to 40 parts per set of inserts. Sometimes I can get over 50 parts on one set of edges! I bought these tools for about $100 US with 10 inserts, a similar tool by Kennametal is about $190 US and inserts cost about $12 each. I rest my case!

    Other factors affect carbide tool life, especially interrupted cuts, as when you cut through a slot or hole, coming out of a cut then slamming right back into the cut will very quickly take out your cutting edge on most carbide tools, Cobalt and High Speed Steel does better here.

    The tools I tend to shy away from are made in India, I have lost faith in Indian carbide tools.

    About 1/3 of the later model machines and cutting tools in my shop are of Taiwan, China or Korea origin.

    I am not impressed with Chinese lathe and drill chucks!

    I do have good comparison tooling, I use a lot of Kennametal inserts and USA made carbides.

    As for cheap hack saw blades, I don't! I have 3 band saws and blade welder so I cut up band saw blade for my hacksaws and get the blades cheap that way, I use Lennox mostly and it holds up extremely well in hand sawing operations!

    I have called myself a machinist since I started my apprenticeship back in 1968, which was at least a couple of days ago!
     
  13. Oct 21, 2018 #33

    tornitore45

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    More like a plow or even more accurately like a bulldozer moves earth.
     
  14. Oct 22, 2018 #34

    bazmak

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    Good post Leonard, most model engineers will use whatever they have.I use cheap carbide most of the time
    if I am concerned about hard spots ie cast iron or welded parts simply because they last longer.A few seconds with HSS on the wrong material
    will remove the cutting edge instantly.My main concern with carbide is chipping especially with interupted cuts.But the tips can be refreshed
    a few times with a diamond wheel therefore prolonging life. For better finish on most non hard material then my choice would be HSS
    I also have a large stock of rebar which I use if I need a high tensile part.I usually rough them down with cheap carbide tools and finish
    with HSS. In my youth carbide was very expensive and I was told that RCt could not be sharpened That I now know is not the case
    In general I now use what I have and what suits the application best.No hard and fast rul;es
     
  15. Oct 22, 2018 #35

    lennardhme

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    Thanks bazmak,
    I'm the same- only use carbide when required. Its horses for courses.
    I have since viewed various carbide & hss endmills under an electron microscope. The hss develops a polished rounded edge as it blunts. The carbide is quite different in that the cutting edge is serrated looking, which are in fact tiny chips; too small to see with a magnifying glass, at least with my tired old eyes. The chips eventually develop into a 'wall ' which, due to its hardness, still 'cuts 'as others have mentioned.
    Happy machining,
    cheers Lennard.
     
  16. Oct 22, 2018 #36

    goldstar31

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    I don't wish to interfere but as I live in the UK, there is an apparent problem of customs duty on Chinese imports.

    I have checked before posting- with the regional director of a rather large- bloody big!- letters and parcels International firm. His view was not to add problems in old age for such a small benefit.

    I do have a Far Eastern and Indian connection but don't want to run foul of UK regulations

    Thank You

    Norm
     
  17. Oct 22, 2018 #37

    nel2lar

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    [QUOTE="XD351, post: 310056,
    You can pick up some amazing stuff on ebay for the right price if you know what you're looking for and do your homework ![/QUOTE]

    XD
    Since you seem to know what you are talking about what would be a top shelf insert for most cutting? I bought a box of ten and there is a huge learning curve on them. I waste enough money on things I want and can not afford to have boxes of these inserts that just shatter.
    Nelson
     
  18. Oct 22, 2018 #38

    rmd55

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    Unless you are using Sandvick, which has their own mines. The carbide that you get has a very good chance of being Chinese. 80% of the carbide used in the world comes from China and the Chinese have been making high quality product carbide materials since the 1980's. I worked in oil related carbide in the 80's and 90's. We had 3 grades of carbide, cast(never used for machining), 6% cobalt, and 12% cobalt. We also rolled pellets. By 1984 all the cast carbide was imported from China, in-house production was shutdown. By 1990 we had to start to import pellets because the Chinese pellets were better than what we could make. They could use manufacturing that OSHA would not allow here. They rolled the pellets with rubber dissolved in gasoline(petrol). I use a mix of carbide and HSS. I usually break the inserts before they wear out, but I have only been doing machining for a few years and Utube taught. I have some Chinese tooling but also watch for sales and have picked up some Dorian tools when they are ~$2o. The difference I see in the tooling is the finish. The Dorian tools have a better finish also I can get a better description of the tool from Dorian. The Chinese tools give the shank size and the insert size. Dorian give things like rake angle so I can stay away from the highly negative rake tools. That's my 2 cent
     
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  19. Oct 24, 2018 #39

    Wizard69

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    Just got row everybody’s curve, you can get HSS inserts these days. Carbide good or bad isn’t your only choice. HSS inserts for turning are an interesting development but I still think there is huge value in grinding HSS yourself.
     
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  20. Oct 24, 2018 #40

    Ozwes007

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    One other thing you may need to be aware of is the tool holder in all this. Cheap holders are made from inferior materials. I have seen this to many times to discount it. Boring bars are usually the easiest to see this in. You will get from mild to wild harmonics and tip seat distortion in these tool holders. Even had the odd seat area break out. Harmonics of the holder will destroy most tips very quickly.
    To the point of carbide construction, new carbide tips use many exotic materials in there binder to increase individual characteristics of the carbide. On top of that many new tips are designed to be run extremely hot and won’t work properly if not spun fast enough. The coating of the tip is also a major factor in its usage. If your mill or lathe is designed(speed range) for HSS then use HSS, your just going to be disappointed otherwise.
     
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