Chinese tooling and surface finish.

  1. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    Chinese tool, Chinese Insert, Chinese tool post, Chinese live centre, British lathe.

    There is some crap out there (like the recent batch of dcmt Inserts i received) but a lot of it is such great value and can work excellent.

    Hard to complain when you can achieve finishes like this. Can't wait to get my 3hp motor in and feed even harder.

    IMG_20200426_150842.jpg
     
  2. mtt.tr

    mtt.tr Member

    Messages:
    4,084
    Essex England
    What depth of cut is that? Ive Ive mostly been pleased with the cutter i buy like you say value and cut quality its hard to complain
     
  3. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    .032 (0.8mm) DOC @ 750rpm, about all the puny 1.5hp motor can deal with at the feed rates I was using.
     
  4. Kram

    Kram Member

    Messages:
    1,786
    Location:
    Sussex
    Trick of the light? Your centre looks very off centre.
    Positive inserts might get you a much bigger doc, I can do about 2-3mm in HT steel with a ccmt06 and 1.5kw.

    I wanted to ask what you use for milling in the face mill they all seem really blunt. I did some tests regrinding them, and with the sharp aluminium ones and was much better. Is it just that you take a bigger DOC and I cant? But big HSS endmills are always sharp..
     
  5. mtt.tr

    mtt.tr Member

    Messages:
    4,084
    Essex England
    i use negative rake top of my head name escapes, typically manage 2mm on 1hp although i fell i probably have a bigger motor as it doesnt struggle but ive never checked it
     
  6. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    @Kram

    it's because of the way wiper cover it's throwing the eye, it does look off centre.

    3mm DOC? @ what feed rate? That's a 0.8mm DOC but 1.6mm off the diameter, can usually do about a 2mm DOC depending on material/size etc

    I'm feeding as fast as it will allow me there to get the chips breaking. I have holders for ccmt09t and dcmt11t but really at the rates I was feeding it wouldn't be any different.

    If I did a nice slow feed I could hog off more but you don't get the nice finish.

    I just use the standard cheap inserts from eBay in the face cutter, I tend to take 3-5mm DOC with it on the Elliott, I'm looking forward to seeing how it copes with the big 6 inch facemill I got on here.

    I don't remember showing that on here? Where was that?
     
  7. Kram

    Kram Member

    Messages:
    1,786
    Location:
    Sussex
    Sorry 3mm diameter 1.5doc on mine. I feed by hand but Ive found as fast as I can will break the chips. 300-700 rpm and rigidity is limiting motor could go much further.

    Your thread tooling failure :D Convinced me to get the facemill. Id be interested to see the difference on a big machine. Can send you a couple of inserts to compare if you want?
     
  8. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    The 3hp motor will make a big difference but Id like a vfd before I install it so I don't lose the lower rpm ranges.

    Ah, yeah they endmills aren't as good as the facemill but they are still useful.

    The sharpened ones? I'd be happy to give them a go. If it's the aluminium ones shoot me a link and I'll maybe buy some. Aluminium inserts do work good on steel.
     
  9. Welderpaul

    Welderpaul Moderator Staff Member

    Messages:
    13,602
    Location:
    Yorkshire
    What's peoples thoughts on negative and positive rake lathe tools? There seems to be pros and cons for each type.
     
  10. Brad93

    Brad93 M J B Engineering

    Messages:
    10,397
    Location:
    Essex
    Depends on the power of your lathe and the material you are working with.
     
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  11. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    I tend to stick to positive and neutral rake because of my machine size, but the cnmg negative rake is good for ploughing material off

    But as Brad says it's all machine and material dependant.
     
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  12. Kram

    Kram Member

    Messages:
    1,786
    Location:
    Sussex
  13. Brad93

    Brad93 M J B Engineering

    Messages:
    10,397
    Location:
    Essex
    CNMG and DNMG can take 1.0mm cut so 2mm off diameter on my 1.5hp lathe.
     
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  14. mtt.tr

    mtt.tr Member

    Messages:
    4,084
    Essex England
    Positive rake do not like intermittent cuts tends to break them, I typically use cnmg and HSS as the latter will make clean shallow cuts something carbide wont do well
     
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  15. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    Rule of thumb is not to take a cut shallower than the insert nose radius.

    I tend to finish with Emery. :D
     
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  16. mtt.tr

    mtt.tr Member

    Messages:
    4,084
    Essex England

    If it works, it works
     
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  17. brightspark

    brightspark Member

    Messages:
    31,750
    Location:
    yarm stockton on tees
    I hope u cover the bed up whilst doing so wouldn't fancy buying a lathe of u if u didn't :)
     
  18. grim_d

    grim_d Unlikeable idiot.

    Messages:
    3,103
    Location:
    Scotland - Ayrshire
    I pop a rag down then clean the ways after, I'm pretty sure I like my lathe more than my wife. :laughing:
     
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  19. Welderpaul

    Welderpaul Moderator Staff Member

    Messages:
    13,602
    Location:
    Yorkshire
    Its a 3HP lathe, DNMG inserts, material..mild steel/EN8/stainless typical.
     
  20. Brad93

    Brad93 M J B Engineering

    Messages:
    10,397
    Location:
    Essex
    Positive tooling achieves a better finish and
    mild steel and EN8 a positive insert is going to give a better finish.
     
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