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Newbie indexed carbide questions

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  • #31
    Bented, We are talking about coolant in the home shop
    and you post a link to a brand new 7 axis Robodrill??
    I have rebuilt many machine tools. That's what I do in my shop.
    Coolant absolutely does eff up machines. It takes a while
    but guaranteed to happen. If the machine lasts 10 years
    it is a write off and buy another $100,000+ machine.
    I say again, this is home shop machinist.
    You've got tunnel vision and you are only seeing
    your own slice of the world. I work in a factory.
    I know all our machines use coolant.
    I also see the maintenance department replacing
    spindle bearings and linear guide bearings all the time
    because of coolant ingress. It is a full time job for 3
    men in a 100 person plant. Coolant is an evil posion
    for machines. But it helps make money with fast
    speeds and feeds. Downside is high maintenance
    costs and throw away machines after 7 to 10 years.

    ---Doozer
    Last edited by Doozer; 07-13-2021, 08:36 PM.
    DZER

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    • #32
      Doozer, my BP clone mill came with a flood coolant option and I've never used it for exactly the reason you cited which I learned from this very site before I bought the mill over 30 years ago.
      Last edited by Arcane; 07-14-2021, 06:00 AM.
      Location: Saskatoon, Saskatchewan, Canada

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      • #33
        Originally posted by The Metal Butcher View Post

        Agree. We've got half the forum telling him to use HSS, and others saying coolant is a nessesity? What a conflicting opinion. Lord help the newbies with this level of advice.
        It's OK - I'm used to the concept of people on the internet disagreeing with each other! Also, because this for home shop machining I don't need the right answer to make everything work perfectly straight away, but ideas for things to try and experiment with as I learn. I've got lots of interesting ideas from this thread on different inserts to try, what to do with speeds/feeds on light cuts, and how to grind my HSS better, and I'll be experimenting with all of these. I'll leave the flood cooling though - regardless of the rights/wrongs it looks like way too much hassle and mess.

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        • #34
          hollo I must agree with Nickel. I was in another thread about the same subject with similar problems you have. Nickel recommended the aluminum inserts for most materials, (more rake, hook angle and sharpness)
          so I tried them. It was night and day considering my lathe is a small wimpy south bend 9 inch. I changed most of my inserts to these polished gems.

          They are a bit fragile though, so be careful with interrupted cuts if you can. Spin the work as fast as you can yet to keep chips from launching across the room. You'll get a beautiful surface finish with less heat buildup in the part. These require a lot less tool pressure which my machine appreciates.

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          • #35
            I will add....
            I have a large upright drill press.
            A Cleerman. 4 Morse taper. 8 foot tall.
            12 geared drill speeds, 9 power downfeeds.
            I might use coolant in it
            because drilling with large bits makes LOTS
            of heat, and it is a drill press. No slideways
            to gumm up get rust/rot and have their oil
            lubricant fail from coolant ingress. So in my
            mind, coolant make sense for this machine
            of mine, because there is nothing for the
            coolant to muck up. But even then, I might
            run straight WD40 because it smells nice.

            --Doozer
            DZER

            Comment


            • #36
              Originally posted by Doozer View Post
              Bented, We are talking about coolant in the home shop
              and you post a link to a brand new 7 axis Robodrill??
              I have rebuilt many machine tools. That's what I do in my shop.
              Coolant absolutely does eff up machines. It takes a while
              but guaranteed to happen. If the machine lasts 10 years
              it is a write off and buy another $100,000+ machine.
              I say again, this is home shop machinist.
              You've got tunnel vision and you are only seeing
              your own slice of the world. I work in a factory.
              I know all our machines use coolant.
              I also see the maintenance department replacing
              spindle bearings and linear guide bearings all the time
              because of coolant ingress. It is a full time job for 3
              men in a 100 person plant. Coolant is an evil posion
              for machines. But it helps make money with fast
              speeds and feeds. Downside is high maintenance
              costs and throw away machines after 7 to 10 years.

              ---Doozer
              I suspect that you were completely oblivious to the entire tongue in cheek nature of the post.
              Therein lies the entertainment. Keep up the good work.

              I quote myself here.

              "Virtually any new machine that you buy will come standard with a sump, pump and coolant lines installed, this is a money grab by the manufacturers.
              The Evil Bastards, they have no shame."
              Last edited by Bented; 07-14-2021, 08:13 PM.

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              • #37
                Originally posted by hollo View Post
                I thought I'd experiment with some indexed carbide. I hate grinding HSS bits (grinding wheels scare me - I'm always convinced they're going to explode!). Also I wanted to make some big steel bolts for attaching a small treehouse and it seemed like the right project to try on.
                I've got a holder (cheap Korean import) and some WNMG080408 inserts that fit it, and wasn't expecting much, but it's amazing compared to HSS. 1- 1 1/2" diameter EN3B mild steel. Running at 1500rpm or just under (aiming for c. 400fpm), and then experimenting with feed/depth of cut. 0.04"/revolution and 40-80/1000" depth of cut gave some really nice results with blue chips, no chatter, and (by my standards) a really nice surface finish.

                Where things went less well was when I tried to hit my finish OD. I had about 12/1000 to take off, and doing this at the same settings produced loads of sparks from the tool/workpiece, and both got really hot. Should I have changed speed/feed for this final cut, or can my cheap inserts just not cope with a shallow cut like this? If so how do you get around it? Is it a case of hitting final dimension from a distance or changing tool for the finish cut? Also do all these sparks mean I've ruined the corner on the insert?

                Pics below of the finish I was getting, some nice blue chips, and the insert after I made all the sparks with it.
                A couple of observations;

                Running carbide on mild steel at near 400fpm is pushing the fast side of perfection. I usually start at 300fpm and will go faster if the setup allows.

                You were getting good results on those roughing cuts because carbide relies on pressure to plow the material off, and sufficient speed to let the chips take the heat of cutting with them.

                Those roughing cuts are via brute force. When it comes time for a light measuring cut and a finish pass it would be better to switch to a tool with a razor sharp edge, like those carbide inserts that mimic HSS. To help control heat buildup, and to improve surface finish I will brush on some cutting oil with the finish pass. If I'm still using carbide for the finish I will keep the 3-400fpm speed.

                For a so-called newbie, it sounds like you've got a good grasp of the process.

                Comment


                • #38
                  Originally posted by hollo View Post
                  I thought I'd experiment with some indexed carbide. ​
                  I think you will like them, whatever the shape. As long as they are not too large.

                  I like the two hundred series. They are smaller and work well for me.

                  The 300 serires gets to be a lil "big" for my lathes. So I dont mind grinding them to a sharper point. Then they work much better and the big inserts are less expensive. They last for many turns. JR



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                  • #39
                    Originally posted by BCRider View Post

                    Another option is to find some of the fairly extreme shaped inserts intended for finish cuts in aluminium. Something like THESE. You only want to use them for that last few thou though. For anything heavier the cupped edge is too weak and will break away when used on steel. But a lot of the others here have used this combination of regular for roughing then switched to these inserts intended for aluminium for the last fine passes for size with good results.
                    Where do you find the specifications for those? How do you know if they will fit your holders???

                    p.s. They're only $12 on Aliexpress

                    Comment


                    • #40
                      A ton of info on the Carbide Depot site. As a noob yes it can get very confusing. As a home shop tinkerer and after 20 years of inserts I still get confused.
                      http://www.carbidedepot.com/

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