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  • chipping inserts?

    I bought one of those SCLCR turning tools which takes normal CCMT inserts. So far I've broken both cutting edges on two separate inserts, and I can't figure out why.

    The tool is on center (perhaps a small bit above, actually), and I don't think my feed rates are too excessive. I'm running the lathe as fast as it'll go, which isn't too fast (it's an old Clausing, so around 700rpm), as per the calculator on the LMS site.

    The work piece was a 1" piece of HRS.

    Anyone have any clues? Experimentation will get expensive!

    I tried a brazed carbide tool, which worked better, but the lathe kept bogging down on any cut more than a few thou - I have a feeling someone replaced the motor with a tiny one at some point in the past. I have a bigger motor I'm going to put on it and see if that helps.

  • #2
    You don't want the cutter tip above center. What is the feed your using? How far out from the chuck is the shaft sticking? Are you sure the belt isn't slipping?
    It's only ink and paper

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    • #3
      Originally posted by Carld
      You don't want the cutter tip above center. What is the feed your using? Are you sure the belt isn't slipping?
      Yeah, the belt isn't slipping - the motor just stalls. I think it's way too small.

      I have to machine a bit away from my tool holder to get the cutter below center, but that's no big deal.

      The feed is something like 150tpi? I don't remember exactly, to be honest.

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      • #4
        If it's an interrupted cut, that will chip it pretty fast.

        As Carl said, you want to be right on center, not above. If it's above and grabs then it will be forced deeper into the steel. Is there slop somewhere that is allowing it to dig in deeper than planned? Bearings in the head loose? Gibs loose?

        Even my 7x10 lathe can do .025 into HRS, so yours should be able to also.

        Dan
        At the end of the project, there is a profound difference between spare parts and extra parts.

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        • #5
          Originally posted by danlb
          If it's an interrupted cut, that will chip it pretty fast.

          As Carl said, you want to be right on center, not above. If it's above and grabs then it will be forced deeper into the steel. Is there slop somewhere that is allowing it to dig in deeper than planned? Bearings in the head loose? Gibs loose?

          Even my 7x10 lathe can do .025 into HRS, so yours should be able to also.

          Dan
          You know, I think there might be a tiny bit of play in the headstock bearings - I picked this lathe up during exams and haven't had a lot of time to go over it. I'll put on the new motor, machine that tool holder, and tighten up those headstock bearings, and give it another shot.

          Thanks guys!

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          • #6
            If the tip is above center, there will be pressure below the cutting edge that will fracture the insert, it is a much greater problem with inserts than with solid HSS cutters.
            North Central Arkansas

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            • #7
              If you are facing having the cutter above or below centre can chip the tip real fast

              Terry

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              • #8
                On facing, going past center will chip carbide too, as the work is coming up from the bottom once you pass center. If possible, I will center drill or if it needs a hole, do that first. Then when facing, you go to a void before hitting center.

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                • #9
                  Another thing. Hot rolled steel is a mixture of all kinds of steel bits. You will often find hard spots from ball bearing or end mill shank that didn't completely get melted and homogenized into the mix.
                  Jim (KB4IVH)

                  Only fools abuse their tools.

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                  • #10
                    All Chinese steels are that way. Chinese steels quality sucks.
                    It's only ink and paper

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                    • #11
                      Originally posted by isaac338
                      I bought one of those SCLCR turning tools which takes normal CCMT inserts. So far I've broken both cutting edges on two separate inserts, and I can't figure out why.
                      What inserts are you using? The ones that come with the tools are not great.

                      I have a similar set, by Glanze, and when I changed to a brand name insert it was night and day.

                      Comment


                      • #12
                        Originally posted by Carld
                        All Chinese steels are that way. Chinese steels quality sucks.
                        you know you guys really gota stop picking on the chinese its not their fault if the guy buying from them wants to pay in rice instead of cash if you get the meaning, ok no offence intended and if your going to buy the steel then live with it and stop crabbing about it,

                        i dont care who makes what and if i get junk i just dont by it again , even the USA makes junk and so does canada and germany and everyone else and we all make good stuff as well.

                        it seems on this fourm people always chooes to bash the chinese and thats not right its plain out ignorent and you dont even look at your own junk your countrys produce ..

                        iam canadain and they make standard modern lathes here and to me they are junk and they got some serious issues in my books and i would not even take one if it was free, well ok for free then id take it to the salvage yard and get money for it..

                        my mill and my lathe are chinese and darn good ones and they work slick no complaints,
                        the first lathe i got was also chinese but it was a junk one after 2 months it FRIED on me was not pretty so back it went to princessauto and then i went to busy bee and gota real lathe and mill. my tooling i buy from a local place in town that carries all the good toys for machinests ,

                        you get what you pay for in this business

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                        • #13
                          Not all offshore machines are Chinese as many people think. There are a machines that are made in Taiwan and they tend to be considerably better than the Chinese machines but are a bit more money too. They've been at it for quite a while now and have refined their product somewhat whereas the Chinese are just getting started at this game.


                          Umm...... Busy Bee? I've only ever seen crap machines from there, but that's just my opinion of there quality.

                          al
                          I spent most of my money on women and booze, the rest I just wasted.

                          Comment


                          • #14
                            Originally posted by The Fixer
                            Not all offshore machines are Chinese as many people think. There are a machines that are made in Taiwan and they tend to be considerably better than the Chinese machines but are a bit more money too. They've been at it for quite a while now and have refined their product somewhat whereas the Chinese are just getting started at this game.


                            Umm...... Busy Bee? I've only ever seen crap machines from there, but that's just my opinion of there quality.

                            al
                            well iam going to let you in a a trade secret here, if the guy ordering the machine in says to the china usa ot twian guy ill give you 75.00 per unit and ill take 2000 of them then you get a 75.00 POS different guy goes same factory, says ill give oyu 150.00 per unit and ill take 2000 of them , then you get a nice machine

                            get the math here, by the way that 75.00 machine for to buy it retail is going to cost you about 500 to 700 and then 150.00 ones cost you 1200 to 1500

                            now if you cant fiquire this out then you need to get into the import export business , like a friend of mine is and then you ll learn something ,,

                            how long the chinese vS twian have been at it is not the issue its what the importer is willing to pay that will detereman the quaility you get, as for busy bee machines must have been a 3in1 cause my 10x18 lathe and 7x20 mill blow the crap out of anything house of tools or HF has in compareson in the same size machine same as grizzly the busy bee stuff is better made, and yes i have seen the machines form the other places and was not impressed,even KBC sells what looks in the picture but up close its a POS and its 1250 when its on sale,,lots more goodies with it but the machine is junk and a waste of good money, Grizzle has brought out a mill now that is almost a clone to my 7x20 and in looking it over its less of a machine then mine..

                            YOU GET WHAT YOU PAY FOR AND DEFENTLY GET WHAT THE IMPORTER PAYS FOR GOOD OR BAD , if all the deal is out to make a fast buck then you pay less and pass off junk and make lots of money, if you care about your customers youll pay more get better quailaty still make lots of money and have happy cutomers instead of pissed off ones..

                            its like a machinest if you do a poor job but it works you wont stay in business long, but youll make alot of money ripping people off till they catch on , but if you do a great job youll get more and more and more jobs and makes lots of money and be reccomended to many people..

                            automotive repair same deal .good work do it right the first time get lots of reccomendations make lots more money.do a half ass job get it out of the shop rip the cutomer you go out of business...

                            when you rebuild and sled engine are you going to use stock pistons or aftermarket kimpex junk. think about it , more stuff then you realize is now made in tiwan and china why cause it gets done cheaper but you have different levels of cheap a 5.00 piston and a 20 dollar piston huge dfference, cost price on that to the importer by the way, retail 45.00 vs 100.00 or more

                            this is thing not many people realize this and get yinked alot .,most dont even look clsoely into something before they buy it, whats the consumer report say, whats the price differnces is it better to cheap out buy 500.00 on that new lathe or spend the extra,,

                            HF is the most complained about on this board of any other 2nd is grizzly and 3rd not often seen but some have there issues with busy bee but not to many ill tell ya ,

                            if i see to many bad marks about a product i wont buy it,

                            mastercraft great socket sets can not go wornge at all ,wrenchs and so on all great, now drills sawsalls sanders dremels and the list goes on and on and on all junk crap that should never hav hit the shelfs at all..

                            i can pick on 1000 compmanys and point out good and bad in all their products and not even buy any of them

                            how ever job mate drill press great machine job mate bench grinder great dremels great, so that list ended fast..

                            bottom line i care about where my money goes i work my ass off for my money and i dont like wasiting ..

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                            • #15
                              Well, I put a new 220V 1.5hp motor on the lathe and it'll hog some pretty hefty cuts without even slowing down, and it runs way faster (motors are rated the same speed though) - the old motor was probably just spent. I still need to wait till I get paid to pick up another insert, though.

                              I have a brazed carbide tool that works well, but I'm having trouble getting a decent surface finish. I've tried heavy cuts, light cuts, fast feeds, slow feeds, and even HSS with varying nose radius', and the part always comes out pretty rough. Is it possible to get a super smooth finish with HRS or should I get some leaded steel?

                              edit: and yes, the tool and inserts are inexpensive gear, probably of Chinese origin, from busy bee, but the lathe is a Clausing 12" from 1943...
                              Last edited by isaac338; 02-17-2010, 11:48 PM.

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