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A question about grinding lathe cutting tools on a belt sander

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  • A question about grinding lathe cutting tools on a belt sander

    Hi,

    I want to get a belt/disc sander for grinding lathe tools, but I am unsure how certain cuts are made (or even if they can be made) with them.

    Take this boring bar for example:



    I have made such cutouts (bottom edge of tool in photo) with the edge of a bench grinder, but can the same be done with the edge of a belt?

    Cheers

  • #2
    You'd better stick with your grinder. Bob.

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    • #3
      It seems you have a shltty grinder and you don't know how to make it run well.

      -D
      DZER

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      • #4
        Bob, what about cutting the rake on a standard lathe tool? Is that OK with a belt sander?

        I really don't like using a bench grinder. I would prefer to use it as little as possible. I figure if rake angles can be cut on a belt, then I could do bulk material removal on the bench grinder for something like the boring bar above, then finish up the cutting edges on the belt.
        Last edited by Swarfer; 11-10-2016, 07:44 PM.

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        • #5
          Originally posted by Doozer View Post
          It seems you have a shltty grinder and you don't know how to make it run well.
          You must be some kind of amazing psychic, seeing as that isn't an image of any tool I've made. It was just a clear example of a particular type of cut I found in google images.

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          • #6
            I do the heavy work of shaping a square cutting tool into the proper form on my bench grinder. then I touch it up whenever it needs on my belt sander. A belt sander would be a bit light duty for the initial shaping.
            Brian Rupnow
            Design engineer
            Barrie, Ontario, Canada

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            • #7
              Hi brian,

              How many watts/hp is your belt sander? And what kind of stock dimensions do you grind on it?

              Also, what is it like working at the edge of the belt, with the tool held on the non-abrasive side of the cutting plane - for things like rake angles, or grooving and threading bars? (hope that made sense...)

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              • #8
                I always found belts "spongy" and so the cutting edge would end up slightly rounded. Nothing a minute with an oilstone can't fix though.

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                • #9
                  Hi Andre,

                  Do you know what kind of platen materials were used in the sanders? Or is this a problem even with ceramic glass platens that knife-makers use?

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                  • #10
                    Originally posted by Swarfer View Post
                    Hi Andre,

                    Do you know what kind of platen materials were used in the sanders? Or is this a problem even with ceramic glass platens that knife-makers use?
                    is what a problem - rounding edges or platens wearing out? There's an account on PM of regular old mild steel lasting a very long time as a platen. I'd grab a piece of AR400 but then i've lots of chucks of it around.

                    As to your question, I'm challenged to see making delicate shaped tools on a sander and near impossible for an undercut one like that. I do use sanders for sharpening - 2 1/2" drills for example. For big wide tools they are bloody handy....but think it would be an inferior approach to a bench grinder for lathe tools.

                    At home, I used to have a belt sander but the foot print was too big, sold it. Thinking of making a mini one, bench top version, as they are handy for some things
                    Last edited by Mcgyver; 11-10-2016, 09:15 PM.
                    in Toronto Ontario - where are you?

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                    • #11
                      You can use the edge of the belt. It will wear, but that takes a long time.

                      I have a small, cheap Delta 3 wheel sander with a 1 inch belt that I tend to use a lot. Over the last 20 years I've had only one sanding belt break. I don't think Delta is selling them anymore, but HF has one that is similar.

                      The 1 inch belt in that format is real easy to use, even for undercuts.



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

                      Location: SF East Bay.

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                      • #12
                        Sorry Mcgyver - I meant the rounding edges. I have a local source for Robax ceramic glass that will cut to size for me. Strangely enough, it is easier for me to get than small bits of metals...

                        Can you shed a bit more light on the problems you foresee with delicate tools? Presuming undercuts are first performed on a bench grinder.

                        I have a (slightly irrational) fear of bench grinders. I don't like them. I am very uncomfortable using them. I would rather have a belt fail than a wheel. I also want to be able to cut without a curved face

                        Cheers

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                        • #13
                          Originally posted by danlb View Post
                          You can use the edge of the belt. It will wear, but that takes a long time.

                          I have a small, cheap Delta 3 wheel sander with a 1 inch belt that I tend to use a lot. Over the last 20 years I've had only one sanding belt break. I don't think Delta is selling them anymore, but HF has one that is similar.

                          The 1 inch belt in that format is real easy to use, even for undercuts.
                          Thanks dan

                          How many watts/hp is your machine?

                          Comment


                          • #14
                            I can o a better job with the grinder---

                            Originally posted by danlb View Post
                            You can use the edge of the belt. It will wear, but that takes a long time.

                            I have a small, cheap Delta 3 wheel sander with a 1 inch belt that I tend to use a lot. Over the last 20 years I've had only one sanding belt break. I don't think Delta is selling them anymore, but HF has one that is similar.

                            The 1 inch belt in that format is real easy to use, even for undercuts.



                            Dan
                            I usually simply use my bench grinder, and perhaps a touch with a stone to sharpen my lathe tools, However, once in a while, especially if I am sharpening a larger tool and want a straight relatively long edge I will use the belt sander,and I find it a handy way to sharpen larger drill bits ( Say 3/4" upwards) My tired arthritic hands seem to better manage the drill bits on the sander rather than on grinding wheels. My sander has a 1" by 42 belt and a heavy angle iron platen. hope this helps Regards David Powell.

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                            • #15
                              I agree on the rounding of the edges, it's not ideal.

                              That said, I have made a bunch of tools with my dumb little "Harry Homeshop" Delta made-in-china 30" x 1" belt & 5" disc sander (maybe it is a 6" disc, don't recall).

                              Free-handed a gear cutter once, that I used on the shaper to cut some bevel gears. Used the edge of the belt, and kept trying it up against one of the last good teeth on the old zamak gear until it fit OK on both sides. I forget what I did about the runded edge. Maybe ran the belt AWAY FROM the edge. You can do a lot of things with belt sanders, but in general, I'd far prefer to use a grinder for most cutters.

                              BTW, you can cut that back cutout in the picture OK, if it is wider than the belt. If not, it's a lot more trouble than using a regular grinder.
                              CNC machines only go through the motions

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