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Sharpening brazed carbide?

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  • Sharpening brazed carbide?

    Can anyone offer some tips on sharpening brazed carbide tools?

    I have a set of those brazed carbide boring head bits; they work nicely but I've managed to chip the cutting edges of a few of them.

    I grind all my own HSS lathe tools, but haven't had much success resharpening these carbide bits. I'm guessing I need a different grinder wheel, but don't know what to get, and any other tips would be appreciated.

  • #2
    I grind them all the time. Use a "green" wheel or silicone-carbide. These are highly friable so wear a mask and eye protection.

    Added: Don't use your green wheel to grind steel. Keep the wheels separate even if you have to buy a new grinder.
    Last edited by CCWKen; 10-29-2014, 02:42 PM. Reason: Addition

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    • #3
      You need a diamond wheel. A standard carbide grinder like the ubiquitous Baldor or one of the imported copies is ideal. if you use a quick change tool post, the standard boring bar holder provides a simple way to hold the bar shank and the table angle can be adjusted to provide the proper clearance angle. It becomes simple and fast to regrind the cutting edge with precision.

      Alternatively, you can freehand grind the edge but you still need a diamond wheel and a suitable tool rest. You also need some secure way to hold the bar( Visegrips?) Don't buy a silicon carbide green wheel. They are cheap and but useless.

      If a diamond wheel is too costly, then just toss the dull boring bars and buy new ones; they are cheap.

      RWO

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      • #4
        LOL...

        Don't buy a diamond wheel. They are expensive and you don't need them. A green wheel works just fine. You can use a cheap diamond hone after that to put a good edge on it. And you don't need a Baldor grinder either. I use a standard bench top grinder. Learn to grind the tooling and you can save money. That's what HSM is all about.

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        • #5
          http://r.ebay.com/qlSrCU

          Doesn't need to be expensive. Gren wheels do the job but nowadays there's much better and it won't fill your workshop with grit.
          Peter - novice home machinist, modern motorcycle enthusiast.

          Denford Viceroy 280 Synchro (11 x 24)
          Herbert 0V adapted to R8 by 'Sir John'.
          Monarch 10EE 1942

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          • #6
            I quit grinding carbide tooling years ago--hardly ever use HSS either. There is so much good insert tooling out there nowadays that I just don't see the point of wasting time grinding tools. Once you acquire a few toolholders the inserts are readily available and there isn't anything they don't do better than HSS or carbide...
            Keith
            __________________________
            Just one project too many--that's what finally got him...

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            • #7
              Im with Ken on this. And I have ALOT of ways to grind carbide, more diamond wheels than you need along with more grinders than needed. But keep it simple. Regular pedestal grinder and a GOOD silicon carbide grinding wheel. There are some worthless ones out there. Usually attached to a harbor freight grinder I happen to like norton but there are many more available.

              I also have 1000s of new inserts with all the various holders and I still grind my brazed carbide tools.

              Like Ken said. This is HSM. Simple works real well.... JR
              Last edited by JRouche; 10-30-2014, 01:25 AM.
              My old yahoo group. Bridgeport Mill Group

              https://groups.yahoo.com/neo/groups/...port_mill/info

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              • #8
                I use a lot of carbide insert and solid carbide tools. I also use a lot of HSS and brazed carbide tools, whichever is (in my opinion) the best tool for the job. I will seldom use a brazed carbide tool as bought without sharpening. I feel the green wheel works fine for most things, while a diamond wheel gives a better quality edge.

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                • #9
                  Such a range of opinions! so here's mine:

                  Get a good quality (Norton) green silicon carbide wheel to fit your grinder. Try it out. Be sure to do something about the dust...use a good dust mask. If it works to your satisfaction, good. If not, then you haven't wasted too awfully much money.

                  Diamond wheels cost a lot more but have their own advantages and disadvantages. In the long run they cost less, but are somewhat more delicate. Damage a diamond wheel and you've lost a good bit more money than if it were a silicon carbide wheel. Diamond requires coolant. On the other hand, diamond will give a better finish, faster.

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                  • #10
                    Get a diamond wheel. Good green wheels are useful, but imo.. diamond is so much better. They do not require coolant for carbide. Green wheels beat the crap out of the carbide and leave a poor edge. Diamond wheels are not unreasonably expensive. For home shop use they last forever. Don't grind steel on them. I've had one for 10 years - never looked back. The "green wheels" found on the typical harbor freight grinder are basically colored concrete, and junk.

                    No matter what you use, wear a mask and do it outside. Carbide dust is dangerous and a mask isn't suficient (but wear one!)- you also need to keep it out of the shop or anywhere where stirring it up will result in you or anyone else breathing it.
                    Last edited by lakeside53; 10-29-2014, 10:09 PM.

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                    • #11
                      The diamond engraving wheels sold on Ebay work super for grinding carbide and they cost $7.00 each. Member VetteBob bought a set from 260 to 1200 for under $60.00. He put on the side of his slow Grizzly wood chisel sharpener he bought for under $100.00. I have also seen where a student glued one of these engraving wheels to a aluminum plate with arbor he ade and put it in his engine lathe and ran a slow speed. Times have changed and you can buy Cheap diamonds and trow away those green wheels.
                      this is a single wheel, but I didn't search ebay for long. But his is the type and cheap price. I use a Glendo grinder that has a slow 300 RPM and the carbide does not get hot. I rough with a 260 grit and finish with a 600...get a super lapped finish with a 1200. http://www.ebay.com/itm/Diamond-Coat...item2c83f737b6 Riich
                      Last edited by Richard King; 10-29-2014, 09:55 PM.

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                      • #12
                        Using an 80grit green SC wheel on carbide is like using 30grit alox on HSS, it works but even a little magnification shows a terrible cutting edge. You don't need much diamond area
                        to cut carbide and the UK ebay listing shows good examples of inexpensive very usable diamond wheels. Ideally you would have a 200-400 grit for cleaning up major chips and
                        a 600-1200 for the cutting edge.

                        Agree with lakeside on this, and on his description of the HF 'SC wheels as colored concrete'. Even the plate is green.
                        Steve

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                        • #13
                          In S Africa we dont have E bay.I would like to get a diamond wheel. I got a price from a local supplier and it quoted $150. Would it not be possible to load some diamond paste on an old brake disc and get similar results. Or does it need to be a cup wheel. Could one not load paste on a piece of machined cast iron and then one could have a edge and side all in one wheel. Do normal bench grinders go too fast for a diamond wheel?

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                          • #14
                            Originally posted by plunger View Post
                            In S Africa we dont have E bay.I would like to get a diamond wheel. I got a price from a local supplier and it quoted $150. Would it not be possible to load some diamond paste on an old brake disc and get similar results. Or does it need to be a cup wheel. Could one not load paste on a piece of machined cast iron and then one could have a edge and side all in one wheel. Do normal bench grinders go too fast for a diamond wheel?
                            You would in effect have a lapping plate.
                            Ideal for the last stage of sharpening but not for grinding.

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                            • #15
                              I googled Ebay south africa == http://pages.ebay.co.za/

                              also clicked on one of the several links on that page and found this


                              http://www.tootoo.com/s-ps/diamond-e...p-4614391.html

                              I have been grinding carbide for over 45 years. When diamond wheels were expensive I used green wheels, Now when you can buy them for less then a green wheel your being stubborn and IMHO dumb not trying them. I haven't owned a green wheel in 20 yrs. Also by the time you make an aluminum plate, buy the diamond paste you could have bought a handfull of different sized diamond engraving wheels.

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