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Tool Grinder / Wheels for Bench Grinder?

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  • Tool Grinder / Wheels for Bench Grinder?

    I'll be the first to admit that I'll probably still use carbide more often since I frequently play with rusted, welded up chunks of mystery steel that don't necessarily require perfect finish or tolerance, but I would like to spend a little more time working with hand ground HSS when time and conditions permit. A few years ago when I picked up my first old tired South Bend 9 all I had to work with was a few odd pieces of HSS. For those I did what I could for an edge with an ancient 6" bench grinder but when I bought my 12x40 import it came with several cut down 1" tools and well over 100 inserts, so I haven't really ventured back to HSS in a while.

    My old bench grinder has a motor that is bigger than the wheels, so when I have to grind any odd long items it doesn't work well. The motor also pops the GFCIs frequently, so I think I'm going to look for something new and I figured while I was at it I would make sure that I was set up to grind HSS better. All my previous (poor) grinding was done with a 6" round wheel and occasionally the side of the wheel, even though I've been told that it's a no-no. I've seen pictures of the tool grinders like the Baldor and the less expensive Grizzly and out of production Harbor Freight one, but I'm thinking that even the $350 Grizzly is more than I'm willing to spend right now since what I do is mainly hobby level. I'm generally more willing to spend labor in lieu of cash on a project like this.

    I assume tool grinding works better with the cup style wheels on those tool grinders so you are grinding flat and not on the radius, so I was thinking I could convert one end of a bench grinder to use this style wheel and build a better table / rest. I've never seen one of those wheels other than in pictures, but it looks like a round abrasive ring on a metal backer, so I assume I can just make an adapter plate? Does this sound feasible or is there something I'm missing?

    Also, when it comes to the actual wheel what do I want? My most basic understanding is that silicon carbide (green) and diamond wheels are generally for carbide, so for HSS should I just go with aluminum oxide or do I want to head in another direction? Does anyone have a suggestion on a supplier? My experience with abrasives is that the lifespan of name brand expensive ones are often better than budget ones. has anyone had good luck with lesser cost products? And finally, would I want to go with a fine grit wheel for this?

    Thanks,
    Mark
    Last edited by lost_cause; 11-30-2014, 12:23 PM.

  • #2
    I only buy Harbor Fr8, when I can't find the item elsewhere.

    I bought their 3/4 hp bench~grinder-buffer for this very reason.
    8" wheel (which was junk by the way) and a salamander motor housing
    that might be 5 1/2" on a good day.

    Put good wheels on it, I'm a happy Guy.
    I can grind just about anything now.



    Wheels , name brand like Norton, go soft and not too fine a grit.

    Get a good 1inch X 1inch dressing stick while yer at it.
    It'll work on gay metric wheels too.
    Last edited by Old Hat; 11-30-2014, 01:33 PM.

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    • #3
      lost: I wouldn't recommend that you put cup wheels on a pedestal grinder, not really meant for that. Cup wheels are for grinding cutters on a cutter grinder. Get yourself a decent pedestal grinder and put good quality wheels on, like Old Hat said. Can your present grinder accommodate 7" wheels? Cheap wheels are a poor investment . Tool rests, properly adjusted, are important on your grinder. Good luck.

      Sarge

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      • #4
        I'm very happy with the 6in white Norton wheel from sharpening supplies. Puts a much smoother edge on the bit than the ancient old grey wheels it came with.

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        • #5
          A question for those using conventional grinder wheels: are you grinding tool bits on the edge of the wheel? All the close up pictures I've seen appear to show a perfectly flat grind but wouldn't you see a bit of a hollow grind when using the edge of a round wheel? Is this a non-issue?

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          • #6
            You develope a surface contour as desired by a rolling motion
            of the tool-bit.
            If flat is desired, you ease from the base of the tool-bit to the cutting edge
            for heavyer removal. (some go opposite) and it works fine for them.
            And from the edge to the bottom for refinement.

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            • #7
              Lost,

              The radius in the hollow grind that you get won't be an issue as far as strength of the cutting edge on tool bits unless you have a really worn out wheel. I've ground many hss tool bits on a standard pedestal grinder with a 6" wheel. No need to over complicate things.

              Brian
              OPEN EYES, OPEN EARS, OPEN MIND

              THINK HARDER

              BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

              MY NAME IS BRIAN AND I AM A TOOLOHOLIC

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              • #8
                Originally posted by bborr01 View Post
                Lost,

                The radius in the hollow grind that you get won't be an issue as far as strength of the cutting edge on tool bits unless you have a really worn out wheel. I've ground many hss tool bits on a standard pedestal grinder with a 6" wheel. No need to over complicate things.

                Brian
                A hollow releif lacks the full abillity to cary away the heat developed in the cut.
                It also means your edge will brake down faster.
                Better to learn to grind as needed, to extremes if needed.
                Or good-enuff when not needed, and anywhere in between.

                Comment


                • #9
                  You're the expert.

                  Brian

                  Originally posted by Old Hat View Post
                  A hollow releif lacks the full abillity to cary away the heat developed in the cut.
                  It also means your edge will brake down faster.
                  Better to learn to grind as needed, to extremes if needed.
                  Or good-enuff when not needed, and anywhere in between.
                  OPEN EYES, OPEN EARS, OPEN MIND

                  THINK HARDER

                  BETTER TO HAVE TOOLS YOU DON'T NEED THAN TO NEED TOOLS YOU DON'T HAVE

                  MY NAME IS BRIAN AND I AM A TOOLOHOLIC

                  Comment


                  • #10
                    The widest assortment of "good" grinding wheels come with a 1-1/4" center holes. These are meant for tool and cutter grinders and surface grinders. Reducing bushings are available to bush these wheels down to common arbor sizes like 1/2", 5/8" and 3/4". Large washers that more than span the 1-1/4" hole are needed on both sides.

                    A general rule when grinding hard material like HSS is to use soft wheels, they grind faster and cooler. Check some of the abrasive manufacturer's sites to understand recommended type wheels. Be ready for sticker shock, good wheels are not cheap.

                    Cup wheels....yeah, I've used them on a bench grinder. You have to only grind on the narrow flat face though. And, no hard pressure hogging into the wheel, by nature they're more fragile than a regular wheel. Rig up a wheel guard covering the whole wheel in case of wheel fracture.

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                    • #11
                      Here's a thought

                      The H7762 appears to be the same as a unit several here purchased
                      when it used to be available from Harbor Freight. The HF came with
                      silicon carbide wheels that needed to be changed for use on HSS.
                      It also benefitted from post-purchase massaging by owners, well
                      documented in text and videos. Despite being a bit of a project,
                      the HF unit was a good value at the HF price, esp w/ coupon deals.
                      Maybe the more expensive Grizzly unit has addressed some of the
                      rough edges of the HF version.

                      Another thought is to look for either a #500 Baldor 6" Tool Grinder
                      or a #510 Baldor 6" Carbide Grinder. The Rockwell #23-501 Tool
                      Grinder is another machine to shop for. Any of these, esp on an OEM
                      pedestal will probably sell for more than the Grizzly, but occasionally
                      good deals are reported.

                      .

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                      • #12
                        Oops. On rereading p#01 I see the OP has considered
                        and ruled out the Grizzly and domestic machines.

                        .

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                        • #13
                          http://maine.craigslist.org/tls/4703728039.html talk the seller down some

                          there is a similar Milwaukee "near by" in new hampshire for $100 in poorer shape it looks like, still...

                          Comment


                          • #14
                            Originally posted by lost_cause View Post
                            A question for those using conventional grinder wheels: are you grinding tool bits on the edge of the wheel? All the close up pictures I've seen appear to show a perfectly flat grind but wouldn't you see a bit of a hollow grind when using the edge of a round wheel? Is this a non-issue?
                            I know there are some that will advise against this, but I have a cheapy 1" wide belt grinder that I find faster for roughing in a hss blank, then a final touch up on a bench grinder, or maybe just a few licks with a diamond hone.
                            James

                            Comment


                            • #15
                              Originally posted by lost_cause View Post
                              A question for those using conventional grinder wheels: are you grinding tool bits on the edge of the wheel? All the close up pictures I've seen appear to show a perfectly flat grind but wouldn't you see a bit of a hollow grind when using the edge of a round wheel? Is this a non-issue?
                              A little hint. Done right the "hollow grind" as you call it will provide the proper relief you need.
                              Mike
                              Central Ohio, USA

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