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Surface grinder troubles - won't grind the chuck flat

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  • #16
    My 1920's Norton grinder is worn and does lift around 0.005 at the very end of the table travel I wonder if you have a similar problem?

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    • #17
      Originally posted by George Bulliss;817302[QUOTE
      ]I also use large cross feed steps. Can’t remember if it was beaten in my head by a toolmaker while an apprentice or picked up with time.
      Wrong. Take less feed if you want to change your routine

      I think the reason for doing so is that a larger step over will use more of the wheel and spread the build-up over a larger area. A small step means only the leading edge is doing any cutting and the build-up will be concentrated in a smaller area, causing more problems.
      "Build up"? What is that? Nothing is building up, the wheel is wearing. You want the wear confined to a narrow area so that unworn wheel cuts on the next pass. If you feed half the wheel width then by the time you are halfway across the chuck, the whole wheel is worn. Feed .100 per pass and a 1/2 inch wheel is cutting to size 5 times longer. Sure the edge has worn more, but the last .100 is near new and cutting to size.

      When grinding the chuck on a dry grinder, I’ve used both WD-40 and Crisco on the chuck, with Crisco being the winner in my opinion. I’ve also used a cold gun (cold air blast) and that helps a bit too. It doesn’t take much to make the chuck worse than what you started with. Keep at it, keep the cuts as light as you can, and keep the wheel dressed and when you dress, dress it deep.
      [/QUOTE]
      The cold air gun is too localized to help with accuracy in my opinion. The WD40 makes a good cut but carries away little heat. Try soluble oil in a spray bottle. You can keep the chuck quite wet with practice. I do suspect wear due to poor grinding practices such as failure to use the entire surface, even if a little at a time. It could be a oneshot oiler. Try a thinner oil.
      How are you indicating it? If the indicator is mounted on the spindle then it should read "0" everywhere no matter how bad the machine is. You are indicating from the same features you ground from. The real proof is in the pudding. Gring a piece that is fairly large for the chuck and check flatness. If it's good then your indication is at fault. Checking the chuck from the spindle that ground it will never tell you anything. When you check flatness be sure that that is what you check. The part must be resting 3 points the same height and check the side on the points. You cannot check flatness by placing a part on the plate and indicating the top side.

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      • #18
        tdmidget, heat is building up.
        Amount of experience is in direct proportion to the value of broken equipment.

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        • #19
          Originally posted by tdmidget View Post
          The cold air gun is too localized to help with accuracy in my opinion. The WD40 makes a good cut but carries away little heat. Try soluble oil in a spray bottle. You can keep the chuck quite wet with practice. I do suspect wear due to poor grinding practices such as failure to use the entire surface, even if a little at a time. It could be a oneshot oiler. Try a thinner oil.
          How are you indicating it? If the indicator is mounted on the spindle then it should read "0" everywhere no matter how bad the machine is. You are indicating from the same features you ground from. The real proof is in the pudding. Gring a piece that is fairly large for the chuck and check flatness. If it's good then your indication is at fault. Checking the chuck from the spindle that ground it will never tell you anything. When you check flatness be sure that that is what you check. The part must be resting 3 points the same height and check the side on the points. You cannot check flatness by placing a part on the plate and indicating the top side.
          TD,

          You have not spent much time grinding have you?

          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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          • #20
            By build-up, I meant the wheel loading up or clogging with the soft material of the chuck and agree with Jaakko that spreading the clogged area out across a larger area of the wheel helps. Not saying this is the only way to do it, but it's the way I did it.

            I think just about everyone struggles with grinding in a chuck for the first few times and results like yours are not uncommon. I'm sure you do have wear and perhaps some other things going on with your grinder, but I wouldn't use the results of your grinding as an indication of anything other than your grinding.
            George
            Traverse City, MI

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            • #21
              Just about 5 years of 10-12 hours per day if you include surface (Includes Blanchard), jig, centerless, and cylindrical.

              Tell us about your vast experience.

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              • #22
                In reading the post, I have to ask, is the mag chuck on or off when you are doing your readings ?
                Should be off IMHO

                Also, is the dial indicator at the exact point where the wheel touches the mag surface?
                Sometimes, if not at the point of contact, you can see some wierd readings.

                The above does not answer your question on the problem, but may help decipher the cause.

                Rich
                Green Bay, WI

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                • #23
                  Originally posted by Rich Carlstedt View Post
                  In reading the post, I have to ask, is the mag chuck on or off when you are doing your readings ?
                  Should be off IMHO
                  that is good point and suggests another test. Using an anti-magnetic indicator, map the chuck on and off and compare....might give a hint as to whether poor contact between table and mag chuck is in part to blame.

                  One thing I'm curious about is the technique for indicating the chuck - The chuck pulls the tip of the indicator which I presume isn't a problem generally speaking, but I wonder if means depending on the strength of the magnet I'm getting different readings? I need to verify the indicator arm rigidity I think.
                  as Rich suggests, test with chuck off...better yet get an anti magnetic indicator. Did you try as i suggested indicating the table and checking the fit between table and chuck? I still think heat is an issue, can't see wd40 doing that much....but you're in debugging process so tests that eliminate things are a good start.

                  My 1920's Norton grinder is worn and does lift around 0.005 at the very end of the table travel I wonder if you have a similar problem?
                  maybe last night was just too late a night...but wouldn't grinding in situ remove error like this? wouldn't wear result in a non-flat surface being ground on the chuck? Said non flat surface could indicate zero from a point close to the wheel that ground the irregular surface. I can see ways worn to a curve, skimming the chuck grinds that curve into the chuck - its a curved surface but indicators zero. I suppose then to know if things are good you need to both indicate the chuck and check it for flatness a- indicating zero and flatness are not the same thing when the indicator readings are based on the ways it rode in the first place
                  Last edited by Mcgyver; 12-22-2012, 11:50 AM.
                  .

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                  • #24
                    Originally posted by tdmidget View Post
                    Just about 5 years of 10-12 hours per day if you include surface (Includes Blanchard), jig, centerless, and cylindrical.

                    Tell us about your vast experience.
                    And? I know a 60 year old guy who has machined all his life and still can't use a lathe properly, eventhough he was the lathe operator for his career!
                    Amount of experience is in direct proportion to the value of broken equipment.

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                    • #25
                      Originally posted by Jaakko Fagerlund View Post
                      And? I know a 60 year old guy who has machined all his life and still can't use a lathe properly, eventhough he was the lathe operator for his career!
                      i'm with you, not direct at TD, but in general this 'listen to me because I've being doing it for so many years' leaves me cold. There are plenty of hacks making chips for a living, the commercial guys i know complain about them all the time.....while a poster might be the greatest chip maker ever, its the internet; our only way of judging that is how sound the logic and explanation is as to the why. Explain the rational/engineering behind it, full stop. Highly credible guys like Forrest and John S imo are credible because the do exactly that and pretty much only that.
                      .

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                      • #26
                        This my two cents. When ever I have to grind anything on a surface grinder and I want it as flat as the machine can be I always use magnetic parallels and grind them in place. The part to be ground is then placed on top of the parallels with out turning the magnet off. Grinding bearing spacers in this way I was always able to get them within zero to .00005" in terms of parallelism of the ends.
                        Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

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                        • #27
                          Originally posted by Jaakko Fagerlund View Post
                          And? I know a 60 year old guy who has machined all his life and still can't use a lathe properly, eventhough he was the lathe operator for his career!
                          Looking in the mirror? Still waiting on your vast grinding experience.

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                          • #28
                            Originally posted by tdmidget View Post
                            Looking in the mirror? Still waiting on your vast grinding experience.
                            Sorry but no, I'm only 30. My experience has nothing to do with this and as said, it doesn't prove anything, as anyone can claim whatever they want about anything. It is just if your text seems credible and if your claims/ideas/experience has some explanations behind them as to the why's 'n but's.
                            Amount of experience is in direct proportion to the value of broken equipment.

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                            • #29
                              Actually, I think Tdmidget's advice and explanations here are quite sound. The form could've been better, but the substance is OK.
                              Mike
                              WI/IL border, USA

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                              • #30
                                Originally posted by bborr01 View Post
                                TD,

                                You have not spent much time grinding have you?

                                Brian
                                what exactly from the paragraph you quoted did you find fault with? TD's comments on indications are the same as what I posted about - ie zero reading does not mean flat....why do you think this is wrong?
                                .

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