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  • When you say "wet" do you specifically mean water? I have got an MQL mister now but so far have only been using it for air to clear the chips - works nicely for flycutting. I could load it with some (diluted) Tufcut Aqua that I have from when it was possible to buy the tiny bottles of the stuff. Or I could put water in it...or use a spray bottle as I was using when hand lapping. It's just a bit difficult to hand crank smoothly and spray with the other hand.

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    • Yes, actual water, probably with a tiny bit of detergent in it to break the water tension and allow it to "wet" the surfaces.

      I have a Glendo accufinish, with a slow speed wheel on a horizontal axis, that grinds on the side. I give it a spray of water before I start, and it lasts until I am done. That is essentially a honing machine, so I do not need continuous drip
      2730

      Keep eye on ball.
      Hashim Khan

      Everything not impossible is compulsory

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      • Originally posted by Cenedd View Post
        Finally something that fits the category! I saw a Joe Pieczynski video a while back on diamond grinding HSS on a mill. Obviously that went in my shopping basket and obviously I've done nothing with it for the last 18 months. Now, I've bought myself a nice set of 8 chisels for a project and standards aren't what they were in the 70's (when the other two 'identical' chisels I've got were made) and the backs need a LOT of flattening. It's still taking too long even on a 120 micron diamond plate (that's approx 140 grit). I know there are shortcuts involving a tiny back bevel but partly I want these as perfect as I can get them - they have sort of inherited sentimental value as they replace the missing ones out of my dad's set - and partly the back is so bad that one entire corner is unusable as is. Clearly the overkill solution would be a surface grinder....and I did look! There was even one of the mythical bench size variety available...but collection only from three hours drive away....and it's been very difficult to get fuel here in the UK for the last week of so. It would have needed work anyway as it looked like it was someone's self-build project. So I suddenly remembered I had this resin-bonded diamond wheel that just needed an arbor. One chunk of EN8 (roughly 1040 equivalent) later and here we go. Turned the shank first and then held that in the 20mm collet that it'll be running in to do the other side.



        Runout was....far from what I'd hoped it'd be. I'm not sure how much was my failure and how much was in the wheel but it clocked in at 0.3mm on the outside of the cone and the edge of the flat at the bottom. So I just chucked the whole lot back up in the lathe and trued it inside and out - the arbor's dedicated to this tool anyway so it won't be coming back off.




        There shall be some unimportant test piece tried first, of course....and much covering of things shall be done first
        What grit is it? Well, I guess we're going to find out as it's unspecified. Could be about 200-ish as other "D12A2" wheels seem to be. Gotta give these things a try.....even if it's just to find out that they don't work!
        Why are you using a diamond wheel on steel. I spent the last 10 years of my career grinding all sorts of stuff but diamond wheels only got used for carbide and occasionally M4 tool steel. With coolant you may not ruin the diamond wheel but an aluminum oxide wheel will do just as good of a job.
        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


        • Originally posted by bborr01 View Post
          Why are you using a diamond wheel on steel.
          Ah, that's an easy one. I'm using a diamond wheel.... because a diamond wheel is what I have.

          Originally posted by bborr01 View Post
          With coolant you may not ruin the diamond wheel
          I'm not aware of any sources saying this would be an issue. With excessive heat diamond theoretically dissolves in steel but not in the range of heat I'm likely to encounter unless I make a right hash of it....which is entirely possible It's a resin-bonded job not an electro-plated nickel solid wheel so it's intended to be friable/consumable to a certain extent....but you have to use it to do that rather than keep it in a drawer gathering dust.

          Originally posted by bborr01 View Post
          but an aluminum oxide wheel will do just as good of a job.
          I don't doubt that you're right...but I don't have one of those other than on a bench grinder and I have form at being terrible with one of those. I need something more finely controllable or I'll just make it worse. I'm not saying it isn't possible to do on a bench grinder; just that I'm fully aware of my skill-limitation. Frankly, if it comes to it, the learning curve is more valuable than the cost of the wheel.


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          • Yes, water cooling helps with diamond tooling. I have tried using diamond on HSS without cooling, and it died - although that might have been general destruction rather than diamond dissolving. Early days.

            I even water-cool AlOx when grinding cryo-steel, not to mention diamond grinding on basalt (Mohr 9).
            Click image for larger version

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            • Thanks Roger, I'm only trying to take a relatively small amount off rather than the sort of deep carving it looks like you're doing but I'll try to get as much coolant on it as I can. I'm not in any way set up for flood but I'll get mist on it and break out the hand spray. I'll post back some results when I can - whether successful or a dismal failure.

              Comment


              • Originally posted by Cenedd View Post

                Ah, that's an easy one. I'm using a diamond wheel.... because a diamond wheel is what I have.



                I'm not aware of any sources saying this would be an issue. With excessive heat diamond theoretically dissolves in steel but not in the range of heat I'm likely to encounter unless I make a right hash of it....which is entirely possible It's a resin-bonded job not an electro-plated nickel solid wheel so it's intended to be friable/consumable to a certain extent....but you have to use it to do that rather than keep it in a drawer gathering dust.



                I don't doubt that you're right...but I don't have one of those other than on a bench grinder and I have form at being terrible with one of those. I need something more finely controllable or I'll just make it worse. I'm not saying it isn't possible to do on a bench grinder; just that I'm fully aware of my skill-limitation. Frankly, if it comes to it, the learning curve is more valuable than the cost of the wheel.

                If you're willing to sacrifice the diamond wheel then grind away. I worked in a cutter grind department for a time and we had carbide form tools that were silver soldered to mild steel with dovetails on them and we always relieved the carbide by grinding the steel away with a aluminum oxide wheel in a surface grinder using flood coolant. If it wasn't needed to preserve the diamond wheel we wouldn't have taken the extra step.

                Also, aluminum oxide wheels are available in most any size and shape that a diamond wheel is available in so you don't need to do it on a bench grinder to use aluminum oxide.

                One last thing. The grinding grit is death to things like ways and gears so I'd be covering up the rack and pinion gears that are shown in the picture and use a vacuum to reduce the amount of grit flying around. I think the guy was named Forrest that used to routinely lecture about that on this site.

                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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                • I did a quick bit of searching earlier and it seems this is all previously-trodden ground and on this very forum too. This is the thread from 2011 covering it.

                  I definitely plan to cover things to protect from grit - just as I do when using emery paper on the lathe. I did make a vacuum nozzle with pins to fit a knock-off Noga arm on a mag base so I'll see if I can adapt that to my new extractor (one of the reasons I'm keen not to go spending extra money on any more tooling at the moment!).

                  Comment


                  • Originally posted by bborr01 View Post
                    ... If it wasn't needed to preserve the diamond wheel we wouldn't have taken the extra step. ...
                    Ehhh ... maybe, maybe not. They/you could have experienced diamond wheel destruction in some situation and decided not to ever use it on steel. Not knowing any particulars, of course, I doubt that any controlled study was done (that diverts manpower). Not using it on steel was _sufficient_ to prevent loss, if not _necessary_. People do tend to conclude "necessary" when all they have seen is "sufficient".

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                    • https://www.practicalmachinist.com/v...-blade-326313/

                      Cheers
                      Roger

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                      • Ok, results
                        This was my setup. The angle between the 'top' face of the chisel and the back was a little more than 1.75° but not as much as 2°. So I went with slightly shy and jacked up the end to fine adjust. I worked out the sfm's of the Tormek diamond wheel and also Evan's wheel in the 2011 thread I linked to earlier. That gave me 260sfm and 630sfm so I had some guides to work within at least. That equates to 250rpm and 610rpm for my smaller wheel. I settled at 450rpm to start and got really good results with the 12mm wide Stanley. The metal and the wheel were still cold to the touch.



                        Next up was the first victim. First thing I found was that unlike the Stanley, the sides weren't parallel enough to grip securely in the vise. I put the back of the chisel against the fixed jaw, one edge against the bottom of the vise and clamped the angled face with a dowel in the V of the moving jaw. I trued up each side so that I could grip the chisel and also so that the sides were square to the average of the face I was going to grind - otherwise it was going to tip front to back in that setup.
                        I found that initially the wheel was probably only making contact at one point around the revolution until it wore true. To be honest, this was quite helpful as it reduced the contact and hence the heat. With a much wider chisel once it was making full contact there was noticeably a lot more drag. I was still doing fine for heat until I was far enough down the chisel that the opposite side of the wheel engaged with the blade too. There wasn't any coolant at that end and the extra contact really made the heat build quickly at that point. I did end up blueing just the tip of the chisel but it should come out when I (hand) grind the primary bevel. Why did I grind the entire back when just an inch or two would have done? Well, to be honest, it just looked really bad. What I did have to do is once I got the deep gouges (from the factory grind) out of the middle was then to grind just the end as far as not making contact with the opposite side of the wheel. You can see a slight difference in colour (about 2/3 along) on this pic where that happens but it's not noticeable by eye. I knew it was cupped but I had to take off 0.5mm before it cleaned up! I did this in 0.04mm DoC steps. Probably took me a couple of hours (I'd have been there weeks by hand!) but this is the result:




                        As an idea of how it was before I started, this is another that has factory grind on the right hand side and quite a lot of hand lapping on a 140grit diamond plate on the left. You can still see the deep gouges of the factory grind. If you look closely, the top left corner is not planar with the rest so more would have to come off to get that to clean up.



                        I really struggle to understand how the factory grind can be that poor. Ok, that's not entirely true as it's obviously been outsourced at lowest cost....but it disheartens me that a once dependable brand could fall so far.
                        Just seven more to go *facepalm* Some of them aren't as bad though and the thinner ones should be less trouble.....I hope!

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                        • it's obviously been outsourced at lowest cost....but it disheartens me that a once dependable brand could fall so far.
                          Like the little bird: cheap, cheap, cheap.

                          Sad, Cheers
                          Roger

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                          • Originally posted by Cenedd View Post
                            ... grind just the end as far as not making contact with the opposite side of the wheel. ...
                            The trailing side of the cup is only a "problem" because your mill is well trammed. Just knock it out of tram & the the other side won't touch. 😉

                            Good work & it sounds like you're having fun, which is the most important part!

                            Comment


                            • Originally posted by Cenedd View Post
                              ...the first victim...Probably took me a couple of hours...
                              I am afraid that is way too much time to spend on such a cheap chisel. Though I understand it is what you have to work with.
                              12" x 35" Logan 2557V lathe
                              Index "Super 55" mill
                              18" Vectrax vertical bandsaw
                              7" x 10" Vectrax mitering bandsaw
                              24" State disc sander

                              Comment


                              • Originally posted by Bob Engelhardt View Post
                                The trailing side of the cup is only a "problem" because your mill is well trammed. Just knock it out of tram & the the other side won't touch. 😉
                                To be honest, it could also be that the handle end wasn't supported well enough since my vise isn't wide enough to grip the whole length. I did have a machinist jack under the handle but it could be that at that end it was part grinding and part deflecting the workpiece - which wouldn't be a problem if it didn't also tip the other end up into the wheel. Tiny amounts but when you're talking about 0.04mm advance, it's going to make a difference. I should point out that I realise that when I said 0.04mm DoC, that is the downfeed as marked on the fine feed wheel, not any sort of indicator and it will consist of an element of DoC and an element of wear on the wheel - how much, I don't know but there isn't noticeably less wheel than when I started

                                Originally posted by Bob Engelhardt View Post
                                Good work & it sounds like you're having fun, which is the most important part!
                                Thanks. I'd be having more fun if there weren't 7 more to do! Interesting learning curve though and undoubtedly a tool I'll be using again for other things.


                                Originally posted by ezduzit View Post
                                I am afraid that is way too much time to spend on such a cheap chisel. Though I understand it is what you have to work with.
                                I'm afraid you're right. I went for these because they were the very model my dad had - and he only bought the best. I suspected they weren't what they were in the 70's but I didn't realise how bad they were until I really got into it. It's always bugged me that most of his set had 'walked' over the years - and that's really what drove the selection. I'd have probably been better with something by Narex (there's plenty better still but I'm talking at the 'sensible' end of the price range) but they wouldn't have meant the same. Hopefully if I can get them all sorted out they'll be something I can take pleasure in.....currently they've somewhat soured the experience.

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