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Can cutters be sharpened on a surface grinder?

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  • Can cutters be sharpened on a surface grinder?

    I opened a new thread a while back asking what features were good/ bad on small T&C or Surface grinders but it didn't attract many responses (although the few I got were interesting). My opportunities to use these machines have been limited so I was hoping to pick up a bit of group knowledge, enabling a more informed view on these machines.

    I have a whiff of a 10"x5" surface grinder at the moment, so to ask the question in another way, how easily can surface grinders be used/ adapted for sharpening cutting tools (lathe or mill). Is it just a matter of changing wheels/ guarding and mounting some jigging (a false table for example) or is the basic machine design such that it won't ever get the result that I'd expect?

    Michael

  • #2
    You would have to make a lot of jigs to be able to do this .

    adapt 5c collet jigs or ER ones

    and it may even ruin your wheels for surface grinding operations.

    7 inch wheels/ stones are not cheap ...you dont put a home depo or orable freight wheel on a surface grinder......the last one i bought from msc j&l cost in the region of £40.
    some operations would no doubt involve using the side of the wheel.

    Some arbour adapters and the spindle itself, are only made for holding surface grinder wheels...and there is a chance that there wouldn't be one for holding cup wheels or dedicated wheels.

    A 7 inch surface grinder wheel spins at something like 3000 rpm
    anything smaller has to spin even faster...i think most proper tool and cutter grinders which have wheels and cups under 4 inches in diameter spin at 6000 rpm

    Anyway ..just some thoughts ..others will contribute or shout me down .

    all the best.markj

    Comment


    • #3
      http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

      Made to be used on a surface grinder.

      Mark I didn't see any mention in the OP about 7" wheels, he may have 6" wheels and you can get away with all sorts of wheels if you are just licking the ends up, you want sharp, not 4 micro inches of finish.

      Lets face it you sharpen a lathe tool on a HF grinder without any worry, same applies.
      .

      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



      Comment


      • #4
        Michael,

        I'm sure you could, to an extent. You can use a lathe as a milling machine, you can use a milling machine as a lathe. In both cases, you're limited and lose flexibility. Same applies to swapping the roles of a surface grinder and a T&C grinder.

        When secondhand T&C grinders are on sale, thir value is usually halved if they don't have all the 'bits' (centres, fingers, workheads etc). As Mark says, you need lots of add-ons not found on surface grinders to do all that a T&C grinder will.

        But you can do some stuff, easily. Sharpening the ends of end mills, for instance - this thread on PM shows how: http://www.practicalmachinist.com/vb...rinder-200706/

        Not quite sure how easy it would be to resharpen all edges on a side & face mill, but simple stuff's possible. Equally, wood planer blades are easy enough with a jig to hold them.

        Lathe tools could probably be done with a 2 or 3 way swivel vise - it's just a set of 3 facets at the angles you fancy.

        T&C grinders usually allow you to swivel the table - this could be done on a surface grinder by offsetting the centres, or (if grinding from above) by making variable height centres.

        T&C grinding tends to be time consuming enough as it is - using a tool not designed for it in the first place isn't going to help. However, in the home shop, time isn't always the biggest motivator - you may be short of space, or cash, limiting you to one machine. You may just enjoy doing a job against all the odds - and come away feeling happy. Which, for those of us not making a living at it, is one of the main reasons to be messing with all this junk in the first place...

        Ian
        All of the gear, no idea...

        Comment


        • #5
          Michael, you could make an adjustable fixture to hold the lathe cutters and cut nearly any angle you may want. I have a fixture to grind HSS thread cutters on my surface grinder and it does an excellent job but it is not adjustable.

          I have a two wheel tool grinder sold by Horrible Freight that does a good job free hand or with the guide. To grind lathe tools it is much easier to use the tool grinder than to have to set up the cutter in a fixture and use the surface grinder.

          However, if you have lots of time and not in a hurry to get a job done the surface grinder will produce a much more accurate cutter than you can produce by hand.
          It's only ink and paper

          Comment


          • #6
            Surface Grinder

            Michael,
            I use my Harig surface grinder to sharpen end mills, lathe tooling and also horizontal mill tooling. For lathe tooling I purchased an inexpensive small suction base adjustable vice. These are used to hold small items and the vice itself can be adjusted to almost any angle. I removed the lever operated suction base and installed a flat steel base which holds the vice securely to the magnetic base of the surface grinder. The vice has also proven to be very useful for many other grinding projects. As I remember the original vice new cost like $15 US.

            Comment


            • #7
              Originally posted by John Stevenson
              http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

              Made to be used on a surface grinder.

              Mark I didn't see any mention in the OP about 7" wheels, he may have 6" wheels and you can get away with all sorts of wheels if you are just licking the ends up, you want sharp, not 4 micro inches of finish.

              Lets face it you sharpen a lathe tool on a HF grinder without any worry, same applies.
              What i meant is some cheapo wheel on his maybe nice surface grinder may vibrate like crazy despite best effort to balance it
              i suspect that the cheapo wheel would damage the bearings of his nice surface grinder

              if it isn't a nice surface grinder ..then he can do what he wants.

              all the best.markj

              Comment


              • #8
                I recently got a Delta Toolmaker grinder, looks like the one shown here:
                http://finance.groups.yahoo.com/grou...guid=205784240

                Some time ago I built a Brooks-Stent to sharpen tools and it works well:
                http://www.gadgetbuilder.com/Brooks%20Grinder.html

                Every time I walk by the Toolmaker I think about trying the work head and jigs from the Brooks on it. I need a wheel adapter to hold a cup wheel so haven't done it, yet.

                The Toolmaker has a nice spindle and the table controls seem fine for use with the jigs I have. In its basic setup it looks a lot like the Brooks, just bigger. The only obvious drawback is the motor isn't reversible so there might be more of a wire edge on cutters or I'd have to figure out how to work on the other side of the wheel.

                There are a couple areas I ran into that make end mill sharpening more challenging than originally expected. Gashing isn't often mentioned but it crops up as soon as you sharpen a cutter with a large chip. Sharpening end mills for center cutting is a challenge with my setup - doze off for a second and it won't be center cutting ;-) See:
                http://www.gadgetbuilder.com/Brooks%...ill_Sharpening

                Now that I can sharpen end mills I use them more aggressively, higher RPM and more feed, and oddly they seem to last longer. Apparently trying to baby them to improve longevity was counter productive.

                Bottom line: with a little work making jigs, I think a surface grinder should sharpen cutters nicely.

                Comment


                • #9
                  I have a Darex air bearing that is intended for use on a surface grinder. With it you can sharpen the flutes on end mills with a cup wheel. Think I paid something like $150 on cragslist.

                  Vid I took for an earlier discussion on air bearings:

                  Comment


                  • #10
                    its a different answer depending on whether you want to do a right hand (or was tha left?) hss lathe tool or a 6" long slab cutter for the horizontal mill. For average stuff, lathe bits, twist drills and end mills its entirely doable...but you'll be making some stuff

                    Think through what each machine does already and what it would need to do to accomplish a specific task - anything not there are already, means you're building a fixture; could be univise, tooth rest, table, air bearing, whatever.

                    There are some common features between the machines, but keep in mind most guys when shopping for a T&CG will be highly attuned to how much tooling it comes with - its rather useless itself without the tooling....and the surface grinder will come with zero tooling for tool and cutter grinding.

                    For regular lathe tools, there is little point except for threading (the rest just do on the bench grinder). I the last month I've done 60 degree, 55 and acme - especially nice on the acme as the larger helix means you've got to pay attention attention to the clearance angle. Having a univise to get this done perfectly is a nice treat....compared to the bench grinder and a template. I came up with a design for univise, documented somewhere herein, that does all this plus does a bang up job on drills. If you build that, and bought or built an airbearing, you could do a first class job on lathe bits, drills and end mills which for most guys is 99% of it.
                    .

                    Comment


                    • #11
                      That device in post # 3

                      http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

                      Here's one in the flesh.



                      Tipped up at the secondary relief angle and would be held on a magnetic table.




                      Now tipped at the primary angle for doing the cutting edge, again on the sticky table.

                      Had a quick sort out in the scrap HSS box and found this 12mm cutter which has seen better days.



                      So a quick wazz up on the surface grinder which at first glance looks to have 5" of wheel left from it's original 7" and we finish up with this about 5 minutes later.




                      Not the best cutter in the box but given I have not used this thing for well over a year I thought it was passable ?

                      It's certainly sharp as proved by 3 pints of O RH + claret all over the workbench. [ Can you catch AIDS off a 12mm cutter ? ]

                      They do make a decent job if you spend a bit of time and practice, best to get a big box full and it soon works out OK.

                      No excuses but my main problem tonight was the grinder is in a dark part of the shop and it lacks it's own light, with a decent light I could have done it a lot quicker and better.
                      .

                      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                      Comment


                      • #12
                        Thanks Guys.
                        To fill in some blanks, the machine under consideration has 6" wheels and I'm looking at doing things this way because of lack of space (I want something that I can mount on a bench top and is around 2' x 2') primarily but funding does come into it. Even this machine is bigger than space available but close enough to consider. It would probably be one of those "use for 1/2 an hour once every couple of months" machines - a second reason not to invest too much into it.
                        My first choice would be for a proper T&C grinder but most of the ones that come up for sale around here are big industrial beasts. Independent of size, usually they don't have all the fittings with them, so making things up would be required anyway. The thought was that a surface grinder may be able to duplicate the more common T&C tasks.
                        I currently sharpen lathe tools on a bench grinder and while for GP use it produces acceptable results, as Mcgyver mentioned for thread work something more precise is better. End mills I don't sharpen at all once I've dinged them so that's something that would be nice to do (the pile is growing), and then there are the second hand cutters I pick up at S/H stalls.
                        Armed with a device like the one John has pictured and a tilted fixture for lathe tools, probably 90% of my T&C grinding needs could be accomplished relatively easily. The rest would need more fixturing or sending out.

                        Michael

                        Comment


                        • #13
                          Originally posted by form_change
                          .
                          Armed with a device like the one John has pictured
                          just remember that does the end, the wear is on the cutting edges on the side, the OD.....you either have to grind A LOT off the end, or get an air bearing to do the OD helix to sharpen them. Its really worth having, one does better work imo when there is always the right sharp cutter available
                          .

                          Comment


                          • #14
                            Originally posted by Mcgyver
                            just remember that does the end, the wear is on the cutting edges on the side, the OD.....you either have to grind A LOT off the end, or get an air bearing to do the OD helix to sharpen them. Its really worth having, one does better work imo when there is always the right sharp cutter available
                            Very valid point, to be honest I only bother doing end mills 14mm and above due to cost reasons, the smaller ones are just not worth doing on a cost basic for me, may be different with others.

                            If I get a damaged one I chop the end off with a slitting saw, then regrind.

                            If I get one with worn or damaged flutes then it gets binned, cost wise for me it's not worth the effort of doing flutes and then finish up with an undersized cutter, again other may find this different.

                            The other attachment that's very useful is this one.



                            I have seen these in two sizes and this is the larger one, these were bought for a special job, nothing to do with tool grinding and I get an extra one shipped in to see how useful it is.

                            To be honest it's a tad too big for my grinder but it does spin in 4 planes and is very universal. Wish I had got the smaller model but they were too small for the job in question and the paperwork would have looked bad with 7 of one size and one of the other
                            .

                            Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



                            Comment


                            • #15
                              Can end mills be sharpened on a surface grinder? Of course they can! They can also probably be sharpened on a washing machine motor and a piece of concrete. Should they? No, in both cases. Put a value on your time!! At one dollar per hour it's a dead loser.

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