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  • internal snap ring groove?

    Can anyone tell me how this is done? Is there a special tool for it, can anyone describe the geometry? It seems to me that it needs to be ground similar to a boring bar, but thin and parting tool like for the cutting edge. It seems that grinding this from a HSS blank will leave very little shank for supporting the cutting edge. It doesn't need to cut that deep, but what I have pictured in my head does not look like it will stand up to turning forces...

    I have thought about soldering a piece of parting blade to the end of a bar, but I think there wont be enough relief on a parting blade to keep from rubbing the work. Can anyone clear this up for me?

    Thanks,
    Jason

  • #2
    How 'bout a grooving tool ? Basically like a solid carbide boring bar except the cutting edge is ground like a miniature sideways parting tool. They are solid carbide $$$, and even so, you'll still need to feed it gently to avoid excessive tool flex.

    Get them from KBC, or McMaster-Carr. I don't think Enco carries them yet. The brands I use are Circle and Micro100.

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    • #3
      Looks like Enco does carry just a few grooving tools.


      http://www.use-enco.com/CGI/INSRIT?P...MPXNO=19499565

      Solid carbide tools are not cheap, but you need the rigidity. You could grind your own out of HSS if you are motivated, and if you don't need carbide's rigidity for your application.

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      • #4
        It seems that grinding this from a HSS blank will leave very little shank for supporting the cutting edge.


        That's it exactly.



        It doesn't need to cut that deep, but what I have pictured in my head does not look like it will stand up to turning forces...


        If it's ground right it will. Most snap ring grooves aren't that far from their opening(at least if it's engineered right)


        An easy way to make a cutting tool is to chuck up a piece of drill rod a little smaller that your opening and cutting a disk at the end . The disk being as wide as your snap ring groove. temper it and start grinding away the parts you don't want.

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        • #5
          I have several that I have ground from 1/4" to 1/2" sq. HSS tool steel and I use the same cutter for external and internal. To use it for internal you have to grind clearance for the diameter of the bore. The shape of the cutter is like a keystone looking down on the top surface.

          I have them from .020" wide to 3/16" I use them in a boring bar for internal snap ring grooves. I also cut O ring grooves with them. If I don't have one the exact width I need I use a narrow one and plunge cut and move the cutter and plunge again until the groove is wide enough.
          It's only ink and paper

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          • #6
            Originally posted by jacampb2
            ..................
            I have thought about soldering a piece of parting blade to the end of a bar, but I think there wont be enough relief on a parting blade to keep from rubbing the work. Can anyone clear this up for me?

            Thanks,
            Jason
            Seems to me if you milled a slot on the end of some roundstock and then silver soldered a piece of parting blade in place it would hold till hell wouldn't have it. I got some parting blades that small from ebay sometime back as part of a parting kit for very small projects. It was maybe $15.00. Something like this:

            http://cgi.ebay.com/SMALL-LATHE-PART...item5d26e3d398
            Last edited by Your Old Dog; 11-12-2009, 09:37 PM.
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            • #7
              Grooving

              The geometry and shape as per MTNGUN's post are correct.



              If if were me - and given that the groove will probably not be too/very deep - I'd just use a bit of mild steel bar/rod (cold rolled for preference, but hot-rolled at a pinch) as a boring-bar and either silver-solder a bit of 3/16" square HSS tool-bit to the end of it and grind to shape/suit or use a bit of REAL HSS power hack-saw blade and cut a bit of that out and silver-solder it onto the end of the boring bar and grind it to shape.

              The boring-bar will be plenty stiff enough if you keep it short and take it slowly. The silver-soldered tool-bit will work pretty well under those conditions as well.

              Slow-w-w-w speed and plenty of cutting oil (drilling and tapping oil or hydraulic (gear-box etc.) oil will work well too) and take it slow and easy and you will be OK.

              There should be no need to, but you can mill a shoulder/shelf on the end of the boring-bar if you like to "assist" the tool.

              Its NOT a "tear-ar$ing" or "production" job here - just a "take it easy" HSM-er job.

              Don't worry about the silver-solder buggering up the HSS tool-bit as while it may well "draw" some of it "raw state" qualities - it will be more than good enough for this job.

              Keep the boring-bar as big and as short as you can to avoid "chatter" as that more than anything else will adversely affect the cutter and the job. Keep your cross-slide gibs "firm" and clamp you top-slide and don't have the tool-post front/left face forward of the front/left side of the cross-slide.

              I've "stick" and MIG-welded HSS tool-bits too and they've done pretty well all-in-all.

              Just "dunk" it in water or oil as soon as its welded and it will be OK.

              Keep the tool edge/stoned to be razor sharp.

              My guess is that you have already got - or can get- all that is needed in your shop.

              "Chatter" will "kill" TC but HSS takes it pretty well in its stride - as it always has - provided that it is a good quality HSS tool-bit.

              If the tool does "chatter" just grip the boring bar between a couple of fingers on your right hand or just rest a couple of fingers on it.

              For what its worth, when I am drilling or tapping or doing form-work on the lathe I spit (saliva) on my finger and use that as a cutting oil - works really well - but watch out for cuttings on you fingers!!. Pissing in a tin and putting that on a cut (with a brush - or pour it - don't lick it!!) works well too. It was a good practice years ago. Urine works pretty well,as a heat-treatment medium too - but keep up-wind of it!!

              Don't even THINK of let alone try crapping on it - as its bloody awkward squatting on the lathe bed, stinks like hell and doesn't work either - but it sure does clear the shop!! Yep - I've seen it!! But I won't confess to having done it!!

              By definition, grooving is similar to rutting.

              Groove the job - but don't rut it!!

              Edit:
              corrected image link.

              Sorry YOD as I "crossed wires" with you as I took a break for a while in my typing and didn't see yours until I came back, finished typing and posted.
              Last edited by oldtiffie; 11-13-2009, 12:59 AM.

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              • #8
                Machining snap ring and o-ring grooves

                Go to Thinbit.com they make some good quality grooving and threading tools.

                The make or buy decision is not allways an easy one. If you decide to buy a grooving tool theirs are very nice.
                Byron Boucher
                Burnet, TX

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                • #9
                  Thanks guys, I think I am going to take a stab at making it. As of yet, this is the first time I have ever considered using a snap ring, and it is a one off deal, I can't see buying tooling for it if I can do it myself-- if I start running into the need for it again and again, then I will look into these more long term production suggestions.

                  Thanks,
                  Jason

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                  • #10
                    Iv done ID work using a boring bar that holds a small square HSS bit (3/16" or so), you just grind the small bit as needed.. it works best if your bore is big, if its under 1/2" or even 3/4" a complete custom grind might be best.
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      Just grind one up from a chunk of HSS. It isn't hard and it works fine. I have been using this inside thread cutter I made for years.

                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        Originally posted by Black_Moons
                        Iv done ID work using a boring bar that holds a small square HSS bit (3/16" or so), you just grind the small bit as needed.. it works best if your bore is big, if its under 1/2" or even 3/4" a complete custom grind might be best.
                        I like this idea a lot, and IIRC I have seen it used before. The bore is 42mm, so it is plenty large enough, and I have scraps of HSS around. I don't really want to screw it up, this is the cartridge for my high speed spindle, and I already have about 8 hours in the project, I'm hoping not to scrap it of a screwed up snap ring groove.

                        From what I can find online, the average snap ring groove is .062" wide, that seems like an awful thin grind for the cutting edge of the tool-- I think I am going to try to groove a piece of scrap before I tackle my nearly finished cartridge...

                        Thanks again!
                        Jason

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                        • #13
                          Groove geometry can be critical. A quick Google found this:

                          http://catalog.daemar.com/viewitems/...uresortid=262#

                          Phil

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                          • #14
                            Simplest way I have found is to make a cutter using a length of 1/2" dia bar. Drill and tap into one end on centre line cross drill(just over 1/8") to take a 1/8" dia hss round rod shape end of 1/8 rod to cut required shape fis with allen headed bolt - bingo. Smallest that I think you could make would be about 3/8 dia bar smaller than taht gring toolbit as others have said.

                            peter
                            I have tools I don't know how to use!!

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                            • #15
                              Cir-clips

                              Originally posted by jacampb2
                              I like this idea a lot, and IIRC I have seen it used before. The bore is 42mm, so it is plenty large enough, and I have scraps of HSS around. I don't really want to screw it up, this is the cartridge for my high speed spindle, and I already have about 8 hours in the project, I'm hoping not to scrap it of a screwed up snap ring groove.

                              From what I can find online, the average snap ring groove is .062" wide, that seems like an awful thin grind for the cutting edge of the tool-- I think I am going to try to groove a piece of scrap before I tackle my nearly finished cartridge...

                              Thanks again!
                              Jason
                              Jason.

                              Don't think it is too big a problem or a problem at all. Check out what is needed and what is available.

                              Here is a start:
                              http://www.anderton.co.uk/products.asp?s=2#basic

                              http://www.google.com.au/search?hl=e...q=7&oq=circlip

                              http://www.google.com.au/search?hl=e...aq=9&oq=circli

                              There will be others.

                              To alleviate your concerns about the tool, use the widest cir-clip with a need for the shallowest groove that will suit your purpose.

                              Don't forget to consider the force - and the plier/s - necessary to close the cir-clip so that you can get the cir-clip in and out. The force needed on a cir-clip that size can be considerable. You may be limited by the cir-clips available - or their cost.

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