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  • #31
    I have one of the t-shaped profile blades with a sort of v-grooved top. Get one of those and you will have next to no grinding to do. The top v-groove (chipbreaker?) is already part of the blade. The side clearances are done for you by virtue of its t-shape. You only have to grind the front to sharpen it and that's a no-brainer. You walk it up to your bench grinder wheel like the wheel were a piece being parted with the top of the blade right on center of the grinding wheel (eyeball) and grind until the wheel touches from top to bottom. The curvature of the wheel will provide some relief at the front. Move it side to side while doing this to prevent grooving the wheel.

    Really slick way to do things if you ask me.

    Paul
    Paul Carpenter
    Mapleton, IL

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    • #32
      Cut-Off Blades

      Amen to the comments about using cheap cutoff tools. I fought Chinese HSS for some time, all with poor results. I recently bought a 3/4" wide blade for carbide inserts. It fits a holder that I was using with HSS.

      It wades through everything and puts a grin on my face every time I use it. The blade is a AGIH-19-2 Accupro unit with MGTN-2 inserts. This small blade will only handle up to 0.093 insert thickness, but easily cuts up to 1" material. When the pocketbook permits, I'll get a larger blade and inserts to will let me make wider cuts and handle thicker material.

      Yeah, good carbide tools are expensive, but they last forever, or at least longer than I will.

      Comment


      • #33
        Part off Blades

        Of course, there are designs to use- worn out hacksaw blades.
        One of the best builders of yesteryear used them almost exclusively.

        If one is loathe to such flights of fancy, you can always use a Quorn T&C which will sharpen them- not the first and last tooth but you can't have everything. Prof.Chaddock did it and I doubt that there are many here who can keep up with him.

        Now this 'ere 9x20, it will take a subtable. Oi' did it and I transfered all my Myford goodies onto it. It isn't rocket science drilling and tapping a few holes here and there to suit doesn't require a genius.

        Geniuses post on Photo-phuket, me-too old or thick- sorry.
        I keep looking East for miracles but my old eyes
        just water!

        N

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        • #34
          Originally posted by pcarpenter
          I have one of the t-shaped profile blades with a sort of v-grooved top. Get one of those and you will have next to no grinding to do. The top v-groove (chipbreaker?) is already part of the blade. The side clearances are done for you by virtue of its t-shape. You only have to grind the front to sharpen it and that's a no-brainer. You walk it up to your bench grinder wheel like the wheel were a piece being parted with the top of the blade right on center of the grinding wheel (eyeball) and grind until the wheel touches from top to bottom. The curvature of the wheel will provide some relief at the front. Move it side to side while doing this to prevent grooving the wheel.

          Really slick way to do things if you ask me.

          Paul
          I also use the t-shaped blades and they work well for me. I DID have to mill out the top of the toolholder so the blades would sit flat though. As for grinding I do it as Paul said but instead of using the bench grinder I made an arbor for the stone that mounts in my chuck and set the hight of the blade with the toolholder. Here is a pic. ( wrong stone but was the one mounted on the arbor at the time for picture )

          Ernie (VE7ERN)

          May the wind be always at your back

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          • #35
            Part off Blades

            With a change of computer, I had wiped this site from my Favorites.

            OK, now have a look at www.haythornthwaite.com and go into this modellers workshop projects.

            Suffice to say that the Thomas rear parting tool is depicted. I made one exactly like this- and a few more identical items.

            Norman

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            • #36
              Norman, thank you for the link, very impressive stuff there.

              Comment


              • #37
                Yes, thank you for the link, Norman.
                I have visited a great number of model engineering websites, but that one was new to me.


                One question regarding the rear parting tool described here :
                Can this be used on a short-cross-slide Myford (ML7)?
                When comparing the pictures with my lathe, it looks like it fits ok, but might be a bit cramped.


                .
                Thomas

                Problems worthy of attack prove their worth by hitting back
                - Piet Hein

                Comment


                • #38
                  Originally posted by Norman Atkinson
                  Perhaps the experience of thousands of other Boxford and Myford owners is wrong or mis-guided.
                  Despite it all, castings for the George Thomas rear parting tool seems undiminished. Moreover, the design has now moved onto a larger one suitable for applications on larger lathes than the Boxfords, Myfords and cheap sh1te Chinese 9x20's etc.

                  Again and again, people with far vaster experience than I have have been using castings etc from HemingwayKits. I, on a succession of lathes including a 9x20 over decades have had no problems.

                  It does suggest that that I have been using a failed or very inferior system all these years.

                  Where have I and the rest of us, gone wrong? Well????

                  Regards

                  Norman
                  Glad that method treats you well. Another method that doesn't require running the tool post backwards, casting kits, or sharpening of hss is to use an Iscar or similar carbide insert parting tool.

                  Comment


                  • #39
                    Part off Blades

                    Greetings Thomas( and all)

                    As it comes from HemingwayKits or just using what you have in the scrap box and 'the book', it will fit onto the back of a short boring table on the ML7.
                    Thomas( GHT- Thomas) designed it to part off at 2" diameter maximum.

                    What doesn't show up in the otherwise excellent photographs is that the 'turret' top can be rotated 90 degrees so that more space can be gained when not parting off.

                    May I ramble on? There are two blades and by rotating them, they lock in position with a spring loaded peg and you can use which ever thickness is suitable for the job in hand.
                    However, GHT was a vey clever and thoughtful engineer and you CAN change the turret or remove it but you can also fit a new turret which could take a spare lathe tool which could, say, be for chamfering work.

                    When I got my casting etc( a long, long time ago) it had a plan for a parting tool on on side and a chamfering tool on the other.

                    Thomas- my E-mail address is [email protected] and I have just scrapped a 'long' ML7 and the top etc is still there.
                    Oddly, I'm in Newcastle for the record.

                    Hope the rest of you find this is interesting!

                    Cheers

                    N

                    Comment


                    • #40
                      Part off Blades

                      Parting off? Well, not really!

                      I thought that if I was still a bit - crook as they say in OZ, it would make sense to pass along a few more hints from 'goggling' -sorry 'Googling'

                      Have a go at 'GadgetBuilder.com'. Understandably, there is a lot of stuff which appears elsewhere. Nevertheless, it is better to a bit of duplication than nothing at all.

                      Whilst you are in Googling mood, there is an old site- out of date and perhaps, you will not be able to get all of it. However, try 'Chris Heapy'
                      A Japanese modeller sort of resurrected it and newcomers will really enjoy the wealth of information.

                      Tell me, tell us of whether you have found both sites useful.

                      Meantime, more eyedrops and a rest up.

                      Cheers
                      Norman

                      Comment


                      • #41
                        Years ago they used to have a man with a red flag walking in front of cars to warn people of the vehicle approaching and avoid accidents.
                        It worked very well, but then they had to go and make progress using more modern technology and found a better way to do things Dammit $*!!

                        Of course, some still maintain that this was the only way to do it, and the idea should not have been forgotten, others just shrug and use the new stuff which is easier, quicker, and doesn't need the additional burden of a man in front.

                        Bit like parting tools really. Rear parting toolposts still work well, but a modern approach like this : http://www.greenwood-tools.co.uk/shopscr23.html works even better, even on speed and rigidity-challenged small lathes like the Myford.
                        I've used mine on the Myford and Colchester on everything thing from small stainless and sliver steel bars to a 2" lump on EN19T, and I would never go back .

                        Peter

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                        • #42
                          Part off Blades

                          Peter,
                          Sadly these new fangled gadgets come at HALF the price of a 2nd Hand professional tool and cutter grinder. I bought a Clarkson for £100.
                          Again, I was offered an unusual Stent which was fabricated for the same- with a heap of accessories.

                          I was in HongKong and have connections there. Red Flags still cost money there.

                          The Chinese 'Luck Money' is due by the 12th- want a coin?

                          Sorry, but I am living and succeding in this weird economic climate.
                          When I went to college- one grossed up £50 as it was paid out of net and therefore taxed income( at 40%) Hasn't changed much- it was 50% then

                          Regards

                          Norman

                          Comment


                          • #43
                            dockrat,

                            Thanks for the photo, that is the blade I have been using but had not ground the radius as you have so I'll give this a try. Also just set up my new QCTP, 100 series, so I will utilize the parting tool holder that came with the set. Does the angle that your tool holder presents the blade to the work impact + or - using that QCTP configuration? I see that rear tool post as interesting and a nice project with practical use but it will not fit to my Atlas so will save it for a future lathe.
                            regards

                            3t

                            Comment


                            • #44
                              Ah but but we weren't talking about Tool & Cutter grinders Norm, I think the discussion was more along the lines of parting off blades

                              Of course these days £50 is nothing really, about what I spend on a Chinese takeaway for the family, and with the same carbide insert having been in there for about a year or more now, even more of a bargain.
                              You don't have to be sad and sorry all in one post Norm, and despite the cost of flags in China you can't accuse them of being guilty of neo-Luddism

                              Peter

                              Comment


                              • #45
                                Part off Blades

                                The subject WAS a 5/8th Parting tool blade held by somebody who found it necessary to fling the whole lot into the (Roman) Forum to be torn to bits
                                ( Well metaphors and whatsits permitted) The blade was HSS and not carbide and unusually for me, I kept to the question( at the beginning, anyway)
                                <Wait for roar from the Plebians>

                                Now Peter, I could have been naughty and got unfrocked or worse for suggesting that he could have made a tool and cutter grinder from plastic( err uhm). Instead, I gave a thoroughly good economics argument of what in the year of our Lord 2009 what the economic choices were- TWO parting off tools ( Minus holder) and an all singing whatsit which would sharpen every tool in the armoury until the end of time. It was more or less conditional that the guy would accept HSS ( which he had).

                                OK - Peter, you remind me of Huskisson- no, that was a train but that, if my economic history class continued next week would go to Brighton- and Red Flags abandonned.( that's the history- fellas- of Reckless Speed)

                                So £50 eh? for all those poor, starving children! Peter, my friend, I could have got 19(yes) courses at the start of the Year of the Ox for £16 a head- of which £1 went to buy Teddies for Kids in Hospital.



                                Right off topic-- Kung Hei Fat Choy! But it does wish you all a happy(chinese) new year.

                                Ling_Sam Sam Yee_Say-Say

                                Norm

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