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Cutting a V-Grove Pulley

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  • Cutting a V-Grove Pulley

    I am trying something new. I need a smaller crank pulley for an vintage SCCA car I am trying to get going. I have a boxford CUD lathe so I figured I would try and make one out of aluminum. I saw a video on youtube where they used a parting tool at a 19 degree angle to cut the V groove. Is that the best tool to use? It worked in the video but seemed odd. I am thinking it may take a few attempts but I always learn from projects.
    You may only view thumbnails in this gallery. This gallery has 1 photos.

  • #2
    Anything that will cut the correct angle, and is not too dangerous to do is fine.

    IIRC, I used a tool that was actually ground to cut acme threads. The benefit of that was that it "shaved" the surface, so the surface was smooth. Parting tools tend to leave a "phonograph" surface, but would work and can leave a good surface with care..
    2730

    Keep eye on ball.
    Hashim Khan

    Everything not impossible is compulsory

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    • #3
      Have at it.

      V-Groove cut with a parting tool, after rouging.

      After the parting tool did the finish pass I had to add a sharp V at the very bottom with a form tool because that is how the part is on the drawing.

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      • #4
        Thank you for the replys! I ended up ordering a svvcn 3/8 holder to try. Its another Youtube recomendation by someone cutting a pulley. I will try it and see it the helps the process.

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        • #5
          Parting tool works great for cutting V grooves. Rough it out as seen in post #3. Do the finish pass using the compound set at that 19*. It means breaking into the setup to change sides, but it's easy enough to do. Don't think you will need a form tool for the bottom of the groove. A flat bottom the width of the parting tool should work, as long as that width is narrower than the flat on the inside of the

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          • #6
            Originally posted by tom_d View Post
            Parting tool works great for cutting V grooves. Rough it out as seen in post #3. Do the finish pass using the compound set at that 19*. It means breaking into the setup to change sides, but it's easy enough to do. Don't think you will need a form tool for the bottom of the groove. A flat bottom the width of the parting tool should work, as long as that width is narrower than the flat on the inside of the
            This was not a V-Sheave but a groove for a quick clamp liquid coupling, this would also not require a sharp V but that is how it is on the customer drawing (-:
            All angles done with a parting tool.
            Last edited by Bented; 07-01-2021, 06:24 PM.

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            • #7
              If you've got a lathe with enough ass you can just grind a double sided form too to finish it in after roughing (finishing one side at a time). If it was a production job on a manual lathe, I'd absolutely do it that way. But for a one-off, I'd just cut the angles with a compound and a radius grooving tool.
              21" Royersford Excelsior CamelBack Drillpress Restoration
              1943 Sidney 16x54 Lathe Restoration

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              • #8
                Originally posted by The Metal Butcher View Post
                If you've got a lathe with enough ass you can just grind a double sided form too to finish it in after roughing (finishing one side at a time). If it was a production job on a manual lathe, I'd absolutely do it that way. But for a one-off, I'd just cut the angles with a compound and a radius grooving tool.
                No compound on this machine.

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                • #9
                  I found that a form tool is best on Aluminium Pulleys, the photo shows one that I made earlier this week. It is 100mm diameter, 38 degree groove to suit an M section belt. I now have to machine the inside to accept a Taper Lock Bush.

                  Click image for larger version

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                  • #10
                    Originally posted by Bented View Post
                    After the parting tool did the finish pass I had to add a sharp V at the very bottom with a form tool because that is how the part is on the drawing.
                    Nice lookin' job when it's all done.

                    Rule number xxx; the customer is always right. Even if it makes things unnecessarily more expensive, or obviously compromises the structural integrity of the design.

                    When doing parts to a MIL. spec drawing we sometimes referred to these as a "TFP41" print. Don't dare question (potentially insult) the designers expertise,
                    it's an MIL. TFP41, so you simply "Make It Like The Friggin' Print For Once!"



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                    • #11
                      Originally posted by Bented View Post

                      No compound on this machine.
                      That was directed at OP. Obviously I would do it differently on a CNC lathe.
                      21" Royersford Excelsior CamelBack Drillpress Restoration
                      1943 Sidney 16x54 Lathe Restoration

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                      • #12
                        Thank you for the replies, I always learn new things when I post here.

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                        • #13
                          Technique may vary depending on the machine. Some high powered machines can get a really good finish, when the same tooling on a lower power machine that must run that tooling slower, gets a far worse surface.

                          It's good to remember the source, and the target, when evaluating advice.

                          2730

                          Keep eye on ball.
                          Hashim Khan

                          Everything not impossible is compulsory

                          Comment


                          • #14
                            Originally posted by J Tiers View Post
                            Technique may vary depending on the machine. Some high powered machines can get a really good finish, when the same tooling on a lower power machine that must run that tooling slower, gets a far worse surface.

                            It's good to remember the source, and the target, when evaluating advice.
                            Yes I have a pretty small and only 3/4hp Boxford CUD lathe. Its not cnc, not even a power cross feed, but I am learning how to make the most of it. I looked for a nicer lathe, but all I keep finding are absolutely worn out USA stuff or import stuff that you cant get parts for it somthing breaks. So the Boxford stays in the shop and I really think the lack of skill on my part is a bigger factor in making parts. Thank you for the advice. I will experiment and see if I cant knock out a v belt pulley. The materials are not a lot of $ so if I mess up its not the end of the world.

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                            • #15
                              You don't need a sharp V at the bottom of the V-groove. (Look at a V-belt)
                              12" x 35" Logan 2557V lathe
                              Index "Super 55" mill
                              18" Vectrax vertical bandsaw
                              7" x 10" Vectrax mitering bandsaw
                              24" State disc sander

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